ISO/DIS 10328:2025(en)

ISO/TC 168/WG 3

Secretariat: DIN

Date: 2025-04-22

Prosthetics — Structural testing of lower-limb prostheses — Requirements and test methods

© ISO 2025

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Contents

Foreword ix

Introduction xi

1 Scope 1

2 Normative references 2

3 Terms and definitions 2

4 Symbols 2

5 Strength and related performance requirements and conditions of use 4

6 Coordinate systems and test configurations 5

6.1 General 5

6.2 Axes of coordinate systems 5

6.3 Reference planes 6

6.3.1 General 6

6.3.2 Top reference plane, T 6

6.3.3 Knee reference plane, K 6

6.3.4 Ankle reference plane, A 6

6.3.5 Bottom reference plane, B 6

6.4 Reference points 8

6.5 Test force 8

6.6 Load line 8

6.7 Longitudinal axis of the foot and effective joint centres and centrelines 8

6.7.1 General 8

6.7.2 Longitudinal axis of the foot 9

6.7.3 Effective ankle-joint centre 9

6.7.4 Effective ankle-joint centreline 10

6.7.5 Effective knee-joint centreline 10

6.7.6 Effective knee-joint centre 11

6.8 Reference distances 11

6.8.1 Offsets 11

6.8.2 Combined offsets 11

6.8.3 Effective lever arms L_A and L_K 12

6.8.4 Distance L_BT 12

7 Test loading conditions and test loading levels 12

7.1 Test loading conditions 12

7.1.1 General 12

7.1.2 Test loading conditions of principal structural tests 12

7.1.3 Test loading conditions of separate structural tests 12

7.2 Test loading levels and Test Ranges (R) 13

8 Values of test loads, dimensions and cycles 14

9 Compliance 21

9.1 General 21

9.2 Selection of tests required to claim compliance with this document 22

9.3 Arrangements for tests on samples of prosthetic structures including ankle-foot devices or foot units, required to claim compliance with this document 22

9.3.1 General 22

9.3.2 Particular arrangements concerning the ankle-foot device or foot unit 22

9.3.3 Particular arrangements and requirements concerning the part required to connect the ankle-foot device or foot unit to the remainder of the prosthetic structure 22

9.4 Number of tests and test samples required to claim compliance with this document 22

9.5 Multiple use of test samples 23

9.5.1 General 23

9.5.2 Restriction 23

9.6 Testing at particular test loading levels not specified in this document 23

10 Test samples 25

10.1 Selection of test samples 25

10.1.1 General 25

10.1.2 Selection of ankle-foot devices and foot units of appropriate size of foot 26

10.2 Types of test samples 26

10.2.1 Complete structure 26

10.2.2 Partial structure 29

10.2.3 Any other structure 29

10.3 Preparation of test samples 29

10.4 Identification of test samples 30

10.5 Alignment of test samples 31

10.5.1 Test samples for principal tests and optional separate tests on knee locks 31

10.5.2 Test samples for separate tests on ankle-foot devices and foot units 31

10.5.3 Test samples for separate static ultimate strength tests in maximum knee flexion for knee joints and associated parts 32

10.6 Worst-case alignment position of test samples 32

11 Responsibility for test preparation 33

12 Test submission document 34

12.1 General requirements 34

12.2 Information required for test samples 35

12.2.1 All test samples 35

12.2.2 Test samples for tests on ankle-foot devices and foot units 35

12.2.3 Test samples for static ultimate strength tests in maximum knee flexion for knee joints and associated parts 35

12.3 Information required for tests 35

12.3.1 General 35

12.3.2 For all tests 35

12.3.3 For static tests in torsion and on ankle-foot devices and foot units 36

12.3.4 For static ultimate strength tests 36

12.3.5 For cyclic tests 36

12.3.6 For tests in torsion 36

12.3.7 For tests on ankle-foot devices and foot units 36

13 Equipment 36

13.1 General 36

13.2 Equipment for the principal tests specified in 16.2 and 16.3 37

13.2.1 End attachments 37

13.2.2 Jig (optional) 39

13.2.3 Test equipment 39

13.3 Equipment for the separate static test in torsion specified in 17.1 41

13.3.1 Test equipment 41

13.4 Equipment for the separate tests on ankle-foot devices and foot units specified in 17.2 41

13.4.1 Test equipment 41

13.5 Equipment for the separate static ultimate strength test in maximum knee flexion for knee joints and associated parts specified in 17.3 45

13.5.1 Extension pieces 45

13.5.2 Test equipment to perform static compression loading – (Compression testing machine or other equipment) 45

13.6 Equipment for the optional separate tests on knee locks specified in 17.4 45

13.6.1 End attachments 45

14 Accuracy 45

14.1 General 45

14.2 Accuracy of equipment 45

14.3 Accuracy of procedure 45

15 Test principles 47

15.1 General 47

15.2 Static test procedure 47

15.3 Cyclic test procedure 50

16 Test procedures – Principal structural tests 50

16.1 Test loading requirements 50

16.1.1 Preparation for test loading 50

16.1.2 Application of test loading 50

16.2 Principal static test procedure 52

16.2.1 Principal static proof test 52

16.2.2 Principal static ultimate strength test 56

16.3 Principal cyclic test procedure 60

16.3.1 General requirements 60

16.3.2 Test method 60

16.3.3 Performance requirements 64

16.3.4 Compliance conditions 65

17 Test procedures — Separate structural tests 68

17.1 Separate static test in torsion 68

17.1.1 General 68

17.1.2 Purpose of test 68

17.1.3 Test method 68

17.1.4 Performance requirements 70

17.1.5 Compliance conditions 70

17.2 Separate tests on ankle-foot devices and foot units 71

17.2.1 General 71

17.2.2 Purpose of tests 72

17.2.3 Separate static proof test for ankle-foot devices and foot units 72

17.2.4 Separate static ultimate strength test for ankle-foot devices and foot units 74

17.2.5 Separate cyclic test for ankle-foot devices and foot units 78

17.3 Separate static ultimate strength test in maximum knee flexion for knee joints and associated parts 84

17.3.1 General 84

17.3.2 Purpose of test 84

17.3.3 Applicability of the test to specific test samples 84

17.3.4 Test method 85

17.3.5 Performance requirement 86

17.3.6 Compliance conditions 86

17.4 Separate optional tests on knee locks 87

17.4.1 General 87

17.4.2 Purpose of tests 87

18 Test laboratory/facility log 87

18.1 General requirements 87

18.2 Specific requirements 87

19 Test report 88

19.1 General requirements 88

19.2 Specific requirements 88

19.3 Options 88

20 Classification and designation 89

20.1 General 89

20.2 Examples of classification and designation 89

21 Compliance with this document 89

21.1 General 89

21.2 Example of identifier layout 90

21.3 Identifier placement 90

Annex A (informative) Description of internal loads and their effects 91

A.1 General 91

A.2 Moment reference lines 91

A.2.1 General 91

A.2.2 Ankle moment reference lines 91

A.2.3 Knee moment reference lines 91

A.3 Internal loads 91

A.3.1 General 91

A.3.2 Axial force F_u (axial compression) 92

A.3.3 Moments 92

Table A.1 — Positive internal forces and moments with descriptions of their effects 92

Figure A.1 — Test loading condition I [see 7.1.2 a)] 93

Figure A.2 — Test loading condition II [see 7.1.2 b)] 94

Annex B (informative) Reference data for the specification of test loading conditions and test loading levels and Test Ranges (R) of principal cyclic tests 95

B.1 Background statement 95

B.2 Specification of different test loading conditions and test loading levels for principal cyclic tests 95

Table B.1 — Values of ankle and knee moments related to test force F = F_cr for different test loading conditions and test loading levels of principal cyclic tests for Test Range 2 and 3 (R2, R3) 96

Table B.2 — Calculated values of axial force and twisting moment related to test force F = F_cr for different test loading conditions and test loading levels of principal cyclic tests for Test Range 2 and 3 (R2, R3) 96

Table B.3 — Values of ankle and knee moments related to test force F = F_cmax for different test loading conditions and test loading levels of principal cyclic tests for Test Range 2 and 3 (R2, R3) 97

Table B.4 — Calculated values of axial force and twisting moment related to test force F = F_cmax for different test loading conditions and test loading levels of principal cyclic tests for Test Range 2 and 3 (R2, R3) 97

B.3 Calculation of axial force and twisting moment 97

B.4 Calculation of ankle and knee offset (see 6.8.1) 98

Annex C (informative) Guidance on the application of an alternative static ultimate strength test 99

C.1 Background statement 99

Annex D (informative) Summary of the records to be entered in the test laboratory/facility log 100

D.1 Log records required for the test equipment 100

D.1.1 Specific records of types of test equipment 100

D.1.2 Specific records of proof test of end attachments 100

D.1.3 Specific records of accuracy 100

D.2 Log records required for all test samples 100

D.3 Log records required for all tests 101

D.4 Log records required for principal structural tests 101

D.4.1 Specific records of principal static proof tests 101

D.4.2 Specific records of principal static ultimate strength tests 102

D.4.3 Specific records of principal cyclic tests 103

D.5 Log records required for separate structural tests 105

D.5.1 Records required for separate static tests in torsion 105

D.5.2 Records required for separate tests on ankle-foot devices and foot units 106

D.5.3 Records required for separate static ultimate strength tests in maximum knee flexion for knee joints and associated parts 110

Annex E (informative) Background information on the loading profiles generated by test equipment according to 13.4.1.2 for separate cyclic tests for ankle-foot devices and foot units according to 17.2.5.1 111

E.1 General 111

E.2 Loading profiles 111

E.2.1 Loading profile according to Figures 10 a) and 10 b) 111

E.2.2 Loading profile according to Figure 10 c) 111

E.2.3 Loading profile according to Figure 10 d) 112

Annex F (informative) Background Data (reduced) of the six-minute walk test for Adults (see[5]) 113

Table F.1 — Background Data, supporting the Numbers stated in 7.2.4 113

Annex G (informative) Guidance on the application of an additional test loading level P2 114

G.1 Background statement 114

G.2 Test forces of the proof test of end attachments 114

G.3 Test loading conditions for principal structural tests 114

G.4 Test loading conditions for separate tests on ankle-foot devices and foot units 114

Table G.1 — Test forces of the proof test of end attachments for test loading levels (see 13.2.1.2) 114

Table G.2 — Test forces of all principal tests and prescribed number of cycles of the cyclic test, for test loading levels P2 (see 16.2 and 16.3) 115

Table G.3 — Test forces of all separate tests on ankle-foot devices and foot units and prescribed number of cycles of the cyclic test, for test loading levels P2 (see 17.2) 116

G.5 Specification of different test loading conditions and test loading levels for principal cyclic tests for loading level P2 117

Table G.4 — Values of ankle and knee moments related to test force F = F_cr for different test loading conditions and test loading levels of principal cyclic tests for Test Range 3 (R3) 117

Table G.5 — Calculated values of axial force and twisting moment related to test force F = F_cr for different test loading conditions and test loading level P2 of principal cyclic tests for Test Range 3 (R3) 118

Table G.6 — Values of ankle and knee moments related to test force F = F_cmax for different test loading conditions and test loading level P2 of principal cyclic tests for Test Range 3 (R3) 118

Table G.7 — Calculated values of axial force and twisting moment related to test force F = F_cmax for different test loading conditions and test loading level P2 of principal cyclic tests for Test Range 3 (R3) 118

Annex H (informative) Alternative test geometry for loading condition I and II derived from recent biomechanical studies 119

H.1 Background statement 119

Table H.1 — Values of offsets for all principal tests in the proposed alternative test geometry (see 16.2 and 16.3) 119

Table H.2 — Test forces for increased factor of safety with alternative test geometry for cyclic tests 120

Annex ZA (informative) Relationship between this European standard and the General Safety and Performance Requirements of Regulation (EU) 2017/745 aimed to be covered 121

Bibliography 124

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

ISO draws attention to the possibility that the implementation of this document may involve the use of patent. ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, ISO had not received notice of patents which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.

Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO's adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 168, Prosthetics and orthotics.

This third edition cancels and replaces the second edition (ISO 10328:2016), which has been technically revised.

The main changes are as follows:

— Offsets for P3 and P4 are combined into the test offset for P5 in Table 7 and have been removed from document. Outward offset at bottom reference plane has been changed from -19 mm to +19 mm to align with results from modern gait analysis. Outwards offsets knee and ankle have been adjusted accordingly.

— Test load levels P6 through P8 previously in former Annex D have been included in Tables 5, 9 and 12 and the Annex removed from the document. Former Annex E and F have been renamed to Annex D and E and references updated. Former Annex G has been removed. New Annex F, Annex G, Annex H and Annex ZA have been added.

— Test Ranges (R) for the strength test have been introduced, related to the intended use of the device. The ranges differ by different loading factors, while tests load levels remain unchanged apart from rounding and accommodation to changed offsets (see below).

— Test forces in Table 12 have been adjusted for P3 and P4.

— A method to analyse shock absorption capacity has been added, which eliminates the difficulty to decide whether a device passes or fails above the ultimate static lower load level.

— Separate tests on knee locks are now optional tests and the test methods on separate tests on knee locks have been removed from the document.

— Test geometry of this document is limited to 150mm above knee-joint centre.

— Section 21 has been renamed to Compliance to Standard and reference to Labelling has been removed from the document.

— Table 2, Table 5, Table 6, Table 7, Table 8, Table 9, Table 10, Table 11 and Table 12 have been updated and forces adjusted for new unified offsets.

— Table B.1, Table B.2, Table B.3 and Table B.4 have been updated.

— The rate of loading of between 100 N/s and 10 kN/s is now normative.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

Throughout this document, the term prosthesis means an externally applied device used to replace wholly, or in part, an absent limb segment.

As a result of concern in the international community about the need to provide prostheses that are safe in use, and also because of an awareness that test standards would assist the development of better prostheses, a series of meetings was held under the aegis of the International Society for Prosthetics and Orthotics (ISPO). The final one was held in Philadelphia, PA, USA in 1977 at which a preliminary consensus was reached on methods of testing and the required load values. From 1979 onwards this work was continued by ISO Technical Committee 168 leading to the development of ISO 10328:1996. The test procedures may not be applicable to prostheses of mechanical characteristics different from those used in the consensus.

During use, a prosthesis is subjected to a series of load actions, each varying individually with time. The test methods specified in this document use static and cyclic strength tests which typically produce compound loadings by the application of a single test force.

The static tests relate to the worst loads generated in any activity. The cyclic tests relate to normal walking activities where loads occur regularly with each step. This document specifies fatigue testing of structural components. The tests specified do not provide sufficient data to predict actual service life.

The evaluation of lower-limb prostheses and their components requires controlled field trials in addition to the laboratory tests specified in this document.

The laboratory tests and field trials should be repeated when significant design changes are made to a load-bearing part of a prosthesis.

Ideally, additional laboratory tests should be carried out to deal with function, wear and tear, new material developments, environmental influences and user activities as part of the evaluation procedure. There are no standards for such tests, so appropriate procedures will need to be determined.

Prosthetics — Structural testing of lower-limb prostheses — Requirements and test methods

WARNING — This document is not suitable to serve as a guide for the selection of a specific lower limb prosthetic device/structure in the prescription of an individual lower limb prosthesis! Any disregard of this warning can result in a safety risk for amputees.

This document specifies procedures for static and cyclic strength tests on lower-limb prostheses (see NOTE 2) which typically produce compound loadings by the application of a single test force. The compound loads in the test sample relate to the peak values of the components of loading which normally occur at different instants during the stance phase of walking.

This document specifies Test Ranges (R) by specifying locomotion profiles for the cyclic test in relation to the intended use. According to the concept of the tests of this document, each sample of lower limb prosthetic device / structure submitted for test is, nevertheless, free to develop its individual performance under load.

The tests described in this document comprise

— principal static and cyclic tests for all components;

— a separate static test in torsion for all components;

— separate static and cyclic tests on ankle-foot devices and foot units for all ankle-foot devices as single components including ankle units or ankle attachments and all foot units as single components;

— a separate static ultimate strength test in maximum knee flexion on knee joints and associated parts for all knee units or knee-shin-assemblies and adjacent components that normally provide the flexion stop on a complete prosthesis;

— optional separate tests on knee locks for all mechanisms which lock the knee joint in the extended position of the knee unit or knee-shin-assembly.

The tests described in this document apply to specific types of ankle-disarticulation prostheses (see NOTE 2), to transtibial (below-knee), knee-disarticulation and transfemoral (above-knee) prostheses and to the distal (lower) part of hip-disarticulation and hemi-pelvectomy prostheses (see NOTE 3). The test geometry described in this standard is only intended to be used up to a level of 150 mm above the knee-joint centre.

This document is suitable for the assessment of the conformity of lower limb prosthetic devices/structures with the strength requirements specified in 4.4 of ISO 22523:2006 (see NOTE 1). Lower limb prosthetic devices/structures on the market, which have demonstrated their compliance with the strength requirements specified in 4.4 of ISO 22523:2006 through submission to the relevant tests of ISO 22523:2006, need not be retested to this document.

NOTE 1 The tests can be performed on complete structures, on part structures or on individual components.

NOTE 2 The tests only apply to ankle-disarticulation prostheses which include (foot) components of prosthetic ankle-foot devices taken from the normal production line.

NOTE 3 The distal part comprises the knee unit, the ankle-foot device and all parts between. Tests on hip units are described in ISO 15032.

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 7000, Graphical symbols for use on equipment — Registered symbols

ISO 8549‑1, Prosthetics and orthotics — Vocabulary — Part 1: General terms for external limb prostheses and external orthoses

ISO 22675:2024, Prosthetics — Testing of ankle-foot devices and foot units — Requirements and test methods

ISO 22523:2006, External limb prostheses and external orthoses — Requirements and test methods

IEC 60417, Graphical symbols for use on equipment

For the purposes of this document, the terms and definitions given in ISO 8549-1 and the following apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp

— IEC Electropedia: available at https://www.electropedia.org/

3.1

proof strength

static load representing an occasional severe event, which can be sustained by the prosthetic device/structure and still allow it to function as intended

3.2

ultimate strength

static load representing a gross single event, which can be sustained by the prosthetic device/structure but which could render it thereafter unusable

3.3

fatigue strength

cyclic load which can be sustained by the prosthetic device/structure for a given number of cycles

3.4

batch

set of test samples of a prosthetic device/structure submitted together to a test laboratory/facility to undertake tests to demonstrate conformity with requirements

3.5

shock absorption capacity

capacity of a specimen to absorb energy by deflection without a proportional increase of force

3.6

test force

force applied to a sample under test

The designations and symbols of all relevant test forces and moments are listed in Table 1.

Table 1 — Designations and symbols of test forces and moments

5.1 A lower limb prosthetic device/structure shall have the strength to sustain the loads occurring during use by amputees in the manner intended by the manufacturer for that device according to his written instructions on its intended use in accordance with ISO 22523:2006, 4.4.1. Based on the written instructions for use, the manufacturer/submitter assigns a Test Range (R) that is appropriate to test the strength of the device for the intended use. The manufacturer / supplier is responsible for the instructions for use and the related assignment. National or international classification schemes are independent to the instructions and the related assignment. For the assessment of the strength to sustain loads occurring during use, this document provides a means of determining the four categories of strength. These are listed in Table 2, together with the related performance requirements and the test methods for their verification.

5.2 In order to demonstrate the strength to sustain the loads occurring during use by amputees of a specific lower limb prosthetic device/structure, the following safety concept shall apply.

The device/structure shall

a) comply with the requirements in 9.1, 9.2 and 9.3 and for a specific test loading level the requirements in 7.2.

and

b) be used in accordance with the body mass limit specified by the manufacturer in consideration of the intended use of that device (see NOTE).

and

c) be used solely for the intended use as described in the instructions for use..

The conditions in a), b) and c) are regarded in both the classification and designation of prosthetic devices/structures according to Clause 20 and their identification according to Clause 21.

NOTE The statement of the body mass limit not to be exceeded by amputees is part of the conditions of use to be specified, with justification, by the manufacturer in his written instructions on the intended use of a specific lower limb prosthetic device/structure, taking account of all other factors affecting the loads expected to be exerted on that lower limb prosthetic device/structure by amputees (see Clause B.1).

Table 2 — Categories of strength addressed in this document,
together with the related performance requirements and test methods for their verification

6.1.1 For ease in interpretation and presentation, two test configurations are specified, one for right-sided and a mirror image for left-sided application. This measure makes it possible to apply uniform sign conventions for corresponding components of loading generated in the load-bearing structures of right and left prostheses or in asymmetrically designed prosthetic components.

6.1.2 Each test configuration shall be defined in a three-dimensional, rectangular coordinate system (see Figure 1), having an origin 0 and containing a geometric system of planes, lines and points (see Figures 2 and 3).

6.1.3 Each test configuration specifies reference parameters both for the position of the line of application of the test force and for the alignment of test samples within the coordinate system.

6.2.1 The axes of each of the coordinate systems are specified in 6.2.2 to 6.2.4 in relation to a prosthesis which is standing on the ground in an upright position.

If a test sample is not in the upright position, the axes of the coordinate system shall be rotated to correspond.

6.2.2 The u-axis extends from the origin 0 of the coordinate systems (see Figure 1) and passes through the effective ankle-joint centre and the effective knee-joint centre (see 6.7.3 and 6.7.6 as well as Figure 6). Its positive direction is upwards (in the proximal direction).

6.2.3 The o-axis extends from the origin 0 perpendicular to the u-axis (see Figure 1) and parallel to the effective knee-joint centreline (see 6.7.5 and Figure 6). Its positive direction is outward (in the lateral direction), which is to the left for a left prosthesis and, with the related mirrored values, to the right for a right prosthesis.

6.2.4 The f-axis extends from the origin 0 perpendicular to both the o-axis and the u-axis (see Figure 1). Its positive direction is forward towards the toe (in the anterior direction).

The reference planes (see Figures 2 and 3) shall be parallel planes perpendicular to the u-axis. They are specified in 6.3.2 to 6.3.5.

NOTE The reference planes specified in 6.3.2 to 6.3.5 also contain reference lines which relate to Annex B.

The top reference plane, T, is located at a distance u = u_T from the origin. It contains the top load application point P_T (see 6.4).

The knee reference plane, K, is located at a distance u = u_K from the origin. It contains the knee load reference point P_K (see 6.4) and the effective knee-joint centre (see 6.7.6).

The ankle reference plane, A, is located at a distance u = u_A from the origin. It contains the ankle load reference point P_A (see 6.4) and the effective ankle-joint centre (see 6.7.3).

NOTE Connectors or ankle-joint units, connecting the ankle-foot unit to proximal elements, can be located in positions different to the effective ankle-joint centre.

The bottom reference plane, B, is located at a distance u = u_B from the origin. It contains the bottom load application point P_B (see 6.4).

Key

1 right

2 left

0 origin

f forward

o outward

u upward

Figure 1 — Coordinate systems for right and left-sided application

Key

1 right

2 left

3 top reference plane, T

4 knee reference plane, K

5 ankle reference plane, A

6 bottom reference plane, B

Figure 2 — Coordinate systems according to Figure 1 with reference planes

Key

1 right leg

2 left leg

3 top reference plane, T

4 load line

5 knee reference plane, K

6 ankle reference plane, A

7 bottom reference plane, B

P_T top load application point

P_K knee load reference point

P_A ankle load reference point

P_B bottom load application point

NOTE This figure illustrates a typical test loading condition representative of the condition of forefoot loading during the stance phase of normal walking. It does not illustrate the test loading conditions defined in 7.1.2.

Figure 3 — Specific configuration with u_B = 0, showing coordinate systems with reference planes
(see Figures 1 and 2), reference lines, reference points and test force, F,
for right and left-sided application

The reference points are the points of intersection of the load line (see 6.6) with the reference planes (see Figure 3). The coordinates of the reference points are as follows:

In the subsequent clauses of this document, the f- and o-coordinates are also referred to as OFFSETS (see also 6.8.1).

The test force, F, is a single compressive load applied to the bottom and top load application points P_B and P_T specified in 6.4.

The load line is the line of application of the test force, F. It passes through the reference points specified in 6.4.

In order to align the test sample within the appropriate coordinate system (see 6.1 to 6.3) it is necessary to locate

a) the longitudinal axis of the foot (see 6.7.2);

b) the effective ankle-joint centre (see 6.7.3);

c) the effective ankle-joint centreline (see 6.7.4);

d) the effective knee-joint centreline (see 6.7.5);

e) the effective knee-joint centre (see 6.7.6).

If the location of the longitudinal axis of the foot or any effective joint centre or effective joint centreline is not obvious, the manufacturer/submitter shall provide a diagram or instructions, with justification, identifying its location in relation to the test sample.

Unless otherwise specified by the manufacturer/submitter, the longitudinal axis of the foot shall be taken to pass through the centre of the widest part of the forefoot and equidistant between the medial and lateral borders of the foot at a quarter of the length of the foot from the most posterior part of the foot with the foot placed as specified in 6.7.3.3 and illustrated in Figure 4.

6.7.3.1 Locate the effective ankle-joint centre as described in 6.7.3.2 to 6.7.3.4. See also note in 6.2.2.

NOTE The position of a mechanical axle for plantar- and dorsiflexion (if present) is irrelevant to the alignment of the test sample within the appropriate coordinate system.

6.7.3.2 Locate the longitudinal axis of the foot as described in 6.7.2 or in accordance with any specific instruction from the manufacturer/submitter.

6.7.3.3 Place the foot on a horizontal surface with a block of the manufacturer’s/submitter’s recommended heel height h_r placed under the heel of the foot (see Figure 4).

Unless otherwise specified by the manufacturer/submitter the recommended heel height for the ankle-foot device or foot unit under test is taken as hr = 20 mm.

Key

1 effective ankle-joint centre

2 effective ankle-joint centreline

3 longitudinal axis of foot corresponding to 6.7.2

h_r heel height

L foot length

P_B bottom load application point on forefoot (test loading condition II)

S_B combined bottom offset of bottom load application point P_B on forefoot from u-axis

Figure 4 — Determination of longitudinal axis of foot (see 6.7.2), effective ankle-joint centre (see 6.7.3) and effective ankle-joint centreline (see 6.7.4) for test loading conditions I and II and of combined bottom offset S_B (see 6.8.2) for test loading condition II [see 7.1.2 b)]

6.7.3.4 The effective ankle-joint centre is located

a) in a vertical plane passing through the longitudinal axis of the foot;

b) in the ankle reference plane located 80 mm above the bottom reference plane, i.e. 80 mm above the horizontal line passing through P_B;

c) at a quarter of the length of the foot from the most posterior part of the foot.

NOTE Connectors or ankle-joint units, connecting the ankle-foot unit to proximal elements, can be located in positions different to the effective ankle-joint centre.

The effective ankle-joint centreline shall be the horizontal line passing through the effective ankle-joint centre (see 6.7.3) perpendicular to the longitudinal axis of the foot (see 6.7.2).

6.7.5.1 For a monocentric knee unit which has no knee lock or stance phase control mechanism, the effective knee-joint centreline shall coincide with the joint flexion axis [see Figure 5 a), b) and c)].

This shall also apply to a monocentric knee unit with a knee lock or a stance phase control mechanism which allows walking when these are disengaged.

6.7.5.2 For all knee units not covered by 6.7.5.1, the effective knee-joint centreline shall be established from the manufacturer’s/submitter’s written alignment instructions for the knee unit [see Figure 5 d) and e)].

Key

1 orientation 1 = posterior (toward the rear)

2 orientation 2 = anterior (toward the front)

Figure 5 — Position of effective knee-joint centreline for prosthetic knee units of different types

6.7.6.1 The effective knee-joint centre shall lie on the effective knee-joint centreline.

6.7.6.2 For symmetrical knee units, the effective knee-joint centre shall be the point on the effective knee-joint centreline equidistant from the external boundaries of the unit.

6.7.6.3 For asymmetrical or handed knee units, the position of the effective knee-joint centre shall be established from the manufacturer’s/submitter’s written alignment instructions for the knee unit.

The offsets shall be the perpendicular distances of the reference points specified in 6.4 from the o-u plane and the u-f plane of the coordinate systems specified in 6.1 and 6.2. Their values are identical with the corresponding f- and o-coordinates of these reference points.

The combined offsets S_B, S_A, S_K and S_T shall be the perpendicular distances of the reference points P_B, P_A, P_K and P_T specified in 6.4 from the u-axis of the coordinate systems specified in 6.1 and 6.2.

NOTE S_B is also addressed in 10.1.2 and illustrated in Figures 4 and 6 for test loading condition II defined in 7.1.2 b).

The effective lever arms are the perpendicular distances of the effective joint centres from the load line, where L_A represents the ankle effective lever arm length and L_K the knee effective lever arm length.

L_BT shall be the distance between the bottom load application point P_B and the top load application point P_T (see 6.4).

The complexity of the load actions to which a lower-limb prosthesis is actually subjected during use by the amputee cannot be simulated by a single test procedure. Therefore, several types of static and cyclic strength tests are specified in the two categories “Principal structural tests” (Clause 16) and “Separate structural tests” (Clause 17), each type of test applying a single or two different test loading condition(s) (see 7.1.2 and 7.1.3).

Each test loading condition is characterized by a specific test load acting along or about a specific line of load application and producing axial compression, shear forces, bending moments and/or torque as single components of loading or compound loadings.

The test loading condition(s) for each type of test are addressed in Table 15 and specified in the relevant Tables 4 to 13. Further details are given in the relevant test procedures, specified in Clause 16 and 17.

NOTE For further information see also Annexes A and B.

The loading of the static and cyclic principal structural tests specified in 16.2 and 16.3 shall be applied in two different test loading conditions I and II relating to the maxima occurring at different instants during the stance phase of normal walking as described in a) and b). For both test loading conditions the position of the line of load application (see 7.1.1) within the coordinate system (see 6.1 and 6.2) shall be three-dimensional (see Figures 3, 6 and 11). The specific values of offsets, combined offsets and test forces for each test loading condition and each principal structural test are specified in Tables 7, 8 and 9.

a) Test loading condition I is related to the instant of maximum loading occurring early in the stance phase of walking.

b) Test loading condition II is related to the instant of maximum loading occurring late in the stance phase of walking.

Test loading condition of the separate static test in torsion

The loading of the separate static test in torsion specified in 17.1 shall be applied as torque about the u-axis (see 6.2.2) first in one direction and then in the other direction. The specific values of torque are specified in Table 10.

Test loading conditions of the separate tests on ankle-foot devices and foot units

The loading of the separate static and cyclic tests on ankle-foot devices and foot units specified in 17.2 shall be applied in two different test loading conditions simulating heel loading in the direction determined by the angle α and forefoot loading in the direction determined by the angle β. For both test loading conditions the position of the line of load application (see 7.1.1) within the coordinate system (see 6.1 and 6.2) shall be two-dimensional (see Figure 7). The specific values of angles and forces for each test loading condition and each test are specified in Tables 11 and 12.

Test loading condition of the separate static ultimate strength test in maximum knee flexion for knee joints and associated parts

The loading of the separate static ultimate strength test in maximum knee flexion on knee joints and associated parts specified in 17.3 shall be applied in a single test loading condition simulating kneeling or squatting (deep knee bend). The position of the line of load application (see 7.1.1) within the coordinate system (see 6.1 and 6.2) shall be two-dimensional (see Figure 8). The specific values of length and test force are specified in Table 13.

Test loading condition of the optional separate tests on knee locks

Separate static and cyclic tests on knee locks are optional. The manufacturer/submitter specifies offsets and test loads in the submission document based on the intended use and the knees are tested accordingly.

7.2.1 The load actions referred to in 7.1.1 vary with individual physical parameters, locomotion characteristics of the amputee and other factors. For these reasons different categories of prostheses are needed and, consequently, different test loading levels are required, each being specified by individual values of dimensions and loads.

The series P test loading levels designated as given in 7.2.3 shall apply to lower limb prostheses for adults.

NOTE For further information see Annex B.

7.2.2 The specification of the test loading conditions of each of the test loading levels listed in 7.2.3 is governed by a safety concept, characterized in the following manner (see also Table 4 and Table 9).

— The values of test force, F_cr, of the principal cyclic test according to 16.3.2 are set at a level which covers the full range of load actions disclosed by the locomotion data acquired from the group of amputees representative of the relevant test loading level (see Annex B); the values of the test forces, F_1cr and F_2cr, of the separate cyclic test for ankle-foot devices and foot units according to 17.2.5 are set correspondingly.

— The corresponding values of the test forces, F_sp and F_su, of the principal static tests according to 16.2.1 and 16.2.2, the test forces, F_1sp/F_2sp and F_1su/F_2su, of the separate static tests for ankle-foot devices and foot units according to 17.2.3 and 17.2.4 are calculated by application of factors as specified in Table 4; the values of the twisting moment, M_umax, of the separate static test in torsion according to 17.1 and the test force, F_su, of the separate static ultimate strength test in maximum knee flexion according to 17.3 are set correspondingly.

— The specification of all test forces takes account of records on component failures of lower limb prostheses, taken in clinical or technical service.

7.2.3 Designation of test loading levels for adults is given below.

Test loading levels: P3, P4, P5, P6, P7 and P8

NOTE The values of the dimensions and loads of test loading levels P3, P4, P5, P6, P7 and P8 are specified in separate tables in Clause 8. Further test loading levels will be defined, if necessary.

7.2.4 Description of Test Ranges (R) for adults is given below.

The test parameter that is varied for the ranges is the force (see Table 9 and Table 12) to emulate the biomechanical parameters and activities of Test Ranges R2, R3 and R4 defined in Table 3.

Background Data about the average walking speed addressed in Table 3 is given in Annex F.

If a patient range assignment is uncertain, always use the next higher Test Range (R).

In absence of an accurate biomechanical assessment, Test Range R4 should be used.

Table 3 — Average walking speed and Description/Activities related to Test Ranges (R)

Forces and twisting moments; segmental lengths, offsets and angles; prescribed number of cycles are addressed.

Tables 4 to 13 describe and/or specify the values of

— test forces and twisting moments,

— dimensions such as segmental lengths, offsets and angles and

— load factor, prescribed factor to multiply tabulated test forces with, based on the Test Range (R)

— cycles (prescribed number of loading cycles).

Table 4 — Test loads and relevant references<Tbl_-></Tbl_->

Table 5 — Test forces of the proof test of end attachments for all test loading levels P3, P4, P5, P6, P7 and P8 (see 13.2.1.2)

Table 6 — Total length and segmental lengths of different types of test samples for principal tests and separate tests on knee locks, for all test loading conditions and
all test loading levels P3, P4, P5, P6, P7 and P8
(see also 10.2, 10.3, 16.2, 16.3, 17.4 and Figure 2)<Tbl_-></Tbl_->

Dimensions in millimetres

Table 7 — Values of offsets for all principal tests (see 16.2 and 16.3)<Tbl_-></Tbl_->

Dimensions in millimetres

Table 8 — Values of combined offsets related to the values of offsets listed in Table 7 (see 10.1.2 and 13.2.1.2.3)<Tbl_-></Tbl_->

Dimensions in millimetres

Table 9 — Test forces of all principal tests and prescribed number of cycles of the cyclic test,
for all test loading levels P3, P4, P5, P6, P7 and P8
(see 16.2 and 16.3)

Table 10 — Twisting moments of the separate static test in torsion for all test loading levels P3, P4, P5, P6, P7 and P8 (see 17.1)<Tbl_-></Tbl_->

Table 11 — Angles of directions of loading of all separate tests on ankle-foot devices and foot units, for all test loading levels P3, P4, P5, P6, P7 and P8
(see 17.2 and Figure 7)<Tbl_-></Tbl_->

Table 12 — Test forces of all separate tests on ankle-foot devices and foot units and prescribed number of cycles of the cyclic test, for all test loading levels P3, P4, P5, P6, P7 and P8
(see 17.2)<Tbl_-></Tbl_->

Table 13 — Loading parameters of the separate static ultimate strength test in maximum knee flexion for knee joints and associated parts for all test loading levels P3, P4, P5, P6, P7 and P8
(see 17.3 and Figure 8)<Tbl_-></Tbl_->

In order to claim compliance with this document for a prosthetic device/structure submitted for test, a prescribed number of test samples of this structure from the allowed batch, specified in Table 15, shall satisfy the relevant requirements of Clauses 9, 10, 16 and 17 and the relevant test loading conditions and test loading levels of Clauses 7 and 8. Any claim of compliance shall state the test loading level and the Test Range (R) at which tests were conducted.

Compliance of a prosthetic device/structure submitted for test with the performance requirements of a specific test of this document required (see 9.2) shall be certified by the test laboratory/facility only for the specific prosthetic assembly and alignment simulated in the set-up of the batch of test samples of the prosthetic device/structure which have been subjected to this test (see 9.4).

Compliance demonstrated for devices subjected to a higher Test Range (R), also covers lower Test Ranges (R) at identical P-level.

NOTE The manufacturer/submitter may claim compliance also for other prosthetic assemblies and/or alignments in which the prosthetic device/structure submitted for test can be used, provided it can be certified that these lie within the range of loading covered by the most adverse assembly and the worst-case alignment simulated in the test sample set-up of the prosthetic device/structure submitted for test.

The different combinations of principal and separate structural tests, required to be completed on test samples of prosthetic structures submitted for test representing complete assemblies, partial assemblies or individual components (see Clause 10) to claim their compliance with this document, are indicated in Table 14.

For batches of test samples of prosthetic structures submitted for test including an ankle-foot device or foot unit, the claim of compliance with this document requires that the ankle-foot device or foot unit satisfy the requirements of the separate tests on ankle-foot devices and foot units specified in 17.2, independent of other tests required to claim compliance with this document, which also may involve/load the ankle-foot device or foot unit.

In order to claim compliance with this document, for a prosthetic structure submitted for test including an ankle-foot device or foot unit that is detachable:

— samples of this ankle-foot device or foot unit from the permitted batch (see Table 15) shall be subjected only to the separate tests on ankle-foot devices and foot units specified in 17.2.

while

— the samples of the remainder of the prosthetic structure shall be subjected to the principal structural tests specified in 16.2 and 16.3 with the ankle-foot device or foot unit replaced by a rigid lever arm (bottom load application lever).

9.3.3.1 In order to claim compliance with this document for a prosthetic structure submitted for test including an ankle-foot device or foot unit that is detachable, batches of the part required to connect the ankle-foot device or foot unit to the remainder of the prosthetic structure, such as an ankle-unit, ankle attachment, alignment device or pylon base, shall be tested in either of the ways specified in 9.3.3.2 and 9.3.3.3.

9.3.3.2 If the manufacturer/submitter intends to claim compliance with this document for a specific assembly of connecting part and ankle-foot device or foot unit or for specified assemblies of the connecting part and several types of ankle-foot device or foot unit, then batches of samples of each specific assembly shall be subjected to the separate tests on ankle-foot devices and foot units specified in 17.2.

9.3.3.3 If the manufacturer/submitter intends to claim compliance with this document for assemblies of the connecting part and any type of ankle-foot device or foot unit in accordance with the NOTE in 9.1, then batches of samples of this part shall be subjected to the principal structural tests specified in 16.2 and 16.3 in a test sample set-up in which the foot unit is replaced by a rigid lever arm, in order to apply the longest effective lever arm possible corresponding to the requirements of 10.3.4.

The minimum number of tests required for each type of test in the prescribed loading conditions in order to claim compliance with this document is shown in Table 15.

The tests shall be conducted on test samples from the batch specified in Table 15 for each type of test.

The minimum number indicates how many test samples of a prosthetic device/structure submitted for test shall complete the tests without failing.

All tests shall be conducted in the worst-case alignment position of the test samples (see 10.6) and, if these include partial structures according to 10.2.2 which can be used in various prosthetic assemblies, in the most adverse prosthetic assembly possible (see 10.3.4).

NOTE The total number of test samples actually needed for the conduct of a selection of specific types of tests relevant to the prosthetic device/structure submitted for test may differ from the total calculated by addition of the number of test samples specified in Table 15 for each of the types of tests selected, since the number of substitutes needed may vary, and since test samples that have completed a specific test without failing may be used for another test (see 9.5, 16.2.1.1.2, 16.2.2.1.2, 17.2.4.1.2, 17.2.4.1.2).

Test samples, which have demonstrated compliance with the performance requirements of any of the tests specified in this document, may be subjected to other tests of this document, except as stated in 9.5.2.

Any decision on the multiple use of test samples shall be based on a corresponding indication in the test submission document (see Clause 12) and/or the agreement between the manufacturer/submitter and the test laboratory/facility.

As a general rule, any failure occurring during a test on a test sample that has previously been subjected to another test justifies the repetition of the failed test on a substitute test sample (see Table 15).

NOTE The multiple use of test samples is specifically addressed in the principal static tests (16.2.1 and 16.2.2), the separate static tests for ankle-foot devices and foot units (17.2.3 and 17.2.4) and the optional separate static tests for knee locks (17.4) – (see also references in the NOTE in 9.4).

Unless otherwise indicated in the test submission document and/or agreed between the manufacturer/submitter and the test laboratory/facility, this document does not stipulate that the tests required to claim compliance for the prosthetic device/structure submitted for test be conducted in a particular order, with the exception of the restriction specified in 9.5.2.

Compliance of any test sample with the performance requirements of any of the cyclic tests of this document cannot be claimed if the test sample has previously been subjected to any of the static ultimate strength tests of this document.

For different reasons the intended use of a particular design of a lower limb prosthetic device/structure can require the tests of this document to be applied at a particular test loading level not specified in this document, derived from the next lower regular test loading level of this document by increasing its test loads by x %.

In this case compliance with this document cannot be claimed for that particular test loading level.

However, compliance with this document may be claimed for the next lower or a lower regular test loading level of this document, from which that particular test loading level has been derived.

Reference to this document can also be given by stating that the prescribed batch (or batches) of test samples of a prosthetic device/structure submitted for test has (have) been tested

a) following this document

or in a more specific manner

b) by applying the tests of this document at test loads set x % above test loading level P_y.

Table 14 — Tests required to claim compliance with this document for prosthetic structures representing complete assemblies, partial assemblies or individual components<Tbl_-></Tbl_->

Table 15 — Number of tests and test samples required to claim compliance
with this document<Tbl_-></Tbl_->

The test samples of prosthetic devices/structures selected for test shall be taken from normal production. Details of the selection shall be recorded in the test submission document (see Clause 12). If the manufacturer/submitter supplies a certificate stating that the test sample has been taken from the normal production line, this certificate shall be included in the test submission document, together with details of the sampling method.

NOTE Test samples of prosthetic devices/structures can also be submitted for specific tests by any interested party.

10.1.2.1 For principal structural tests on samples of prosthetic structures including an ankle-foot device or a foot unit that forms an integral part of the structure and cannot be detached (see 9.3), the size of the foot selected shall allow the application of load in accordance with the combined bottom offset S_B specified for the test (see 6.8.2, Table 8 and Figures 4 and 6), S_B being determined by the formula

(1)

where f_B and o_B are the f- and o-offsets of the bottom load application point P_B.

The selection of the size of the foot and possible subsequent adaptations of the test force shall be carried out as follows:

a) select a size that gives the correct combined bottom offset, S_B;

b) if a correct size foot is not available, use the next larger size;

c) if the foot available is shorter than the correct length, then increase the applied test force F to F' where:

(2)

and where

10.1.2.2 For separate structural tests on ankle-foot devices and foot units on samples of prosthetic structures including an ankle-foot device or a foot unit that can be detached or on samples comprising an ankle-foot device or a foot unit as a single component, the size of the foot selected shall provide the worst-case loading (see note) that is possible for that type of foot when subjected to the heel and forefoot loading specified for the test (see Tables 11 and 12).

The size of foot providing the worst-case loading shall be determined by the manufacturer/submitter (see NOTE) and shall be stated, with justification, in the test submission document (see Clause 12).

NOTE The determination of the size of foot providing the worst-case loading can be based on design features, on findings of risk management and/or on the results of appropriate preliminary tests conducted on feet of different size.

An appropriate measure for the worst-case loading is the direction and magnitude of the ankle (A-P) bending moment (see Annex A), generated by the test forces applied to the heel and forefoot of the ankle-foot device or foot unit and determined by the lengths of the effective lever arms on which these test forces act.

Although there is a fundamental relationship between the lengths of the effective lever arms and the size of the foot, the worst-case loading need not necessarily be provided in each case by the largest size of foot available for the test loading level to be applied, but can also be influenced by other design parameters.

10.2.1.1 For a knee-disarticulation or a transfemoral (above-knee) prosthesis, a complete structure consists of a knee unit and ankle unit or ankle attachment with all parts between. It may also contain parts above the knee unit, including the socket (see 10.2.1.4), and below the ankle unit or ankle attachment, including the foot unit.

10.2.1.2 For the distal part of a hip-disarticulation (or hemi-pelvectomy) prosthesis, a complete structure consists of a knee unit and ankle unit or ankle attachment with all parts between. It may also contain parts below the ankle unit or ankle attachment, including the foot unit.

NOTE Tests of components of hip-disarticulation (or hemi-pelvectomy) prostheses which are above the level of the knee are specified in ISO 15032.

10.2.1.3 For a transtibial (below-knee) prosthesis, a complete structure consists of the ankle unit or ankle attachment and the socket attachment with all parts between. It may also contain parts above the socket attachment, including the socket (see 10.2.1.4), and below the ankle unit or ankle attachment, including the foot unit.

10.2.1.4 The mechanical connection between a transtibial (below-knee), knee-disarticulation or transfemoral (above-knee) socket and the distal shin-socket or knee-socket attachment is a critical region of a prosthetic structure.

In order to demonstrate that this connection has the strength required to sustain the loads expected to occur during use by amputees in the manner intended, manufacturers shall submit complete structures, including the socket or a socket dummy, for test in accordance with the relevant requirements of this document.

10.2.1.5 An example of a complete structure of a left transfemoral (above-knee) prosthesis and its alignment within the coordinate system is shown in Figure 6.

Key

1 left foot

2 load line

3 effective knee-joint centre

4 effective knee-joint centreline

5 effective ankle-joint centre

6 effective ankle-joint centreline

P_K knee load reference point

P_A ankle load reference point

P_B bottom load application point

P_T top load application point

NOTE This figure illustrates a typical test loading condition representative of the condition of forefoot loading during the stance phase of normal walking. It corresponds to test loading condition II defined in 7.1.2 b).

Figure 6 — Application of a specific test configuration with u_B = 0
to a left-sided sample specified in 10.2.1

For any type of prosthesis, a partial structure is less than a complete structure and may be a single component, such as a knee unit or an ankle-foot device.

A specific example of a partial structure is a test sample of a foot unit or the structural parts of a foot unit used in specific types of ankle-disarticulation prostheses.

When a partial structure is tested, the end connections shall have mechanical characteristics similar to those of the intended adjacent components, unless otherwise specified in this document.

If the design of a leg structure does not allow it to be tested as a test sample in accordance with 10.2.1 or 10.2.2, then a special test set-up may be used for testing. For example, such a leg could be a one-piece flexible plastic structure that includes the foot.

If the manufacturer/submitter and the test laboratory/facility certify in writing in the test submission document (see Clause 12) and the test report (see Clause 19), that the effective geometry of the test sample and the test loading conditions comply with the requirements of Clauses 7, 8 and 16 or 17, as appropriate, then testing may be carried out and a test report issued in accordance with Clause 19, in which this compliance is specifically addressed.

If the test sample satisfies the requirements of the relevant clauses of this document, then compliance with these clauses can be claimed. The claim shall clearly indicate that the test sample complies with 10.2.3 of this document.

If the geometry of the test sample cannot be so certified, then compliance with these clauses cannot be claimed.

10.3.1 The samples shall include all parts normally fitted.

10.3.2 Any cosmetic components shall be omitted from the sample, unless they contribute to the structural strength.

10.3.3 Where any test sample includes a socket or socket dummy, the preparation of the test sample shall include the measures listed in a) to c).

a) The distal portion of the socket or socket dummy, into which the distal socket attachment device extends, shall either be a void or be filled with foam or soft materials, in order to allow this portion to deform freely under load.

b) The remaining proximal portion of the socket or socket dummy shall be connected rigidly to the top end attachment, consisting of the extension piece, as required, and the top load application lever.

The use of a mandrel as extension piece, anchored within the socket or socket dummy by means of rigid foam, has been found to be suitable.

c) For a transtibial (below-knee) socket or socket dummy, the position of the effective knee-joint centre and the direction of the effective knee-joint centreline shall be identified, based on anatomical features derived from the socket shape. This is necessary to allow the alignment of the socket as required (see 10.5 and 10.6).

It has been found to be suitable to transfer the effective knee-joint centreline to the socket by drilling holes through the medial and lateral socket wall in the direction of the effective knee-joint centreline, the holes to serve as guide for alignment pins of a jig.

10.3.4 Where any test sample includes a partial structure according to 10.2.2 which can be used in different prosthetic assemblies, then the test sample set-up shall be prepared in accordance with a) and b) and the test submission document (see Clause 12).

a) If the partial structure is intended to be allowed for free use in any prosthetic assembly, then the test sample set-up shall be prepared to represent the most adverse prosthetic assembly possible.

b) If the partial structure is intended to be allowed for limited use in specified prosthetic assemblies, then the test sample set-up shall be prepared to represent each prosthetic assembly specified.

10.3.5 Where any test sample includes any end fittings, then it shall be assembled in accordance with Clause 11 and the test submission document.

10.3.6 For the principal structural tests (see Clause 16) and the optional separate structural tests on knee locks (see 17.4), all test sample types according to 10.2 shall be given a fixed total length, using end attachments consisting of extension pieces and the load application levers.

The fixed total length shall be determined by the dimension u_T − u_B and shall be achieved by selecting either one of the combinations specified in Table 6 for different types of test sample (see 10.2) or any other relevant combination. The combination of segment lengths selected shall be recorded.

10.3.7 For the separate tests on ankle-foot devices and foot units, the ankle-foot device or foot unit, selected in accordance with 10.1.2, shall be submitted assembled by the manufacturer/submitter to the part connected to the remainder of the prosthesis such as an ankle unit, alignment device, pylon base, compliant structure or exoskeletal member. The type and identification of the part connected shall be recorded.

10.3.8 For the separate static ultimate strength test in maximum knee flexion for knee joints and associated parts (see 17.3.4), the test sample shall consist of the assembly of knee unit and associated parts that normally provides the knee flexion stop on a complete prosthesis, comprising

— sub-assemblies of knee units and adjacent components normally required for their attachment to the proximal and distal part of a prosthesis and/or their alignment within a prosthesis, and

— knee-shin-assemblies, including adjacent components required for their attachment to the proximal part of a prosthesis and/or their alignment within a prosthesis.

Parts outside the specific assembly may be substituted. The form of the specific assembly and any substituted parts shall be recorded.

If a specific knee unit or knee-shin-assembly can be used in conjunction with different attachment/alignment components, then the test sample set-up shall represent the assembly where the knee flexion stop point is nearest to the axis of rotation (monocentric design) or nearest to the instantaneous centre of rotation (polycentric design) of the knee unit or knee-shin-assembly at maximum knee flexion of the test sample. (This is in accordance with 10.3.4).

10.3.9 For the separate static ultimate strength test in maximum knee flexion for knee joints and associated parts, all test samples shall have extension pieces attached above and below the knee unit, to represent wholly or in part the thigh and shin portion (for details see 10.5.3.1). The lengths of these extension pieces shall be recorded.

The test laboratory/facility shall apply to each test sample an indelible, unique and traceable identification.

10.5.1.1 For the principal structural tests (see Clause 16) and the optional separate structural tests on knee locks (see 17.4), all test sample types specified in 10.2 shall be aligned within the appropriate coordinate system in accordance with 6.1 to 6.3, 6.7.3 to 6.7.6, 10.6, 14.3 a) to d), Tables 6 and 7 and the test submission document (see Clause 12).

10.5.2.1 Test samples of an ankle-foot device or foot unit shall be aligned within the appropriate coordinate system in accordance with 6.1 to 6.3, 6.7.2 to 6.7.4, 14.3 a) and d), Table 11 and the test submission document (see Clause 12).

The longitudinal axis of the foot (see 6.7.2) shall be turned by γ = 7° as shown in Figure 7 and specified in Table 11 to give a “toe out” position of the ankle-foot device or foot unit.

NOTE The test mechanism used to apply F₁ and F₂, each should allow low-friction motion in both tangential directions, realized e.g. by ball bearings.

Figure 7 — Position of foot in test requirement (see 10.5.2, 13.4 and 17.2)

10.5.3.1 In the initial test sample set-up with the knee unit fully extended, the extension pieces attached above and below the knee unit to represent wholly or in part the thigh and shin portion shall be aligned on the u-axis and perpendicular to the effective knee-joint centreline and shall provide a length, L_e, of 400 mm, measured from the effective knee-joint centre, in accordance with 6.2.2, 6.7.5, 6.7.6, 10.3.9, 14.3 a) and b), Table 13 and Figure 8).

10.5.3.2 If the alignment of the test sample is adjustable, it shall be set in the worst-case alignment position in accordance with 10.6.

Key

L_e length of thigh and shin portion

^a Effective knee-joint centre.

Figure 8 — Test configuration for the separate static ultimate strength test in maximum knee flexion on knee joints and associated parts
(see 10.5.3.1, 13.5 and 17.3.4)

10.6.1 All tests shall be conducted in the worst-case alignment position of the test samples as defined by the criteria specified in 10.6.2 to 10.6.4.

10.6.2 The structurally worst alignment position shall, if possible, be defined by the manufacturer/submitter in the test submission document (see Clause 12). It shall lie within the limitations of the manufacturer’s written instructions for the alignment of the limb as supplied with every component of the type.

10.6.3 Where the structurally worst position cannot be defined as required in 10.6.2, then the sample shall be adjusted so that it is moved 90 % of the distance from neutral alignment to extreme alignment. The adjustment shall be directed away from the load line so as to increase the effective lever arm (see 6.8.3).

10.6.4 For samples for the separate static ultimate strength test in maximum knee flexion on knee joints and associated parts, the worst-case alignment position is when the perpendicular distance of the axis of rotation (monocentric design) or the instantaneous centre of rotation (polycentric design) of the knee unit from the load line at maximum knee flexion of the test sample assembly reaches its maximum value (but see NOTE).

In order to ensure that the test sample reaches the highest possible value of knee flexion that can occur in a normal prosthesis, the structures representing the thigh and shin portion (including the extension pieces) shall be designed and/or arranged so that their posterior contour/shape and extension keep within the “reference” contour/shape determined by the smallest dimensions that are possible in accordance with the manufacturer’s instructions for the intended application(s) of the knee unit or knee-shin-assembly taking account of

— the type(s) of prosthesis (knee-disarticulation, transfemoral or hip-disarticulation prosthesis);

— the attachment of these assemblies to the proximal and distal part of the prosthesis;

— the alignment of the knee joint within the prosthesis;

— the intended use of these assemblies within a complete prosthesis by the envisaged group(s) of amputees.

NOTE In order to enlarge the free space on the posterior side of the test sample to allow the maximum value of knee flexion to be reached, it may be appropriate or necessary to start the adjustment of the alignment with the knee unit placed in a position of posterior displacement relative to the longitudinal axis of the structure representing the thigh and shin portion, which would have the opposite effect on the distance referred to in the first paragraph of 10.6.4, and then to re-adjust the alignment in a way which moves the knee unit from the position of posterior displacement in the anterior direction so as to increase this distance.

11.1 The manufacturer/submitter shall be responsible for the selection and assembly of the components to be tested including screw connection torque settings in accordance with the manufacturer's written instructions for the assembly of components as supplied with every component of the type.

Correct tightening torque setting is of particular importance for the bolts of clamped connections regarding security against slippage, which is tested in the separate static test in torsion (see 17.1.3.1).

11.2 The manufacturer/submitter shall be responsible for the provision with the test sample of specified parts to be replaced when the number of cycles of the principal cyclic test and the optional separate cyclic test for knee locks has reached a value at which such replacement is indicated [see 16.1.3.2/16.3.2.16, 17.2.5.1.2 a)/17.2.5.1.9].

11.3 The manufacturer/submitter shall be responsible for preparing the test submission document in accordance with Clause 12.

11.4 The manufacturer/submitter or the test laboratory/facility shall be responsible for the attachment of the end attachments required for the principal structural tests and the optional separate tests on knee locks (see 13.2.1 and 13.6.1) and the extension pieces required for the separate static ultimate strength test in maximum knee flexion on knee joints and associated parts (see 13.5.1).

Whoever assembles them shall be responsible for their static alignment in accordance with

— 10.5.1 for the principal structural tests;

— 10.5.3 for the separate static ultimate strength test in maximum knee flexion on knee joints and associated parts;

— 10.5.1 and 10.5.4 for the optional separate tests on knee locks.

11.5 The test laboratory/facility shall be responsible for the verification that the test sample is assembled in accordance with Clause 10, the test submission document (see Clause 12) and the manufacturer’s/submitter’s written instructions supplied with every component of the type.

If the test sample assembly is not correct the test laboratory/facility shall, in consultation with the manufacturer/submitter, alter it to the specified configuration.

11.6 The test laboratory/facility shall be responsible for adjustment of the alignment to give the correct offsets and effective lever arms during test, in accordance with

— 10.5.1 for the principal structural tests (see also 16.2.1.1.2/16.2.1.1.5, 16.2.2.1.2/16.2.2.1.5 and 16.3.2.2/16.3.2.5);

— 10.5.3 for the separate static ultimate strength test in maximum knee flexion on knee joints and associated parts (see also 17.3.4.1);

12.1.1 The manufacturer/submitter shall prepare the test submission document with any associated information and shall provide at least one copy with the batch of test samples of every prosthetic device/structure submitted for test.

12.1.2 The manufacturer/submitter shall, if appropriate, state in the test submission document which of the measurements and recordings of the ankle and knee offsets f_A, f_K, o_A and o_K and/or effective lever arms L_A and L_K, indicated at various stages of the principal structural tests (see 16.2 and 16.3) and the optional separate structural tests on knee locks (see 17.4) shall be carried out.

NOTE Although these data may provide interesting and useful information particularly on the deformation of test samples under load, they are irrelevant to the performance requirements to be satisfied according to the compliance conditions of each of these tests. For this reason, the measurements and recordings referred to will be carried out only if requested by the manufacturer/submitter.

12.1.3 The manufacturer/submitter shall, if appropriate, state in the test submission document which of the information to be recorded in the test log in accordance with this document shall be included in the test report in addition to the information required to be included according to Clause 19.

12.1.4 The manufacturer/submitter shall clearly indicate a name and address for communication purposes. If appropriate, the identity of the original equipment manufacturer shall be provided.

12.1.5 The manufacturer/submitter shall provide a unique and traceable identification for the test submission document which shall also be indelibly marked on the test sample. The manufacturer/submitter shall maintain a record of such identification.

12.1.6 The manufacturer/submitter shall clearly indicate the test laboratory/facility required to conduct the test.

12.1.7 The manufacturer/submitter shall clearly indicate the date of submission or dispatch to the test laboratory/facility.

The following information, attributable to a fully traceable identification for each test sample, shall be included in the test submission document:

a) manufacturer's name and model identification and/or number or other means of identification;

b) type of sample in accordance with 10.2.1, 10.2.2 or 10.2.3;

c) any certification from the manufacturer which states that the test sample has been taken from normal production and which gives details of the method of selection in accordance with 10.1.1;

d) any special assembly instructions for the test sample and/or attachments in accordance with 10.3;

e) if not straightforward, identification of the position of effective centres (6.7.3 and 6.7.6) and/or effective centrelines (6.7.4 and 6.7.5) in accordance with 10.5;

f) identification of the worst-case alignment position in accordance with 10.6;

g) tightening torque values for connecting bolts in accordance with 11.1;

h) record of the supply of any replacement parts provided in accordance with 11.2;

i) record of any end attachments and/or extension pieces and their static alignment in accordance with 10.3, 10.5 (and 11.3).

The manufacturer/submitter shall include in the test submission document

a) a record of any agreement on the identification of the longitudinal axis of the foot in accordance with 6.7.2;

b) information relating to the arrangements for tests on samples of prosthetic structures including ankle-foot devices and foot units, addressed in 9.3;

c) a statement, with justification, of the size of foot providing the worst-case loading, in accordance with 10.1.2.2.

The manufacturer/submitter shall include in the test submission document a specification of the location/position of the knee flexion stop on each type of prosthesis for which the knee unit or knee-shin-assembly can be used according to their intended application, together with an identification of associated parts that are involved in the provision of the knee flexion stop, in accordance with 10.3.4 and 10.3.8.

The information addressed in 12.3.2 to 12.3.7 for each test sample shall be included in the test submission document.

a) The particular test requested (Clauses 9 and 16 or 17) and the test loading condition(s) and test loading levels [Clauses 7 and 8];

b) particular values of dimensions and forces for the conduct of the test (Clause 8);

c) the most adverse assembly and the worst-case alignment of the test sample (10.3.4 and 10.6).

The request to proceed with the test procedure in the second direction of loading on the occurrence of failure in the test procedure in the first direction of loading in accordance with 17.1.3.7, 17.2.3.1.5 and 17.2.4.1.6.

a) If appropriate, request for continuation of the test until failure actually occurs in accordance with 16.2.2.1.6 and/or 17.2.4.1.5/17.2.4.1.11 and recording of the value of the failure load and any further instructions concerning the documentation of test results.

b) Only for principal static ultimate strength tests (16.2.2.1) and separate static ultimate strength tests for ankle-foot devices and foot units (17.2.4.1): the application of an increased rate of loading in accordance with 16.2.2.1.1 and 16.2.2.1.6 and/or 17.2.4.1.1 and 17.2.4.1.5/17.2.4.1.11, and Annex C.

a) The test frequency called for in accordance with 16.3.2.10 and 16.3.2.13 and/or 17.2.5.1.7 and 17.2.5.1.8;

b) Replacement intervals of service items in accordance with 16.3.1.2 and 16.3.2.16, 17.2.5.1.2 a) and 17.2.5.1.9;

c) If appropriate, request for visual examination with specification of magnification in accordance with 16.3.1.4 and 16.3.2.21 and/or 16.2.5.1.2 c) and 17.2.5.1.14. This request shall include instructions concerning the documentation of test results.

d) Only for principal cyclic tests and optional separate cyclic tests for knee locks: the request to carry out the final static test in the manner required to cover the related static proof test in accordance with 16.2.1.1, 16.3.1.3 and 16.3.2.18 and/or 17.4).

e) Only for principal cyclic tests and optional separate cyclic tests for knee locks: if appropriate, specification of a test frequency of less than 3 Hz, to be applied to a substitute test sample in the repetition of test on the occurrence of failure at a test frequency of 3 Hz or higher in accordance with 16.3.2.22.

Identification of the mid-positions of all adjustable components in accordance with 17.1.3.2.

Information related to the arrangements for tests on samples of prosthetic structures including ankle-foot devices and foot units, addressed in 9.3.

The different types of tests listed in Tables 14 and 15 and specified in Clauses 16 and 17 require different types of test equipment.

Each piece of test equipment shall provide sufficient freedom of movement for the test sample to permit and not restrict its deformation under load within the specified range.

Other pieces of equipment are

— end attachments required for specific set-ups of test samples;

— a special jig that may be used on an optional basis to facilitate the setting, adjusting and/or measuring of segment lengths and offsets of test samples;

— any devices used to measure loads and dimensions.

General

For the application of test loading conditions I and II of the principal structural tests, the test sample set-up requires the use of end attachments, consisting of load application levers and non-prosthetic extension pieces.

The end attachments shall not enhance or reduce the stresses due to the specified test loads in the structure under test.

The end attachments shall satisfy the requirements of the proof test of end attachments, specified in 13.2.1.2.

Proof test of end attachments

13.2.1.2.1 The test shall be carried out on end attachments required for the application of test loading conditions I and II of the principal structural tests and Test Ranges (R) specified in 16.2 and 16.3.

The proof test of end attachments is, in principle, also applicable to the end attachments required for the application of the test configuration of the optional separate structural tests for knee locks specified in 17.4 (see 13.6.1). In this case steps 13.2.1.2.3 to 13.2.1.2.11 of the test are to be carried out accordingly.

End attachments which satisfy the stiffness requirements of the proof test of end attachments for proof test forces F_pa = 1,2 F_{su, upper level} of a specific test loading level (see Tables 4, 9) are suitable for all principal static and cyclic tests of this document carried out at this specific test loading level and at all lower levels.

The use of different sets of end attachments, individually designed to the specific requirements of the test loading conditions and Test Ranges (R) of the principal static and cyclic tests of this document (see EXAMPLE) and/or to the specific requirements of the prosthetic devices/structures submitted for test, requires the proof test of end attachments to be applied to each of these sets. In this case each set shall satisfy the stiffness requirements of the proof test of end attachments at values of test force F_pa relating as shown in Table 16 to the highest value of test force F_su, F_sp or F_cmax (see Tables 4, 9) to be applied during the test for which this set has been designed.

EXAMPLE A particular reason for the use of a specific set of (light-weight) end attachments for the cyclic test is the reduction of inertia effects caused by the mass of (heavyweight) universal end attachments suitable for all tests.

It is not necessary to repeat the proof test of end attachments if earlier results for previously tested relevant combinations of end attachments are available and are suitable.

Table 16 — Option for end attachments of specific design<Tbl_-></Tbl_->

13.2.1.2.2 Carry out the proof test of end attachments, consisting of the load application levers and any non-prosthetic extension pieces used, by measuring their stiffness in the manner specified in 13.2.1.2.3 to 13.2.1.2.11.

Assemble any non-prosthetic components used in the test sample for the application of the test loading conditions for the principal structural tests. Set the bottom and the top load application lever in the same plane with the load application points pointing in the same direction.

If the non-prosthetic extension pieces used have means of adjustment, this shall be set to the worst structural condition in the meaning of 10.6, i.e. the adjustment shall be directed away from the load line so as to increase the effective lever arm.

If it is necessary to use additional non-prosthetic components to allow assembly of end attachments, the stiffness of these components shall not be less than the stiffness of the other non-prosthetic components when assembled in the test situation.

Record the details of the assembly of end attachments.

13.2.1.2.3 Within the range of adjustability required for the application of the relevant test loading condition(s) and test loading level(s), set the bottom load application point P_B on the bottom load application lever and the top load application point P_T on the top load application lever (in the same direction) to their maximum distance from a line corresponding to the u-axis of the test sample in the test situation.

If the load application levers are used for the application of several test loading conditions and/or test loading levels, the range of adjustability on each lever shall allow the load application point to be set to the maximum distance required for the application of the test loading condition and/or test loading level with the highest value of combined offset at this point (see 6.8.2 and Table 8).

If, for instance, the load application levers are used for the application of test loading conditions I and II of the principal structural tests at all test loading levels specified, the bottom load application point P_B shall be set to the maximum distance within the range of adjustability required for the application of test loading condition II at test loading level P5 and the top load application point P_T to the maximum distance within the range of adjustability required for the application of test loading condition I at test loading level P3.

Record the details of the adjustment of the bottom and top load application points P_B and P_T.

13.2.1.2.4 Mount the assembly in the test equipment or suitable device.

Record the test loading condition and test loading level to be applied, together with the corresponding values of test forces.

13.2.1.2.5 Apply to the bottom and top load application points of the assembly the settling test force F_set of the relevant test loading condition and test loading level, specified in Table 5.

Maintain this force, F_set, at the prescribed value for (30 ± 3) s and then remove it.

13.2.1.2.6 Apply to the bottom and top load application points of the assembly the stabilizing test force F_stab, specified in Table 5, and maintain it until the measurement specified below is completed.

Measure and record the distance L_BT (see 6.8.4) as L₁ or the displacement δ of the moving load application point from its reference position in the test equipment as δ₁.

13.2.1.2.7 Increase the test force F smoothly at a rate of between 100 N/s and 10 kN/s to the proof test force F_pa of the relevant test loading condition and test loading level, specified in Table 5, and maintain it until the measurement specified below is completed.

Measure and record the distance L_BT as L₂ or the displacement δ of the moving load application point from its reference position in the test equipment as δ₂.

13.2.1.2.8 Decrease the test force F to F_stab and maintain it until the measurement specified below is completed.

Measure and record the distance L_BT as L₃ or the displacement δ of the moving load application point from its reference position in the test equipment as δ₃.

13.2.1.2.9 Calculate and record the deflection, D₁, at F_pa and the permanent deformation, D₂, at F_stab as given in formulae (3) and (4):

D₁ = L₁ − L₂ or D₁ = δ₂ − δ₁ (3)

D₂ = L₁ − L₃ or D₂ = δ₃ − δ₁ (4)

13.2.1.2.10 Do not use the end attachment if the calculated values exceed the following limits:

13.2.1.2.11 Record the results.

A jig can be used to facilitate the setting, adjusting and/or measuring of segment lengths and offsets of test samples for the principal structural tests and the optional separate structural tests on knee locks. It shall be capable of applying the stabilizing test force F_stab while this is carried out.

Test equipment to perform static compression loading – (Compression testing machine or other equipment)

The test equipment shall be capable of producing static test forces at a loading rate of between 100 N/s and 10 kN/s up to the values specified in Table 5 and Table 9 for the relevant test procedure, test loading condition, test loading level and Test Range (R), to be applied in the configurations specified in Tables 6 and 7 and illustrated in Figures A.1 and A.2.

Test equipment to perform cyclic compression loading – (Compression testing machine or other equipment)

13.2.3.2.1 The test equipment shall be capable of producing cyclic test forces up to the values specified in Table 9 for the relevant test loading condition and test loading level, to be applied in the configurations specified in Tables 6 and 7 and illustrated in Figures A.1 and A.2.

13.2.3.2.2 The test equipment shall generate a single pulsating test force F_c(t) as illustrated in Figure 9.

13.2.3.2.3 The waveform of the pulsating test force F_c(t) generated by the test equipment shall be sinusoidal (see Figure 9). If it is certified that a sinusoidal form is not possible, then the waveform of the pulsating test force F_c(t) shall be smooth with no overshoot spikes, characterized by a course corresponding to the description given in 13.2.3.2.5.

13.2.3.2.4 The test force F_c(t) according to 13.2.3.2.2, 13.2.3.2.3 and Figure 9 shall be described/specified by means of any appropriate selection of the following components/parameters:

— minimum test force F_cmin;

— range of the pulsating test force (the cyclic range), F_cr;

— maximum test force, F_cmax;

— mean test force F_cmean;

— amplitude of the pulsating test force (the cyclic amplitude) F_ca.

Key

Figure 9 — Load cycle parameters for the principal cyclic test

13.2.3.2.5 For the purposes of both designation and specification in Table 9 and several requirements in 16.3.2, the test force F_c(t) shall be described as a single pulsating force, oscillating through the cyclic range F_cr with a minimum test force F_cmin to generate a maximum test force F_cmax, where

F_cmax = F_cmin + F_cr. (5)

13.2.3.2.6 For the purposes of setting or programming test machines for generating the pulsating test force F_c(t) as a sine wave, which normally will require the input of the values for the mean test force F_cmean and the cyclic amplitude F_ca, the test force F_c(t) shall be described by the function

F_c(t) = F_cmean + F_ca sin (ω t) with F_cmean = 0,5 (F_cmin + F_cmax) and F_ca = 0,5 F_cr, (6)

where sin (ω t) describes a sine wave with the frequency f = ω/(2π) Hz.

13.2.3.2.7 The test equipment shall switch off if the pulsating test force F_c(t) exceeds the tolerances specified in 14.3 f) and g), with the exception specified in 13.2.3.2.8.

13.2.3.2.8 If the test equipment control mechanism used to generate the pulsating test force F_c(t) requires a number of cycles to achieve the waveform according to 13.2.3.2.3, during this settling in period the waveform of the test force shall be smooth with no overshoot spikes, and the highest force applied shall not exceed the maximum test force F_cmax by more than 10 %.

NOTE Experience has shown that the repeated loading at values exceeding the maximum test force F_cmax by more than 10 % can cause an early deterioration of the test sample.

13.2.3.2.9 The test equipment shall switch off if, when it is running at the prescribed load with the prescribed waveform, the distance L_BT (6.8.4) between the bottom and top load application points P_B and P_T at F_cmax or the displacement δ of the moving load application point from its reference position in the test equipment at F_cmax changes by more than 5 mm from its value at F_cmax, measured and recorded at the initial or previous occasion of start up (16.3.2.10/16.3.2.12).

Test equipment to perform static torsional loading

The test equipment shall be capable of applying torque in a forward and reverse direction up to the values specified in Table 10 at a loading rate not exceeding 4 N·m/s.

Measuring device

The device shall be capable of measuring the angular positions of identified parts relative to twisting about the axis of torque application.

Test equipment to perform static heel and forefoot loading

13.4.1.1.1 The test equipment shall be capable of producing static test forces at a loading rate of between 100 N/s and 10 kN/s up to the values specified in Table 12 for the relevant test procedure, test loading condition and test loading level, to be applied in the directions of loading determined by the angles α and β specified in Table 11, as illustrated in Figure 7.

13.4.1.1.2 The static test forces shall be transmitted to the heel and forefoot portion by a loading platform (loading platforms), which can be adjusted perpendicular to the direction of loading determined by angle α for heel loading and perpendicular to the direction of loading determined by angle β for forefoot loading.

The loading platform(s) shall incorporate appropriate means that minimize the transmission of transverse forces (see Figure 7).

13.4.1.1.3 The loading platform(s) of the test equipment shall have sufficient length to allow simultaneous heel and forefoot contact on one and the same platform.

13.4.1.1.4 Test equipment with a twin actuator set-up shall allow the arrangement

a) of the heel loading platform so that it supports the forefoot if heel loading deforms the test sample to such an extent that forefoot support is necessary to avoid unrealistic conditions of loading and

b) of the forefoot loading platform so that it supports the heel if forefoot loading deforms the test sample to such an extent that heel support is necessary to avoid unrealistic conditions of loading.

13.4.1.1.5 As a consequence of 13.4.1.1.4, test equipment with a twin actuator set-up shall ensure that

a) during a test in heel loading the forefoot cannot contact the forefoot loading platform and

b) during a test in forefoot loading the heel cannot contact the heel loading platform.

Test equipment to perform cyclic heel and forefoot loading

13.4.1.2.1 The test equipment shall be capable of producing cyclic test forces up to the values specified in Table 12 for the relevant test loading condition and test loading level, to be applied in the directions of loading determined by the angles α and β specified in Table 11, as illustrated in Figure 7.

13.4.1.2.2 The cyclic test forces shall be transmitted to the heel and forefoot portion by a loading platform (loading platforms), which can be adjusted perpendicular to the direction of loading determined by angle α for heel loading and perpendicular to the direction of loading determined by angle β for forefoot loading.

The loading platform(s) shall incorporate appropriate means that minimize the transmission of transverse forces (see Figure 7).

13.4.1.2.3 The test equipment shall generate two pulsating test forces F_1c(t) and F_2c(t) as illustrated in Figure 10.

13.4.1.2.4 The waveform of the pulsating test forces F_1c(t) and F_2c(t) generated by the test equipment shall be sinusoidal [see Figure 10 a), b) and c)]. If it is certified that a sinusoidal form is not possible, then the waveform of the pulsating test forces F_1c(t) and F_2c(t) shall be smooth with no overshoot spikes, characterized by a course corresponding to the description given in 13.4.1.2.6.

13.4.1.2.5 The test forces F_1c(t) and F_2c(t) according to 13.4.1.2.3, 13.4.1.2.4 and Figure 10 a), b) and c) shall be described/specified by means of any appropriate selection of the following components/parameters:

— minimum test forces, F_1cmin, F_2cmin;

— ranges of the pulsating test forces (the cyclic ranges), F_1cr, F_2cr;

— maximum test forces F_1cmax, F_2cmax;

— mean test forces, F_1cmean, F_2cmean;

— amplitudes of the pulsating test forces (the cyclic amplitudes) F_1ca, F_2ca.

13.4.1.2.6 For the purposes of both designation and specification in Table 12 and several requirements in 17.2.5.1, the test forces F_1c(t) and F_2c(t) shall be described as single pulsating forces, oscillating through the cyclic ranges F_1cr and F_2cr with the minimum test forces F_1cmin and F_2cmin to generate the maximum test forces F_1cmax and F_2cmax, where

F_1cmax = F_1cmin + F_1cr (7)

F_2cmax = F_2cmin + F_2cr (8)

13.4.1.2.7 For the purposes of setting or programming test machines for generating the pulsating test forces F_1c(t) and F_2c(t) as sine waves or portions of them, which normally will require the input of the values for the mean test forces F_1cmean and F_2cmean and the cyclic amplitudes F_1ca and F_2ca, the test forces F_1c(t) and F_2c(t) shall be described by the functions:

F_1c(t) = F_1cmean + F_1ca sin (ω t) with F_1cmean = 0,5 (F_1cmin + F_1cmax) and F_1ca = 0,5 F_1cr (9)

F_2c(t) = F_2cmean + F_2ca sin (ω t − nπ) with F_2cmean = 0,5 (F_2cmin + F_2cmax) and F_2ca = 0,5 F_2cr (10)

where sin (ω t) describes a sine wave with the frequency f = ω/(2π) Hz, and (ω t − nπ) indicates that F_2c(t) is generated with a phase shift, which corresponds to a half period of the sine wave for n = 1 [Figures 10 a) and c)] and a full period of the sine wave for n = 2 [Figure 10 b)].

13.4.1.2.8 The test equipment shall switch off if the pulsating test forces F_1c(t) and F_2c(t) exceed the tolerances specified in 14.3 f) and g), with the exception specified in 13.4.1.2.9.

13.4.1.2.9 If the test equipment control mechanism used to generate the pulsating test forces F_1c(t) and F_2c(t) requires a number of cycles to achieve the waveform according to 13.4.1.2.4, during this settling in period the waveform shall be smooth with no overshoot spikes, and the highest force applied to the heel or forefoot portion shall not exceed the maximum test force F_1cmax or F_2cmax by more than 10 %.

NOTE Experience has shown that the repeated loading at values exceeding the maximum test force F_1cmax or F_2cmax by more than 10 % can cause an early deterioration of the test sample.

Key

X time

Y test force

1 heel load

2 forefoot load

NOTE Background information on the different loading profiles illustrated in a) to d) is given in Annex E.

Figure 10 — Load cycle parameters for the separate cyclic test for ankle-foot devices and foot units

For the application of the separate static ultimate strength test in maximum knee flexion for knee joints and associated parts, all test samples shall have extension pieces attached above and below the knee unit, to represent wholly or in part the thigh and shin portion.

The posterior shape of the extension pieces shall be of the smallest dimensions possible in accordance with the manufacturer’s instructions, so that the test sample reaches the highest possible value of knee flexion occurring in a normal prosthesis (see 10.6.4).

The stiffness of the extension pieces shall not be less than the stiffness of the thigh and shin portion of a normal prosthesis which they represent wholly or in part.

The test equipment shall be capable of producing static test forces at a loading rate of between 100 N/s and 10 kN/s up to the value specified in Table 13, to be applied in the configuration specified in Table 13 and illustrated in Figure 8.

For the application of the test loading condition for the optional separate structural tests on knee locks, the test sample set-up requires the use of end attachments, consisting of load application levers and non-prosthetic extension pieces.

The end attachments shall not enhance or reduce the stresses due to the specified test loads in the structure under test.

Details of methods used to measure accuracy shall be recorded.

The test equipment, any jig used for alignment and/or measurement and any devices used to measure loads and dimensions shall be calibrated at least annually and whenever any part is replaced. Records of the calibration shall be maintained.

In order to meet the accuracy of procedure specified in 14.3, the test equipment, any jig used for the setting-up of test samples and any measuring devices should be capable of measuring a) to d) to the accuracy specified:

a) linear dimensions to an accuracy of ±0,2 mm,

b) angular dimensions to an accuracy of ±0,2°,

c) test forces and moments to an accuracy of ±1 % of the highest value required in the test, and

d) the frequency of cyclic tests to an accuracy of ±1 % of the test frequency used.

a) Linear dimensions, except segment lengths, shall be initially set and finally adjusted with a tolerance of ±1 mm.

b) Segment lengths shall be set with a tolerance of ±2 mm.

c) Angular dimensions, except the angular “toe-out” position of prosthetic feet, shall be set with a tolerance of ±1°.

d) The angular “toe-out” position of prosthetic feet shall be set with a tolerance of ±3°.

e) Static test forces and moments shall be applied with a tolerance of ±2 % of the highest value prescribed for the test.

NOTE It has been found suitable and sufficiently accurate to use the weight of a mass of 5 kg to develop the stabilizing test force F_stab in any jig used for the adjustment and/or measurement of offsets at F_stab in the upright position of the test sample.

f) Pulsating test forces F_c(t) shall be applied at the instant of F_cmin with a tolerance of ±25 N and at the instant of F_cmax with a tolerance of ±3 % of the value prescribed for F_cmax.

g) The frequency of cyclic tests shall be controlled with a tolerance of ±10 % of the test frequency used.

h) The distance L_BT between the load application points or the displacement δ of the moving load application point shall be controlled with a tolerance of ±1 mm.

The test methods specified in this document use static and cyclic strength tests which typically produce compound loadings by the application of a single test force.

The static tests relate to the worst loads generated in any activity. The cyclic tests relate to normal walking activities where loads occur regularly with each step.

The static test procedure (e.g. 16.2) consists of a proof test (16.2.1) and an ultimate strength test (16.2.2). This test procedure is carried out to determine the performance of the load-bearing structures under typical severe loading conditions that can occur during use by users as occasional single events.

Shock absorption capacity quantified by the ultimate strength test (16.2.2) is determined by carrying out the following:

a) Apply the test force, and increase it smoothly until the test sample fails, the test force is falling below F_{su lower level} during the test or the test sample shows sufficient deflection to demonstrate shock absorption capacity (see below).

b) Derive the deformation rate line at F_{su lower level} (see Note), i.e. gradient of line (r).

c) Calculate the intersection point of the deformation rate line through F_{su, lower level} at
F_{su, upper level}, i.e. point (i) derived from line (r).

d) Calculate the amount of energy theoretically absorbed under the deformation rate line between its intersection with F_{su, lower level} and with F_{su, upper level}, based on the theoretical force value, i.e. the cross hatched area (a).

e) Calculate the real energy absorbed by the specimen under the force-displacement-curve between F_{su, lower level} and the earliest end of the test, point (k), based on the absolute force value, i.e. the cross hatched area (b).

f) The energy integration shall not be continued after the test force is falling below F_{su lower level} during the test, i.e. stop test at point (m) on Figure 12 and Figure 13.

Shock absorption capacity is demonstrated if the real energy absorbed, area (b), exceeds the theoretically absorbed energy, area (a), see Figure 11.

Shock absorption capacity is not demonstrated if the real energy absorbed, area (b), is less than the theoretically absorbed energy, area (a), see Figure 12 and Figure 13.

NOTE: The method to derive the deformation rate can be for example graphical or numerical. The test lab is responsible to use an appropriate method derive the representative deflection rate (for example considering the signal noise) i.e. a tangent on the load-over-deflection curve in F_{su, lower level}.

Key

X deflection

Y force

i point of intersection

k earliest point of end of test

r deformation rate line

a theoretically absorbed energy

b real absorbed energy

Figure 11 — Force-Deflection curve and related areas of shock absorption capacity

Key

X deflection

Y force

i point of intersection

m latest point of end of test

r deformation rate line

a theoretically absorbed energy

b real absorbed energy

Figure 12 — Force-Deflection curve and related insufficient area of shock absorption capacity

Key

X deflection

Y force

i point of intersection

m latest point of end of test

r deformation rate line

Figure 13 — Force-Deflection curve of shock absorption capacity test, test is stopped before point of intersection is reached

The cyclic test procedure (see 16.3) consists of repeated applications of a prescribed load to a test sample with loading conditions typical of normal walking, followed by a final static test (see 16.3.1.3) for which the loading and unloading procedures of the relevant static proof test (see 16.2.1) apply.

The preparation for loading shall proceed as follows.

a) The test sample shall be assembled to a fixed length using end attachments consisting of extension pieces as required and the load application levers (see 10.2, 10.3 and Table 6).

b) In order to establish the position of the line of application of the test force as described in 7.1.2, the test sample shall be set up in the test equipment with the bottom and top load application levers having a combination of forward/backward and outward/inward offsets (see 10.5 and Table 7). Figure 14 shows the geometry for a left leg and Figure 15 gives all the formulae for the calculation of theoretical offsets.

NOTE 1 The preparation for test loading described in a) and b) applies, in principle, also to the optional separate tests for knee locks (see 17.4).

NOTE 2 For some prosthetic designs it may not be possible to set up a test sample in accordance with these requirements. Special test set-ups may then be used in certain cases (see also 10.2.3).

The loading shall be applied in the two test loading conditions I and II described in 7.1.2 and specified in Tables 7, 8 and 9 and illustrated in Figures A.1 and A.2.

No readjustments shall be made to the load application levers if the deflection of the test sample alters the values of the offsets at knee or ankle under these test loading conditions.

NOTE The second requirement also applies, in principle, to the extension pieces of the separate static ultimate strength test in maximum knee flexion for knee joints and associated parts (see 17.3) and to the load application levers of the optional separate tests for knee locks (see 17.4).

Key

1 load line

Figure 14 — Illustration of test loading principle applied to a knee unit with attachments, aligned to simulate a left-sided test sample (see 16.1.1)

Key

Figure 15 — Method of calculating offsets at any height u = u_x (see 16.1.1)

Test method

16.2.1.1.1 Subject to request in the test submission document [see 12.3.5 d)] or agreement between the manufacturer/submitter and the test laboratory/facility, the principal static proof test may be covered by the final static test to be applied to a test sample which has completed the principal cyclic test without failing (see 16.3.1.3 and 16.3.2.17). This requires the application of the final static test in the manner specified in 16.2.1.1.6 to 16.2.1.1.9.

The setting, adjustment and/or measurement of segment lengths and/or offsets [see 16.2.1.1.2, 16.2.1.1.5 and 16.2.1.1.8 b)] shall be carried out with the test sample mounted either in the test equipment or in a special jig capable of applying the stabilizing force F_stab (see 13.2.2).

NOTE A flowchart for this test is shown in Figure 16.

16.2.1.1.2 Prepare and align a test sample from the batch specified in for this test in accordance with 9.5, Clauses 10 and 11, 12.2.1 and 16.1.1 and Tables 6 and 7.

If a test sample which has completed the principal cyclic test procedure (including the final static test) without failing is used for this test in accordance with 9.5.1, re-align it in accordance with Clauses 10 and 11, 12.2.1 and 16.1.1 and Tables 6 and 7 (see also 16.2.1.1.12). Record the re-use of the test sample.

Record the test loading condition and the test loading level to be applied, together with the corresponding values of offsets and test forces.

At zero load, set (or check and, if necessary, correct) the test sample segment lengths (u_A − u_B, u_K − u_A and u_T − u_K or any other specific combination) (see 10.3.6) in accordance with the values specified in Table 6.

Record the combinations and values of the segment lengths set.

At zero load, initially set (or check and, if necessary, correct) the bottom and top load application levers until the initial values of the ankle and knee offsets (f_A, f_K, o_A and o_K) (see 6.8.1) are in accordance with the values for the relevant test loading condition and test loading level, specified in Table 7.

Record the initial values of offsets set.

If the setting of the segment lengths and offsets at zero load has been carried out with the test sample placed in a special jig, transfer the test sample from the jig to the test equipment before proceeding with 16.2.1.1.3.

Record whether a special jig is used.

16.2.1.1.3 Apply to the test sample the settling test force F_set of the relevant test loading condition and test loading level, specified in Table 9.

Maintain the force, F_set, at the prescribed value for a period not less than 10 s and not more than 30 s and then remove it. Record the elapsed time.

Allow the test sample to rest at zero load for a period of not less than 10 min and not more than 20 min before proceeding with 16.2.1.1.4. Record the time at rest.

16.2.1.1.4 Apply to the test sample and maintain during the adjustments of 16.2.1.1.5 and the measurements and recording of 16.2.1.1.6 the stabilizing test force F_stab, specified in Table 9.

If the adjustments of 16.2.1.1.5 are carried out with the test sample placed in a special jig, apply the stabilizing test force F_stab by the jig upon transfer of the test sample from the test equipment to the jig after having completed 16.2.1.1.3 and then remove F_stab and re-apply it by the test equipment upon transfer of the test sample from the jig to the test equipment before proceeding with 16.2.1.1.6.

Record whether a special jig is used.

16.2.1.1.5 Finally adjust the bottom and top load application levers until the final values of the ankle and knee offsets (f_A, f_K, o_A and o_K) are in accordance with the values for the relevant test loading condition and test loading level, specified in Table 7, at the stabilizing test force, F_stab.

Record the final values of offsets set.

16.2.1.1.6 Carry out the following.

a) Measure and record the distance L_BT (see 6.8.4) as L₄ or the displacement δ of the moving load application point from its reference position in the test equipment as δ₄.

b) If requested by the manufacturer/submitter, measure and record the effective lever arms L_A and L_K (see 6.8.3).

Take into account that the data to be acquired are irrelevant to the performance requirements of 16.2.1.2, although they may provide interesting and useful information in conjunction with the data to be acquired according to 16.2.1.1.8 b) particularly on the deformation of the test sample under load. For this reason, carry out these measurements and recordings only if requested by the manufacturer/submitter, as indicated.

16.2.1.1.7 Increase the test force, F smoothly at a rate of between 100 N/s and 10 kN/s to the proof test force F_sp of the relevant test loading condition and test loading level, specified in Table 9.

Maintain this force, F_sp, at the prescribed value for (30 ± 3) s.

Decrease the test force F to F_stab.

If the test sample sustains the static loading at F_sp for the prescribed time, record this and proceed with 16.2.1.1.8.

If the test sample fails to sustain the static loading at F_sp for the prescribed time, record this together with the highest value of test force reached or the time for which the prescribed value of the proof test force F_sp has been maintained and terminate the test (but see 16.2.1.1.12).

16.2.1.1.8 Maintain (or, if a special jig is used, apply and maintain) the stabilizing test force F_stab until the measurements and records of a) [and b)] specified below are completed.

a) Measure and record the distance L_BT as L₅ or the displacement δ of the moving load application point from its reference position in the test equipment as δ₅. Complete the measurement within 5 min (see NOTE).

b) If requested by the manufacturer/submitter, measure and record the offsets f_A, f_K, o_A and o_K, and/or the effective lever arms L_A and L_K. Complete the measurements within 15 min (see NOTE).

Take into account that the data to be acquired are irrelevant to the performance requirements of 16.2.1.2, although they may provide interesting and useful information in conjunction with the data to be acquired according to 16.2.1.1.6 b) particularly on the deformation of the test sample under load. For this reason, carry out these measurements and recordings only if requested by the manufacturer/submitter, as indicated.

If the measurements of b) are carried out with the test sample placed in a special jig, remove the stabilizing test force F_stab and re-apply it by the jig upon transfer of the test sample from the test equipment to the jig after having completed a).

Note and record the interval of time after decreasing the test force F to F_stab (16.2.1.1.7), at which each of the measurements of a) and b) is taken.

Record whether a special jig is used.

NOTE The time limits are set in order to limit the effect of recovery on the permanent deformation (16.2.1.1.9) and on the ankle and knee offsets and effective lever arms. The different values of time limit specified for the measurements of a) and b) take account of the different time required for the measurement and recording.

16.2.1.1.9 Calculate and record the permanent deformation, D₃, between the bottom and top load application points:

(13)

16.2.1.1.10 Decide and record whether the test sample has passed or failed the test procedure specified in 16.2.1.1.2 to 16.2.1.1.9, checking the results of steps 16.2.1.1.7 and 16.2.1.1.9 against the performance requirements of 16.2.1.2.

16.2.1.1.11 If the test sample fails to satisfy either of the performance requirements of 16.2.1.2, inspect it to detect the nature and, if possible, the location of any damage and record the results.

16.2.1.1.12 If a test sample, which has already completed the principal cyclic test procedure without failing (see 16.2.1.1.2), fails to satisfy either of the performance requirements of 16.2.1.2, repeat the test on a substitute test sample and record the failure and the repetition, including all specific records called for.

Performance requirements

In order to pass the principal static proof test, a test sample shall satisfy the following performance requirements.

a) The test sample shall sustain static loading by the proof test force F_sp at the prescribed value for (30 ± 3) s.

b) The value of permanent deformation D₃ of the test sample shall not exceed

— 5 mm for a total sample length (u_T − u_B)_specified = 650 mm or

— 5 mm multiplied by the ratio [(u_T − u_B)_actual/(u_T − u_B)_specified] for values of total sample length exceeding 650 mm (see Footnote b of Table 6).

If any individual prosthetic component fails to satisfy either of the requirements specified in a) and b), this constitutes a failure only in the prosthetic assembly and alignment simulated in the test sample set-up.

Compliance conditions

In order to claim that the prosthetic device/structure submitted for test according to 9.1 to 9.4 complies with the performance requirements of the principal static proof test of this document according to 16.2.1.2 at a specific test loading level, tests of this type shall be passed (in accordance with 16.2.1.2) in each of the test loading conditions I and II by two test samples from the prescribed batch, the prescribed batch including the substitute test sample allowed by 16.2.1.1.12 (see 9.4 and Table 15).

Compliance with the performance requirements of the principal static proof test can also be claimed, if the final static test (16.3.1.3/16.3.2.17) as part of the principal cyclic test procedure (16.3) is applied in the manner specified in 16.2.1.1.6 to 16.2.1.1.9 (see also 16.3.3 and 16.3.4).

Figure 16 — Flowchart for the principal static proof test, specified in 16.2.1.1

Test method

16.2.2.1.1 The setting and/or adjustment of segment lengths and/or offsets (see 16.2.2.1.2 and 16.2.2.1.5) shall be carried out with the test sample mounted either in the test equipment or in a special jig capable of applying the stabilizing test force F_stab (see 13.2.2).

For test samples of lower limb prostheses with material properties and/or construction features which render them unable to sustain the required ultimate test force at a rate of loading of between 100 N/s and 10 kN/s, specified in 16.2.2.1.6.

NOTE A flowchart for this test is shown in Figure 17.

16.2.2.1.2 Prepare and align a test sample from the batch specified in Table 15 for this test in accordance with 9.5, Clauses 10 and 11, 12.2.1 and 16.1.1 and Tables 6 and 7.

If a test sample which has completed the principal static proof test without failing is used for this test in accordance with 9.5.1, re-align it in accordance with Clauses 10 and 11, 12.2.1 and 16.1.1 and Tables 6 and 7 (see also 16.2.2.1.9). Record the re-use of the test sample.

If a test sample which has completed the principal cyclic test procedure (including the final static test) without failing is used for this test in accordance with 9.5.1, re-align it in accordance with Clauses 10 and 11, 12.2.1 and 16.1.1 and Tables 6 and 7 (see also 16.2.2.1.9). Record the re-use of the test sample.

Record the test loading condition and test loading level to be applied, together with the corresponding values of offsets and test forces.

At zero load, set (or check and, if necessary, correct) the test sample segment lengths (u_A − u_B, u_K − u_A and u_T − u_K or any other specific combination) (see 10.3.6) in accordance with the values specified in Table 6.

Record the combinations and values of the segment lengths set.

At zero load, initially set (or check and, if necessary, correct) the bottom and top load application levers until the initial values of the ankle and knee offsets (f_A, f_K, o_A and o_K) (see 6.8.1) are in accordance with the values for the relevant test loading condition and test loading level, specified in Table 7.

Record the initial values of offsets set.

If the setting of the segment lengths and offsets at zero load has been carried out with the test sample placed in a special jig, transfer the test sample from the jig to the test equipment before proceeding with 16.2.2.1.3.

Record whether a special jig is used.

16.2.2.1.3 Apply to the test sample the settling test force F_set of the relevant test loading condition and test loading level, specified in Table 9.

Maintain this force, F_set, at the prescribed value for a period not less than 10 s and not more than 30 s and then remove it. Record the elapsed time.

Allow the test sample to rest at zero load for a period not less than 10 min and not more than 20 min before proceeding with 16.2.2.1.4. Record the time at rest.

16.2.2.1.4 Apply to the test sample and maintain during the adjustments of 16.2.2.1.5 the stabilizing test force F_stab, specified in Table 9.

If the adjustments of 16.2.2.1.5 are carried out with the test sample placed in a special jig, apply the stabilizing test force F_stab by the jig upon transfer of the test sample from the test equipment to the jig after having completed 16.2.2.1.3 and then remove F_stab and re-apply it by the test equipment upon transfer of the test sample from the jig to the test equipment before proceeding with 16.2.2.1.6.

Record whether a special jig is used.

16.2.2.1.5 Finally adjust the bottom and top load application levers until the final values of the ankle and knee offsets (f_A, f_K, o_A and o_K) are in accordance with the values for the relevant test loading condition and test loading level, specified in Table 7, at the stabilizing test force F_stab.

Record the final values of offsets set.

16.2.2.1.6 Increase the test force F smoothly at a rate of between 100 N/s and 10 kN/s until the test sample fails, or the test force F attains the value of the ultimate test force F_{su, upper level} of the relevant test loading condition and test loading level, specified in Table 9, without failure of the test sample.

Record the highest value of the test force F reached during the test and whether failure has occurred. Make specific reference if the test force F is to be applied at a higher rate of loading.

If expressly requested by the manufacturer/submitter, or if requested in the test submission document [see 12.3.4 a)], continue the principal static ultimate strength test after the test sample has withstood the ultimate test force F_{su, upper level} until failure actually occurs and record the value of the load at failure.

Take into account that in this case the end attachments used need a higher value of stiffness and ensure that the values of their deflection and permanent deformation keep within the limits specified in 11.2.1.2.10 at a higher proof load than is specified in Table 5 for the test loading level to be applied.

16.2.2.1.7 Decide and record whether the test sample has passed or failed the test procedure specified in 16.2.2.1.2 to 16.2.2.1.6, checking the results of step 16.2.2.1.6 against the performance requirements of 16.2.2.2.

16.2.2.1.8 If the test sample fails to satisfy any of the performance requirements of 16.2.2.2, inspect it to detect the nature and, if possible the location of any damage and record the results.

16.2.2.1.9 If a test sample, which has already completed the principal static proof test and/or the principal cyclic test procedure without failing (see 16.2.2.1.2), fails to satisfy either of the performance requirements of 16.2.2.2, repeat the test on a substitute test sample and record the failure and the repetition, including all specific records called for.

Performance requirements

In order to pass the principal static ultimate strength test, a test sample shall satisfy one of the following performance requirements:

a) the test sample shall sustain static loading by the ultimate test force F_su at the value prescribed for F_{su, upper level} without failing or

b) if the mechanical characteristics of the test sample prevent the requirement of a) to be satisfied, the test sample shall demonstrate sufficient shock absorption capacity (see 15.2).

If any individual prosthetic component fails to satisfy either of the requirements specified in a) and b), this constitutes a failure only in the prosthetic assembly and alignment simulated in the test sample set-up.

Compliance conditions

In order to claim that the prosthetic device/structure submitted for test according to 9.1 to 9.4 complies with the performance requirements of the principal static ultimate strength test of this document according to 16.2.2.2 at a specific test loading level, the following shall apply.

If the test force F has been applied at a rate of between 100 N/s and 10k N/s, tests of this type shall be passed in accordance with 16.2.2.2 in each of the test loading conditions I and II by two test samples from the prescribed batch, the prescribed batch including the substitute test sample allowed by 16.2.2.1.9 (see 9.4 and Table 15).

Figure 17 — Flowchart for the principal static ultimate strength test, specified in 16.2.2.1

16.3.1.1 If the test frequency selected is higher than 1 Hz, then the maximum frequency shall be below the level at which dynamic mass effects or specific material characteristics (e.g. creep at increased temperatures or relaxation) begin to affect the maximum load value or the waveform.

16.3.1.2 During the course of the cyclic test, specified parts shall be replaced when the number of cycles has reached a value at which such replacement is indicated in accordance with the manufacturer’s/submitter’s service instructions and/or the test submission document [see 12.3.5 b)]. All such replacements shall be recorded.

16.3.1.3 A test sample that completes the cyclic test without failing shall be subjected to final static loading by the test force F_fin, applied at a rate of between 100 N/s and 10 kN/s and maintained for (30 ± 3) s.

Subject to request in the test submission document [see 12.3.5 d)] or agreement between the manufacturer/submitter and the test laboratory/facility, the final static test may also cover the principal static proof test, if applied without re-alignment of the test sample in the manner specified in 16.2.1.1.6 to 16.2.1.1.9.

16.3.1.4 A test sample that fails and/or a test sample that completes the cyclic test without failing shall, at the request of the manufacturer/submitter, be visually examined at the magnification specified in the test submission document [see 12.3.5 c)], and the presence, location and nature of any fractures and/or cracks be recorded, together with the magnification used.

For an alternative approach of testing, see Annex H.

16.3.2.1 The setting, adjustment and/or measurement of segment lengths and/or offsets [see 16.3.2.2, 16.3.2.5, (16.3.2.16 and 16.3.2.17) shall be carried out with the test sample mounted either in the test equipment or in a special jig capable of applying the stabilizing test force F_stab (see 13.2.2).

NOTE A flowchart for this test is shown in Figures 18 to 20.

16.3.2.2 Prepare and align a test sample from the batch specified in Table 15 for this test in accordance with 9.5, Clauses 10 and 11, 12.2.1 and 16.1.1 and Tables 6 and 7.

Record the test loading condition and the test loading level to be applied, together with the corresponding values of offsets, test forces and prescribed number of cycles.

At zero load, set (or check and, if necessary, correct) the test sample segment lengths (u_A − u_B, u_K − u_A and u_T − u_K or any other specific combination) (see 10.3.6) in accordance with the values specified in Table 6.

Record the combinations and values of the segment lengths set.

At zero load, initially set (or check and, if necessary, correct) the bottom and top load application levers until the initial values of the ankle and knee offsets (f_A, f_K, o_A and o_K) (see 6.8.1) are in accordance with the values for the relevant test loading condition and test loading level, specified in Table 7.

Record the initial values of offsets set.

If the setting of the segment lengths and offsets at zero load has been carried out with the test sample placed in a special jig, transfer the test sample from the jig to the test equipment before proceeding with 16.3.2.3.

Record whether a special jig is used.

16.3.2.3 Apply to the test sample the settling test force F_set of the relevant test loading condition and test loading level specified in Table 9.

Maintain this force, F_set, at the prescribed value for a period not less than 10 s and not more than 30 s and then remove it. Record the elapsed time.

Allow the test sample to rest at zero load for a period not less than 10 min and not more than 20 min before proceeding with 16.3.2.4. Record the time at rest.

16.3.2.4 Apply to the test sample and maintain during the adjustments of 16.3.2.5 and the measurements and recording of 16.3.2.6 the stabilizing test force F_stab, specified in Table 9.

If the adjustments of 16.3.2.5 are carried out with the test sample placed in a special jig, apply the stabilizing test force F_stab by the jig upon transfer of the test sample from the test equipment to the jig after having completed 16.3.2.3 and then remove F_stab and re-apply it by the test equipment upon transfer of the test sample from the jig to the test equipment before proceeding with 16.3.2.6.

Record whether a special jig is used.

16.3.2.5 Finally adjust the bottom and top load application levers until the final values of the ankle and knee offsets (f_A, f_K, o_A and o_K) are in accordance with the values for the relevant test loading condition and test loading level, specified in Table 7, at the stabilizing test force F_stab.

Record the final values of offsets set.

16.3.2.6 Carry out the following.

a) Measure and record the distance L_BT (see 6.8.4) as L₆ or the displacement δ of the moving load application point from its reference position in the test equipment as δ₆.

b) If requested by the manufacturer/submitter, measure and record the effective lever arms L_A and L_K (see 6.8.3).

Take into account that the data to be acquired are irrelevant to the performance requirements of 16.3.3, although they may provide interesting and useful information in conjunction with the data to be acquired according to 16.3.2.8 b), 16.3.2.16 and 16.3.2.17 particularly on the deformation of the test sample under load. For this reason, carry out these measurements and recordings only if requested by the manufacturer/ submitter, as indicated.

16.3.2.7 Apply to the test sample the maximum test force F_cmax of the relevant test loading condition and test loading level, specified in Table 9.

Maintain this force, F_cmax, until step 16.3.2.8 is completed.

16.3.2.8 Carry out the following.

a) Measure and record the distance L_BT as L₇ or the displacement δ of the moving load application point from its reference position in the test equipment as δ₇.

b) If requested by the manufacturer/submitter, measure and record the offsets f_A, f_K, o_A and o_K and/or the effective lever arms L_A and L_K.

Take into account that the data to be acquired are irrelevant to the performance requirements of 16.3.3, although they may provide interesting and useful information in conjunction with the data to be acquired according to 16.3.2.6 b), 16.3.2.16 and 16.3.2.17 particularly on the deformation of the test sample under load. For this reason, carry out these measurements and recordings only if requested by the manufacturer/submitter, as indicated.

16.3.2.9 Decrease the test force F to the minimum test force F_cmin specified in Table 9.

If the test sample sustains the static loading at F_cmax until step 16.3.2.8 is completed, proceed with 16.3.2.10.

If the test sample fails to sustain the static loading at F_cmax until step 16.3.2.8 is completed, record this together with the highest value of test force reached or the time for which the prescribed value of the maximum test force F_cmax has been maintained and terminate the test.

16.3.2.10 Apply to the test sample the pulsating test force F_c(t) in accordance with the requirements of 13.2.3.2 and 16.3.1.1 and the values for the relevant test loading condition and test loading level, specified in Table 7, at the frequency called for in the test submission document [see 12.3.5 a)] for a series of cycles, to allow the test sample and the test equipment to “settle down” (see NOTE 1).

NOTE 1 The number of cycles required for the test to settle down will depend on the nature of the test sample and the test equipment control mechanism.

Take care that during this settling in period the highest force applied to the test sample does not exceed the maximum test force F_cmax by more than 10 % (see 13.2.3.2.8 and NOTE 2).

NOTE 2 Experience has shown that the repeated loading at values exceeding the maximum test force F_cmax by more than 10 % can cause an early deterioration of the test sample.

Do not proceed with 16.3.2.11 until the test sample and the test equipment have settled down, and the pulsating test force F_c(t) has achieved the waveform specified in 13.2.3.2.3 and keeps within the tolerances specified in 14.3 f) and g).

Stop the test equipment and record the frequency called for together with the number of cycles required to settle down and whether the pulsating test force F_c(t) is applied in accordance with 13.2.3.2.3 and 14.3 f) and g).

If the frequency called for cannot be achieved or does not allow the pulsating test force F_c(t) to be applied as specified, repeat the preceding steps of 16.3.2.10 at a different frequency, to be agreed upon between the test laboratory/facility and the manufacturer/submitter.

Record any agreement on a frequency differing from the value called for.

If the pulsating test force F_c(t) cannot be applied at any frequency agreed between the test laboratory/facility and the manufacturer/submitter, record this and terminate the test.

16.3.2.11 Apply to the test sample the maximum test force F_cmax.

Measure and record the initial value of the distance L_BT as L₈ or the displacement δ of the moving load application point from its reference position in the test equipment as δ₈.

16.3.2.12 Decrease the test force F to the minimum test force F_cmin.

16.3.2.13 Apply to the test sample the pulsating test force F_c(t) in accordance with the requirements of 13.2.3.2 and 16.3.1.1 and the values for the relevant test loading condition and test loading level, specified in Table 9, at the frequency called for in the test submission document [see 12.3.5 a)] or at a different frequency agreed between the test laboratory/facility and the manufacturer/submitter (see 16.3.2.10) for the prescribed number of cycles specified in Table 9.

Inspect the waveform of the applied pulsating test force F_c(t). Terminate the test if the waveform does not comply with 13.2.3.2.3.

Record the frequency applied, together with the results of the inspection of the waveform and the decision on the continuation of the test.

Set the test equipment displacement trip to 5 mm below the value of the initial distance L₈ at F_cmax or 5 mm above the value of the initial displacement δ₈ at F_cmax, determined in 16.3.2.11.

16.3.2.14 Record the durations and reasons for all occurrences of switch-off, together with the number of cycles of load applied up to that time.

16.3.2.15 Examine the test sample for damage if the test equipment has switched off due to excessive displacement and proceed as follows.

a) If there is no sign of failure, restart the test from 16.3.2.10 and apply the prescribed number of cycles reduced by the number of cycles completed before the test equipment tripped. Record the restart.

b) If the test sample has failed, record this together with the number of cycles at switch-off and terminate the test (but see 16.3.2.22).

16.3.2.16 During the course of the cyclic test, replace any parts which would be replaced in normal service. Proceed as follows.

Stop the test equipment when the number of cycles of load has reached a value at which the exchange/replacement of these parts is indicated in accordance with the manufacturer's/submitter's service instructions and/or the test submission document [see 12.3.5 b) and 16.3.1.2]. Record the number of cycles at shutdown.

Measure and record the distance L_BT or the displacement δ and, if requested by the manufacturer/submitter [note the additional instructions of 16.3.2.6 b) and 16.3.2.8 b)], the offsets f_A, f_K, o_A and o_K and/or the effective lever arms L_A and L_K with the test force F_cmin applied and subsequently with the test force F_cmax applied.

Exchange/replace the specified parts in accordance with the manufacturer's/submitter's service instructions and/or the test submission document.

Restart the test from 16.3.2.2, 16.3.2.3 or 16.3.2.10, depending on the mechanical properties of these parts and the complexity of the dis- and re-assembling of the test sample necessary for their exchange/replacement.

Record the details of the exchange/replacement and the resulting conditions of the restart, together with the number of the corresponding clause.

16.3.2.17 Continue the test until failure occurs or the prescribed number of cycles specified in Table 9 has been completed.

If failure occurs, record this together with the number of cycles at switch-off of the test equipment and terminate the test (but see 16.3.2.22).

If the prescribed number of cycles has been completed, stop the test equipment and measure and record the distance L_BT or the displacement δ and, if requested by the manufacturer/submitter [note the additional instructions of 16.3.2.6 b) and 16.3.2.8 b)], the offsets f_A, f_K, o_A and o_K and/or the effective lever arms L_A and L_K with the test force F_cmin applied and subsequently with the test force F_cmax applied. Record the number of cycles at shutdown.

16.3.2.18 Subject a test sample that completes the cyclic test without failing to the final static test force F_fin of the relevant test loading condition and test loading level, specified in Table 9, applied at a rate of between 100 N/s and 10 kN/s and maintained for (30 ± 3) s (see 16.3.1.3) and record the results.

If the test sample fails to sustain the final static loading at F_fin for the prescribed time, record this together with the highest value of test force reached or the time for which the prescribed value of the final static test force F_fin has been maintained.

If the final static test is intended also to cover the principal static proof test specified in 16.2.1.1.1 (see 16.3.1.3), follow the instructions given in 16.2.1.1.6 to 16.2.1.1.9.

16.3.2.19 Decide and record whether the test sample has passed or failed the test procedure specified in 16.3.2.2 to 16.3.2.18, checking the results of steps 16.3.2.9, 16.3.2.15, 16.3.2.17 and 16.3.2.18 against the performance requirements of 16.3.3.

16.3.2.20 If the test sample fails to satisfy any of the performance requirements of 16.3.3, inspect it to detect the nature and, if possible the location, of any damage and record the results.

16.3.2.21 At the request of the manufacturer/submitter, visually examine a test sample that fails and/or a test sample that completes the principal cyclic test and the final static test without failing, in order to detect the presence, location and nature of any fractures and/or cracks (see 16.3.1.4).

Carry out the examination at the magnification specified in the test submission document [see 12.3.5 c)] or decided according to circumstances in agreement with the manufacturer/submitter.

Record the magnification used and the information obtained, taking account of the manufacturer's/submitter's instructions concerning the documentation of test results [see 12.3.5 c)].

16.3.2.22 If a test sample being tested at a frequency of 3 Hz or higher fails to satisfy any of the performance requirements of 16.3.3, repeat the test on a substitute test sample at a frequency less than 3 Hz, specified in the test submission document [see 12.3.5 e)] or agreed between the test laboratory/facility and the manufacturer/submitter. Record the failure and the repetition, including all specific records called for.

16.3.3.1 In order to pass the principal cyclic test procedure, a test sample shall satisfy the following performance requirements.

a) The test sample shall sustain static loading by the maximum test force F_cmax at the prescribed value for the time required for the measurements and records of 16.3.2.8.

b) The test sample shall sustain cyclic loading by the pulsating test force F_c(t) at the prescribed level and range for the prescribed number of cycles.

c) The test sample shall sustain static loading by the final static test force F_fin at the prescribed value for (30 ± 3) s.

16.3.3.2 In order to also pass the principal static proof test specified in 16.2.1.1.1 when being subjected to the final static test applied in the manner specified in 16.2.1.1.6 to 16.2.1.1.9 for the principal static proof test (see 16.3.1.3 and 16.3.2.18) the test sample shall satisfy 16.3.3.1 c) [which is identical to 16.2.1.2 a)], together with the following performance requirement [which is identical to 16.2.1.2 b)].

The value of permanent deformation D₃ of the test sample shall not exceed

— 5 mm for a total sample length (u_T − u_B)_specified = 650 mm or

— 5 mm multiplied by the ratio [(u_T − u_B)_actual/(u_T − u_B)_specified] for values of total sample length exceeding 650 mm (see Footnote b of Table 6).

If the test sample satisfies the performance requirement of 16.3.3.1 c) but fails to satisfy the performance requirement of 16.3.3.2, the principal static proof test shall be carried out as specified in 16.2.1.1.1.

16.3.3.3 If any individual prosthetic component fails to satisfy any of the requirements specified in 16.3.3.1 and 16.3.3.2, this constitutes a failure only in the prosthetic assembly and alignment simulated in the test sample set-up.

16.3.4.1 In order to claim that the prosthetic device/structure submitted for test according to 9.1 to 9.4 complies with the performance requirements of the principal cyclic test of this document according to 16.3.3.1 at a specific test loading level, tests of this type shall be passed in accordance with 16.3.3.1 in each of the test loading conditions I and II by two test samples from the prescribed batch, the prescribed batch including the substitute test sample allowed by 16.3.2.22 (see 9.4 and Table 15).

16.3.4.2 In order to claim that the prosthetic device/structure submitted for test according to 9.1 to 9.4 also satisfies the compliance conditions of the principal static proof test of this document according to 16.2.1.3, 16.3.4.1 shall apply provided that the test samples also comply with the performance requirement according to 16.3.3.2.

Figure 18 — Flowchart for the principal cyclic test, specified in 16.3.2
Continued on Figures 19 and 20

Figure 19 — Flowchart for the principal cyclic test, specified in 16.3.2
Continued from Figure 18 and continued on Figure 20

Figure 20 — Flowchart for the principal cyclic test, specified in 16.3.2
Continued from Figure 19

The requirements of this subclause shall apply to test samples of all prosthetic devices/structures submitted for test (see Tables 14 and 15).

Users can apply twisting loads to their prostheses which exceed the levels of the twisting moments (induced torque) generated by the test loading conditions of the principal structural tests, specified in this document. To ensure the twisting strength of the prosthetic structure and the security of fixations against slippage, a static load in torsion alone is applied.

NOTE A flowchart for this test is shown in Figure 21.

17.1.3.1 Prepare (or check and, if necessary, correct) the assembly of a test sample from the batch specified in Table 15 for this test in accordance with the manufacturer's assembly instructions and 9.5, Clause 10, 11.4, 11.5 and 12.2.1.

Record the values of the tightening torque(s) of bolts of clamped connections specified in the test submission document (see 11.1 and 12.2.1) and of the twisting moments to be applied.

17.1.3.2 Set up the test sample with the knee unit in full extension and with all adjustable components in their mid-positions in accordance with the test submission document (see 12.3.6).

Where this can neither be established from the test submission document nor from examination of the test sample, then use the manufacturer's written alignment recommendations for the prosthesis to establish the mid-positions.

Record the set-up, including the mid-positions adjusted.

17.1.3.3 Mount the test sample in the test equipment with the effective ankle-joint centre (see 6.7.3) and the effective knee-joint centre (see 6.7.6) on the axis of torque application, in order to generate twisting about the u-axis (see 6.2.2).

17.1.3.4 Fix one end of the test sample and apply to the other end the settling twisting moment M_u-set about the u-axis, specified in Table 10, in a selected direction of twisting designated positive.

Maintain this moment, M_u-set, at the prescribed value for a period of not less than 10 s and not more than 30 s and then remove it.

Allow the test sample to rest at zero load for a period of not less than 10 min and not more than 20 min before proceeding with 17.1.3.5.

Record the time for which the settling twisting moment M_u-set has been maintained at the prescribed value and the time for which the test sample has been allowed to rest at zero load.

17.1.3.5 Apply to the test sample in the positive direction of twisting, the stabilizing twisting moment M_u-stab about the u-axis, specified in Table 10, and maintain it until the markings and readings of 17.1.3.6 are completed.

17.1.3.6 Mark the initial relative angular positions at the junctions of all parts.

Measure and record the initial angular positions relevant to twisting about the u-axis of the bottom and top components of the test sample φ_B1 and φ_T1, respectively.

17.1.3.7 Increase the twisting moment M_u about the u-axis in the positive direction of twisting smoothly at a rate not exceeding 4 N.m/s to the maximum twisting moment M_u-max, specified in Table 10.

Maintain this moment, M_u-max, at the prescribed value for (30 ± 3) s.

Decrease the twisting moment M_u to the stabilizing twisting moment M_u-stab.

If the test sample sustains the static loading at M_u-max for the prescribed time, record this and proceed with 17.1.3.8.

If the test sample fails to sustain the static loading at M_u-max for the prescribed time, record this together with the highest value of twisting moment reached or the time for which the prescribed value of the maximum twisting moment M_u-max has been maintained and decide on the continuation of the test procedure in consideration of the statement given below. Record the decision.

The occurrence of failure in the test procedure in one direction of twisting prevents compliance with the performance requirements of this test being claimed for the test sample (see 17.1.5). For this reason the test shall be terminated, unless otherwise stated in the test submission document or agreed between the test laboratory/facility and the manufacturer/submitter (see 12.3.3).

17.1.3.8 Maintain the stabilizing twisting moment M_u-stab until the measurements specified below are completed. Complete the measurements within 10 min in order to limit the effect of recovery on the relative angular movement (see 17.1.3.9).

Measure and record the final angular positions relevant to twisting about the u-axis of the bottom and top components of the test sample φ_B2 and φ_T2, respectively.

Note and record the time taken for measuring.

17.1.3.9 Calculate and record the relative angular movement about the u-axis between the ends of the test sample Δφ₁ as follows:

(14)

If the calculated value of relative angular movement Δφ₁ exceeds 3°, decide on the continuation of the test procedure in consideration of the statement given in the last paragraph of 15.1.3.7 and record the decision.

17.1.3.10 Check the results of steps 17.1.3.7 and 17.1.3.9 against the performance requirements of 17.1.4 and record the findings.

If the test sample has passed the test procedure in the positive direction of twisting, proceed with 17.1.3.12.

If the test sample has failed this test procedure, decide on the continuation of the test procedure in consideration of the statement given in the last paragraph of 17.1.3.7 and record the decision.

17.1.3.11 If the test sample fails to satisfy either of the performance requirements of 17.1.4, inspect it to detect any slippage of the clamped connections and/or the nature and, if possible, the location of any damage and record the results.

If appropriate, use the markings of the initial angular positions at the junctions of all parts measured in 17.1.3.6 to establish where and what amount of slippage has occurred.

Record the results of the inspection of the test sample.

17.1.3.12 Carry out the test procedure specified in 17.1.3.4 to 17.1.3.9 in the negative direction of twisting.

Designate the angles for this direction of twisting as follows:

a) the initial angular positions (17.1.3.6) as φ_B3 and φ_T3;

b) the final angular positions (17.1.3.8) as φ_B4 and φ_T4;

c) the relative angular movement (17.1.3.9) as Δφ₂, to be calculated as

(15)

Record the application of the test procedure in the negative direction of twisting, together with all specific records called for.

17.1.3.13 Check the results of steps 17.1.3.7 and 17.1.3.9 of the test procedure in the negative direction of twisting against the performance requirements of 17.1.4 and record the findings.

17.1.3.14 If the test sample fails to satisfy either of the performance requirements of 17.1.4 in the test procedure in the negative direction of twisting, inspect it to detect any slippage of the clamped connections and/or the nature and, if possible, the location of any damage and record the results.

If appropriate, use the markings of the initial angular positions at the junctions of all parts measured in 17.1.3.6/17.1.3.12 a) to establish where and what amount of slippage has occurred.

Record the results of the inspection of the test sample.

17.1.3.15 Decide and record whether or not the test sample has passed the test procedure specified in 17.1.3.4 to 17.1.3.9 in both directions of twisting, taking account of the findings of 17.1.3.10 and 17.1.3.13.

In order to pass the separate static test in torsion, a test sample shall satisfy the following performance requirements:

a) the test sample shall sustain static loading in each of the two directions of twisting by the maximum twisting moment M_u-max at the prescribed value of for (30 ± 3) s;

b) the values of relative angular movement Δφ₁ and Δφ₂ between the ends of the test sample occurring in the two directions of twisting shall not exceed 3°.

If any individual prosthetic component fails to satisfy either of the requirements specified in a) and b), this constitutes a failure only in the prosthetic assembly and alignment simulated in the test sample set-up.

In order to claim that the prosthetic device/structure submitted for test according to 9.1 to 9.4 complies with the performance requirements of the separate static test in torsion according to 17.1.4, tests of this type, each successively applying the two directions of twisting to the same test sample, shall be passed (in accordance with 17.1.4) by two test samples from the prescribed batch (see 9.4 and Table 15).

Figure 21 — Flowchart for the separate static test in torsion, specified in 17.1.3

The tests specified in this subclause relate to ankle-foot devices and foot units and their connections to the remainder of the prosthesis. Any report relating to these tests should apply only to the specific ankle-foot device or foot unit in association with the specific connections submitted.

NOTE New static and cyclic tests on ankle-foot devices and foot units are specified in ISO 22675:2024. For further details see last paragraph of Introduction.

Although ankle-foot devices and foot units, representing a part of a test sample or a single component according to 10.2.1, 10.2.2 or 10.2.3, can be subjected to the principal structural tests of Clause 16 in the test configurations of Clause 6 and in the test loading conditions and at the test loading levels of Clause 7, this subclause specifies special structural static and cyclic tests for ankle-foot devices and foot units in which the heel and forefoot are loaded successively or alternately.

To comply with the requirements of this document, a batch of test samples of ankle-foot devices or foot units shall satisfy the performance requirements stated in 17.2.3.2, 17.2.4.2 and 17.2.5.2.

Test method

17.2.3.1.1 The separate static proof test for ankle-foot devices and foot units shall be conducted as described in 17.2.3.1.2 to 17.2.3.1.10, initially applying the test force F₁ on the heel and subsequently applying the test force F₂ on the forefoot of the same test sample, or vice versa.

NOTE A flowchart for this test is shown in Figure 22.

17.2.3.1.2 Prepare and align a test sample from the batch specified in Table 15 for this test, in accordance with 9.5, Clauses 10 and 11, 12.2.1 and 12.2.2 and Table 11.

If a test sample which has completed the separate cyclic test procedure for ankle-foot devices and foot units (including the final static test) without failing is used for this test in accordance with 9.5.1, re-align it in accordance with Clauses 10 and 11, 12.2.1 and 12.2.2 and Table 11 (see also 17.2.3.1.11). Record the re-use of the test sample.

Record the test loading level to be applied, together with the corresponding values of the angles α and β and the test forces F₁ and F₂, determining the directions and magnitudes of heel and forefoot loading.

17.2.3.1.3 For the test in heel loading set the angle of the line of application of the test force F₁ to α, specified in Table 11, and adjust the (heel) loading platform perpendicular to it.

Arrange the (heel) loading platform so that it supports the forefoot, if heel loading deforms the test sample to such an extent that forefoot support is necessary to avoid unrealistic conditions of loading.

If the test equipment uses a twin actuator set-up, ensure that the forefoot cannot contact the forefoot loading platform during heel loading.

17.2.3.1.4 Mount the test sample in the test equipment as illustrated in Figure 7.

17.2.3.1.5 Apply to the heel of the test sample the test force F₁ and increase it smoothly at a rate of between 100 N/s and 10 kN/s to the proof test force F_1sp of the relevant test loading level, specified in Table 12.

Maintain this force, F_1sp, at the prescribed value for (30 ± 3) s and then decrease the test force F₁ to zero.

If the test sample sustains the static heel loading at F_1sp for the prescribed time, record this and proceed with 17.2.3.1.7.

If the test sample fails to sustain the static heel loading at F_1sp for the prescribed time, record this together with the highest value of test force reached or the time for which the prescribed value of the proof test force F_1sp has been maintained and decide on the continuation of the test procedure in consideration of the statement given below (but see 17.2.3.1.11). Record the decision.

The occurrence of failure in the test procedure in one direction of loading prevents compliance with the performance requirements of this test being claimed for the test sample (see 17.2.3.3). For this reason the test shall be terminated, unless otherwise stated in the test submission document or agreed between the test laboratory/facility and the manufacturer/submitter (see 12.3.3).

17.2.3.1.6 If the test sample fails to satisfy the performance requirement of 17.2.3.2 in the test procedure of heel loading, inspect it to detect the nature and, if possible, the location of any damage and record the results.

17.2.3.1.7 For the test in forefoot loading set the angle of the line of application of the test force F₂ to β, specified in Table 11, and adjust the (forefoot) loading platform perpendicular to it.

If appropriate, remove the test sample from the test equipment during the setting and arrangement of the loading platform(s) and subsequently remount it.

Arrange the (forefoot) loading platform so that it supports the heel, if forefoot loading deforms the test sample to such an extent that heel support is necessary to avoid unrealistic conditions of loading.

If the test equipment uses a twin actuator set-up, ensure that the heel cannot contact the heel loading platform during forefoot loading.

17.2.3.1.8 Apply to the forefoot of the test sample that has completed the test procedure of heel loading without failing (see 17.2.3.1.5) the test force F₂ and increase it smoothly at a rate of between 100 N/s and 10 kN/s to the proof test force F_2sp of the relevant test loading level, specified in Table 12.

Maintain this force, F_2sp, at the prescribed value for (30 ± 3) s and then decrease the test force F₂ to zero.

If the test sample sustains the static forefoot loading at F_2sp for the prescribed time, record this.

If the test sample fails to sustain the static forefoot loading at F_2sp for the prescribed time, record this together with the highest value of test force reached or the time for which the prescribed value of the proof test force F_2sp has been maintained (but see 17.2.3.1.11).

17.2.3.1.9 If the test sample fails to satisfy the performance requirement of 17.2.3.2 in the test procedure of forefoot loading, inspect it to detect the nature and, if possible, the location of any damage and record the results.

17.2.3.1.10 Decide and record whether or not the test sample has passed the test procedure of heel loading (17.2.3.1.4 and 17.2.3.1.5) and the test procedure of forefoot loading (17.2.3.1.7 and 17.2.3.1.8), checking the results of 17.2.3.1.5 and 17.2.3.1.8 against the performance requirement of 17.2.3.2.

17.2.3.1.11 If a test sample that has already completed, without failing, the separate cyclic test procedure for ankle-foot devices and foot units (see 17.2.3.1.2), fails to satisfy the performance requirement of 17.2.3.2 in heel loading (17.2.3.1.4 and 17.2.3.1.5) or in forefoot loading (17.2.3.1.7 and 17.2.3.1.8), repeat the complete test (17.2.3.1.2 to 17.2.3.1.9) on a substitute test sample and record the failure and the repetition, including all specific records called for.

Performance requirement

In order to pass the separate static proof test for ankle-foot devices and foot units, a test sample shall sustain successive static heel and forefoot loading by the proof test forces F_1sp and F_2sp at the prescribed values and inclinations for (30 ± 3) s each.

Compliance conditions

In order to claim that the prosthetic device/structure submitted for test according to 9.1 to 9.4 complies with the performance requirement of the separate static proof test for ankle-foot devices and foot units of this document according to 17.2.3.2 at a specific test loading level, tests of this type, each successively applying heel loading and forefoot loading to the same test sample, shall be passed (in accordance with 17.2.3.2) by two test samples from the prescribed batch, the prescribed batch including the substitute test sample allowed by 17.2.3.1.11 (see 9.4 and Table 15).

Figure 22 — Flowchart for the separate static proof test for ankle-foot devices and foot units,
specified in 17.2.3.1

Test method

17.2.4.1.1 The separate static ultimate strength tests for ankle-foot devices and foot units shall be conducted as described in 17.2.4.1.2 to 17.2.4.1.14, on different test samples, loading the first on the heel and the second on the forefoot, or vice versa.

A test sample which satisfies the requirements of this test in one direction of loading, may be used for this test in the other direction of loading (but see 17.2.4.1.16).

For test samples of lower limb prostheses with material properties and/or construction features which render them unable to sustain the required ultimate test force at a rate of loading of between 100 N/s and 10 kN/s, specified in 17.2.4.1.5 and 17.2.4.1.11.

The higher rate of loading shall either be specified in the test submission document [see 12.3.4 b)] by the manufacturer/submitter or agreed upon between the manufacturer/submitter and the test laboratory/facility (see also 17.2.4.1.5 and 17.2.4.1.11) and may be applied to the initial test sample or to a substitute test sample, if the initial test sample has failed at a rate of loading of between 100 N/s and 10 kN/s .

NOTE A flowchart for this test is shown in Figure 23.

17.2.4.1.2 Prepare and align a test sample from the batch specified in Table 15 for this test in accordance with 9.5, Clauses 10 and 11, 12.2.1 and 12.2.2 and Table 11.

If a test sample which has completed the separate static proof test for ankle-foot devices and foot units, without failing, is used for this test in accordance with 9.5.1, re-align it in accordance with Clauses 10 and 11, 12.2.1 and 12.2.2 and Table 11 (see also 17.2.4.1.15). Record the re-use of the test sample.

If a test sample which has completed the separate cyclic test procedure for ankle-foot devices and foot units (including the final static test) without failing is used for this test in accordance with 9.5.1, re-align it in accordance with Clauses 10 and 11, 12.2.1 and 12.2.2 and Table 11 (see also 17.2.4.1.15). Record the re-use of the test sample.

Record the test loading level to be applied, together with the corresponding values of the angle α and the test force F₁, determining the direction and magnitude of heel loading.

17.2.4.1.3 For the test in heel loading set the angle of the direction of loading to α, specified in Table 11, and adjust the (heel) loading platform perpendicular to it.

Arrange the (heel) loading platform so that it supports the forefoot, if heel loading by the test force F₁ deforms the test sample to such an extent that forefoot support is necessary to avoid unrealistic conditions of loading.

If the test equipment uses a twin actuator set-up, ensure that the forefoot cannot contact the forefoot loading platform during heel loading.

17.2.4.1.4 Mount the test sample in the test equipment, as illustrated in Figure 7.

17.2.4.1.5 Apply to the heel of the test sample the test force F₁ and increase it smoothly at a rate of between 100 N/s and 10 kN/s until the test sample fails, or the test force F₁ attains the value of the ultimate test force F_{1su, upper level} of the relevant test loading level, specified in Table 12, without failure of the test sample.

Record the highest value of the test force F₁ reached during the test and whether failure has occurred. Make specific reference if the test force F₁ is to be applied at a higher rate of loading.

If expressly requested by the manufacturer/submitter or if requested in the test submission document [12.3.4 a)], continue the static ultimate strength test after the test sample has withstood the ultimate test force F_{1su, upper level} until failure actually occurs and record the value of the load at failure.

17.2.4.1.6 Check the results of step 17.2.4.1.5 against the performance requirements of 17.2.4.2 and record the findings.

If the test sample completes the test procedure of heel loading without failing, proceed with 17.2.4.1.8.

If the test sample fails, decide on the continuation of the test procedure in consideration of the statement given below (but see 17.2.4.1.15). Record the decision.

The occurrence of failure in the test procedure in one direction of loading prevents compliance with the performance requirements of this test being claimed for the test sample (see 17.2.4.3). For this reason the test shall be terminated, unless otherwise stated in the test submission document or agreed upon between the test laboratory/facility and the manufacturer/submitter (see 12.3.3).

17.2.4.1.7 If the test sample fails to satisfy the performance requirements of 17.2.4.2 in the test procedure of heel loading, inspect it to detect the nature and, if possible, the location of any damage and record the results.

17.2.4.1.8 Prepare and align a fresh test sample from the batch specified in Table 15 for this test in accordance with 9.5, Clauses 10 and 11, 12.2.1 and 12.2.2 and Table 11 (but see 17.2.4.1.1/17.2.4.1.16).

If a test sample which has completed the separate static proof test for ankle-foot devices and foot units without failing is used for this test in accordance with 9.5.1, re-align it in accordance with Clauses 10 and 11, 12.2.1 and 12.2.2 and Table 11 (see also 17.2.4.1.15). Record the re-use of the test sample.

If a test sample that has completed the separate cyclic test procedure for ankle-foot devices and foot units (including the final static test) without failing is used for this test in accordance with 9.5.1, re-align it in accordance with Clauses 10 and 11, 12.2.1 and 12.2.2 and Table 11 (see also 17.2.4.1.15). Record the re-use of the test sample.

Record the test loading level to be applied, together with the corresponding values of the angle β and the test force F₂, determining the direction and magnitude of forefoot loading.

17.2.4.1.9 For the test in forefoot loading set the angle of the direction of loading to β, specified in Table 11, and adjust the (forefoot) loading platform perpendicular to it.

Arrange the (forefoot) loading platform so that it supports the heel, if forefoot loading by the test force F₂ deforms the test sample to such an extent that heel support is necessary to avoid unrealistic conditions of loading.

If the test equipment uses a twin actuator set-up, ensure that the forefoot cannot contact the forefoot loading platform during heel loading.

17.2.4.1.10 Mount the test sample in the test equipment, as illustrated in Figure 7.

17.2.4.1.11 Apply to the forefoot of the test sample the test force F₂ and increase it smoothly at a rate of between 100 N/s and 10 kN/s until the test sample fails, or the test force F₂ attains the value of the ultimate test force F_{2su, upper level} of the relevant test loading level, specified in Table 12, without failure of the test sample.

Record the highest value of the test force F₂ reached during the test and whether failure has occurred. Make specific reference if the test force F₂ is applied at a higher rate of loading.

If expressly requested by the manufacturer/submitter or if requested in the test submission document [12.3.4 a)], continue the static ultimate strength test after the test sample has withstood the ultimate test force F_{2su, upper level}, until failure actually occurs and record the value of the load at failure.

17.2.4.1.12 Check the results of step 17.2.4.1.11 against the performance requirements of 17.2.4.2 and record the findings.

17.2.4.1.13 If the test sample fails to satisfy the performance requirements of 17.2.4.2 in the test procedure of forefoot loading, inspect it to detect the nature and, if possible, the location of any damage and record the results.

17.2.4.1.14 Decide and record whether or not the test sample referred to in 17.2.4.1.2 has passed the test procedure of heel loading (17.2.4.1.2 to 17.2.4.1.5) and the test sample referred to in 17.2.4.1.8 has passed the test procedure of forefoot loading (17.2.4.1.8 to 17.2.4.1.11), taking account of the findings of 17.2.4.1.6 and 17.2.4.1.12.

17.2.4.1.15 If a test sample that has already completed, without failing, the separate static proof test and/or the separate cyclic test procedure for ankle-foot devices and foot units (see 17.2.4.1.2), fails to satisfy either of the performance requirements of 17.2.4.2 in heel loading (17.2.4.1.2 to 17.2.4.1.5) or in forefoot loading (17.2.4.1.8 to 17.2.4.1.11), repeat the test on a substitute test sample in the failed direction of loading and record the failure and the repetition, including all specific records called for.

17.2.4.1.16 If a test sample that has already completed, without failing, the separate static ultimate strength test for ankle-foot devices and foot units in one direction of loading (see 17.2.4.1.1 and 17.2.4.1.6), fails this test in the other direction of loading (see 17.2.4.1.12) repeat the test on a substitute test sample in the failed direction of loading and record the failure and the repetition, including all specific records called for.

Performance requirements

In order to pass the separate static ultimate strength test for ankle-foot devices and foot units, a test sample shall satisfy one of the following performance requirements:

a) the test sample shall sustain either static heel loading by the ultimate test force F_1su at the value and inclination prescribed for F_{1su, upper level} or static forefoot loading by the ultimate test force F_2su at the value and inclination prescribed for F_{2su, upper level} without failing or

b) if the mechanical characteristics of the test sample prevent the requirement of a) to be satisfied, the test sample shall for heel loading or forefoot loading demonstrate sufficient shock absorption capacity (see 15.2).

Compliance conditions

In order to claim that the prosthetic device/structure submitted for test according to 9.1 to 9.4 complies with the performance requirements of the separate static ultimate strength test for ankle-foot devices and foot units of this document according to 17.2.4.2 at a specific test loading level, the following shall apply:

The test forces F₁ and F₂ have been applied at a rate of between 100 N/s and 10 kN/s, tests of this type, each separately applying heel loading and forefoot loading to different test samples, shall be passed (in accordance with 17.2.4.2) in each of these directions of loading by two test samples from the prescribed batch, the prescribed batch including the substitute test samples allowed by 17.2.4.1.15 and 17.2.4.1.16 (see 9.4 and Table 15).

Figure 23 — Flowchart for the separate static ultimate strength test for ankle-foot devices and foot units, specified in 17.2.4.1

Test method

17.2.5.1.1 The separate cyclic test for ankle-foot devices and foot units shall be conducted by alternately loading on the heel and the forefoot of the same test sample, as described in 17.2.5.1.3 to 17.2.5.1.12.

NOTE A flowchart for this test is shown in Figures 24 and 25.

17.2.5.1.2 The following general requirements shall apply.

a) During the course of the cyclic test, specified parts shall be replaced when the number of cycles has reached a value at which such replacement is indicated in accordance with the manufacturer's/submitter's service instructions and/or the test submission document [see 12.3.5 b)]. All such replacements shall be recorded.

b) A test sample that completes the cyclic test without failing shall be subjected to final static heel and forefoot loading by the test forces F_1fin and F_2fin, successively applied at a rate of between 100 N/s and 10 kN/s and maintained for (30 ± 3) s for each loading case.

c) A test sample that fails and/or a test sample that completes the cyclic test without failing shall, at the request of the manufacturer/submitter, be visually examined at the magnification specified in the test submission document [see 12.3.5 c)], and the presence, location and nature of any fractures and/or cracks be recorded, together with the magnification used.

17.2.5.1.3 Prepare and align a test sample from the batch specified in Table 15 for this test in accordance with 9.5, Clause 10 and 11, 12.2.1 and 12.2.2 and Table 11.

Record the test loading level to be applied, together with the corresponding values of the angles α and β and the test forces F₁ and F₂, determining the directions and magnitudes of heel and forefoot loading, and the prescribed number of cycles.

17.2.5.1.4 Set the angle of the direction of heel loading to α and the angle of the direction of forefoot loading to β, specified in Table 11, and adjust the heel and forefoot loading platform(s) perpendicular to the directions of loading.

17.2.5.1.5 Mount the test sample in the test equipment as illustrated in Figure 7.

17.2.5.1.6 Apply to the test sample successively the maximum test force F_1cmax to the heel and the maximum test force F_2cmax to the forefoot in accordance with the values for the relevant test loading level, specified in Table 12.

If the test sample sustains the successive static heel and forefoot loading at F_1cmax and F_2cmax, proceed with 17.2.5.1.7.

If the test sample fails to sustain the successive static heel and forefoot loading at F_1cmax and F_2cmax, record this together with the highest value of test force reached in each direction of loading and terminate the test.

17.2.5.1.7 Apply to the test sample alternately the pulsating test force F_1c(t) to the heel and the pulsating test force F_2c(t) to the forefoot in accordance with the requirements of 13.4.1.2 and the values for the relevant test loading level, specified in Table 12, at a frequency of between 0,5 Hz and 3 Hz in accordance with the test submission document [see 12.3.5 a)] for a series of cycles, to allow the test sample and the test equipment to “settle down”.

NOTE 1 The number of cycles required for the test to settle down will depend on the nature of the test sample and the test equipment control mechanism.

Take care that during this settling in period, the highest force applied to the heel and the forefoot of the test sample does not exceed the maximum test force F_1cmax or F_2cmax by more than 10 % (see 13.4.1.2.9).

NOTE 2 Experience has shown that repeated loading at values exceeding the relevant maximum test force by more than 10 % can cause early deterioration of the test sample.

Do not proceed with 17.2.5.1.8 until the test sample and the test equipment have settled down, and the pulsating test forces F_1c(t) and F_2c(t) have achieved the waveform specified in 13.4.1.2.4 and keep within the tolerances specified in 14.3 f) and g).

Record the frequency called for, together with the number of cycles required to settle down and whether the pulsating test forces F_1c(t) and F_2c(t) are applied in accordance with 13.4.1.2.4 and 14.3 f) and g).

If the frequency called for cannot be achieved or does not allow the pulsating test forces F_1c(t) and F_2c(t) to be applied as specified, repeat the preceding steps of 17.2.5.1.7 at a different frequency, preferably between 0,5 Hz and 3 Hz, to be agreed upon between the test laboratory/facility and the manufacturer/submitter.

Record any agreement on a frequency differing from the value called for.

If the pulsating test forces F_1c(t) and/or F_2c(t) cannot be applied at any frequency agreed between the test laboratory/facility and the manufacturer/submitter, record this and terminate the test.

17.2.5.1.8 Apply to the test sample alternately the pulsating test force F_1c(t) to the heel and the pulsating test force F_2c(t) to the forefoot in accordance with the requirements of 13.4.1.2 and the values for the relevant test loading level, specified in Table 12, at a frequency of between 0,5 Hz and 3 Hz in accordance with the test submission document [see 12.3.5 a)] or any agreement on a frequency differing from the value called for therein, preferably between 0,5 Hz and 3 Hz (see 17.2.5.1.7), for the prescribed number of cycles specified in Table 12.

Inspect the waveform of the applied test forces F_1c(t) and F_2c(t). Terminate the test if the waveform does not comply with 13.4.1.2.4.

Record the frequency applied, together with the results of the inspection of the waveform and the decision on the continuation of the test.

17.2.5.1.9 During the course of the cyclic test, replace any parts which would be replaced in normal service. Proceed as follows.

Stop the test equipment when the number of cycles of load has reached a value at which the exchange/replacement of these parts is indicated in accordance with the manufacturer's/submitter's service instructions and/or the test submission document [see 12.3.5 b) and 17.2.5.1.2 a)]. Record the number of cycles at shutdown.

Exchange/replace the specified parts in accordance with the manufacturer's/submitter's service instructions and/or the test submission document.

Restart the test from 17.2.5.1.3 or 17.2.5.1.7, depending on the mechanical properties of these parts and the complexity of the dis- and re-assembling of the test sample necessary for their exchange/replacement.

Record the details of the exchange/replacement and the resulting conditions of the restart, together with the number of the corresponding clause.

17.2.5.1.10 Continue the test until failure occurs or the prescribed number of cycles specified in Table 12 has been reached for both the heel and the forefoot. Record the number of cycles at shutdown and whether failure has occurred.

17.2.5.1.11 Subject a test sample that completes the cyclic test without failing to the final static test force F_1fin in the direction of heel loading determined by the angle α and subsequently to the final static force F_2fin in the direction of forefoot loading determined by the angle β in accordance with the values for the relevant test loading level, specified in Table 12, applied at a rate of between 100 N/s and 10 kN/s. For each loading case maintain the load at the maximum value for (30 ± 3) s and record the results [see 17.2.5.1.2 b)].

If the test sample fails to sustain the successive final static heel loading at F_1fin and forefoot loading at F_2fin for the prescribed time in either of the directions of loading, record this together with the highest value of test force reached in each direction of loading or the time for which the prescribed values of the final static test forces F_1fin and F_2fin have been maintained.

17.2.5.1.12 Decide and record whether the test sample has passed or failed the test procedure specified in 17.2.5.1.2 to 17.2.5.1.11, checking the results of steps 17.2.5.1.6, 17.2.5.1.10 and 17.2.5.1.11 against the performance requirements of 17.2.5.2.

17.2.5.1.13 If the test sample fails to satisfy any of the performance requirements of 17.2.5.2, inspect it to detect the nature and, if possible, the location of any damage and record the results.

17.2.5.1.14 At the request of the manufacturer/submitter, visually examine a test sample that fails and/or a test sample that completes the separate cyclic test for ankle-foot devices and foot units and the final static test without failing, to detect the presence, location and nature of any fractures and/or cracks [see 17.2.5.1.2 c)].

Carry out the examination at the magnification specified in the test submission document [see 12.3.5 c)] or decided according to circumstances in agreement with the manufacturer/submitter.

Record the magnification used and the information obtained, taking account of the manufacturer's/submitter's instructions concerning the documentation of test results [see 12.3.5 c)].

Performance requirements

In order to pass the separate cyclic test for ankle-foot devices and foot units, a test sample shall satisfy the following performance requirements:

a) the test sample shall sustain successive static heel and forefoot loading by the maximum test forces F_1cmax and F_2cmax at the prescribed values and inclinations;

b) the test sample shall sustain alternating cyclic heel and forefoot loading by the pulsating test forces F_1c(t) and F_2c(t) at the prescribed levels and ranges for the prescribed number of cycles;

c) the test sample shall sustain successive static heel and forefoot loading by the final static test forces F_1fin and F_2fin at the prescribed values and inclinations for (30 ± 3) s each.

Compliance conditions

In order to claim that the prosthetic device/structure submitted for test according to 9.1 to 9.4 complies with the performance requirements of the separate cyclic test for ankle-foot devices and foot units of this document according to 17.2.5.2 at a specific test loading level, tests of this type shall be passed (in accordance with 17.2.5.2) by two test samples from the prescribed batch (see 9.4 and Table 15).

Figure 24 — Flowchart for the separate cyclic test for ankle-foot devices and foot units,
specified in 17.2.5.1
Continued on Figure 25

Figure 25 — Flowchart for the separate cyclic test for ankle-foot devices and foot units,
specified in 17.2.5.1 Continued from Figure 24

The requirements of this test shall apply to all assemblies of knee joints and associated parts that normally provide the knee flexion stop (see 17.3.3.1) on a complete prosthesis, comprising

— assemblies of knee units and adjacent components required for their attachment to the proximal and distal part of a prosthesis and/or their alignment within a prosthesis;

— knee-shin assemblies, including adjacent components required for their attachment to the proximal part of a prosthesis and/or their alignment within a prosthesis.

Users can apply high loads to prostheses in full flexion when kneeling or squatting (deep knee bend). A structural test is required, in order to ensure an adequate level of safety during normal use.

17.3.3.1 The decisive criterion for the applicability of the test specified in 17.3.4 to specific test samples is their involvement in the provision of the knee flexion stop.

NOTE 1 The term “knee flexion stop” used here and in the introductory paragraph of 17.3.1 covers any physical boundaries provided by the assemblies stated in 17.3.1, which stop the angular movement of the knee joint in the position of maximum knee flexion of a complete prostheses. It is not limited to specific knee flexion stop buffers included in some knee joint designs.

In consideration of the complexity of this criterion, for the purposes of this document the decision on the applicability of this test is based on the conditions specified in 17.3.3.2 and 17.3.3.3.

NOTE 2 In some prostheses the maximum knee flexion allowed by the assemblies stated in 17.3.1 is reduced by contact on surfaces of other parts, as e.g. cosmetic components, the socket or the heel of the foot. In these cases the test in maximum knee flexion is not applicable.

17.3.3.2 The separate static ultimate strength test in maximum knee flexion specified in 17.3.4 shall be applied to a specific knee unit or knee-shin-assembly only if the knee flexion stop is incorporated in the knee mechanism or provided by the adjacent components listed in 17.3.1.

This shall be determined as prescribed in 17.3.4.1 and 17.3.4.2, also taking account of the information given in the test submission document (see 12.2.3).

17.3.3.3 The test shall not be applied to a specific knee unit or knee-shin-assembly, if the manufacturer/submitter provides a certificate stating that

a) either kneeling or squatting (deep knee bend) is expressly excluded from its intended use within a complete prosthesis, according to the manufacturer’s written instructions supplied with every component of the type or

b) the knee unit or knee-shin-assembly, together with the adjacent components listed in 17.3.1, does not provide the knee flexion stop on a complete prostheses in any application which is in accordance with the manufacturer’s instructions regarding

— the type(s) of prosthesis (knee-disarticulation, transfemoral and/or hip-disarticulation prosthesis);

— the attachment of the assembly to the proximal and distal part of the prosthesis;

— the alignment of the knee joint within the prosthesis.

The reasons for not testing a submitted sample or not continuing the test shall be recorded.

NOTE A flowchart for this test is shown in Figure 26.

17.3.4.1 Prepare and align a test sample from the batch specified in Table 15 for this test in accordance with 9.5, Clauses 10 and 11, 12.2.1 and 12.2.3 and Table 13.

Record the values of the length L_e and the test force F_su to be applied.

Ensure that the posterior contour/shape and extension of the structures representing the thigh and shin portion within the length L_e (including the extension pieces) is of the smallest dimensions possible in accordance with the manufacturer's instructions, so that the test sample reaches the highest possible value of knee flexion occurring in a normal prosthesis, taking account of

— the use of the knee unit or knee-shin assembly in knee disarticulation, transfemoral and/or hip disarticulation prostheses;

— the attachment of these assemblies to the proximal and distal part of the prosthesis and the alignment of the knee joint within the prosthesis;

— the groups of amputees for whom the use of these assemblies within a complete prosthesis is intended.

Record the parameters of the posterior shape of the structures representing the thigh and shin portion within the length L_e.

17.3.4.2 Move the test sample to the position of maximum knee flexion and detect the location/position of the parts of the test sample which stop further flexion.

Record the location/position of the parts providing the knee flexion stop and proceed as follows.

a) If the knee flexion stop is provided by any parts of the knee unit and adjacent attachment/alignment components or by any parts of the knee-shin assembly listed in 17.3.1, proceed with 17.3.4.3.

b) If the knee flexion stop is not provided by any parts listed in 17.3.1, terminate the test and record that the separate static ultimate strength test in maximum knee flexion is not applicable to the specific structure submitted for test in the specific application, attachment and alignment within a complete prosthesis, simulated in the test sample.

Record the decision on the continuation of the test procedure.

17.3.4.3 Mount the test sample in the test equipment as illustrated in Figure 8.

17.3.4.4 Apply to the ends of the extension pieces the test force F, smoothly and at a rate of between 100 N/s and 10 kN/s until the test sample fails, or the test force F attains the value of static test force F_su, specified in Table 13, without failure of the test sample.

Record the highest value of the test force F reached during the test and whether failure has occurred.

17.3.4.5 Decide and record whether the test sample has passed or failed the test procedure specified in 17.3.4.3 and 17.3.4.4, checking the results of step 17.3.4.4 against the performance requirement of 17.3.5.

17.3.4.6 If the test sample fails to sustain the performance requirement of 17.3.5, inspect it to detect the nature and, if possible, the location of any damage and record the results.

In order to pass the separate static ultimate strength test in maximum knee flexion for knee joints and associated parts, a test sample shall sustain static loading by the static test force F_su at the prescribed value.

In order to claim that the prosthetic device/structure submitted for test according to 9.1 to 9.4 complies with the performance requirement of the separate static ultimate strength test in maximum knee flexion for knee joints and associated parts of this document according to 17.3.5, tests of this type shall be passed (in accordance with 17.3.5) by two test samples from the prescribed batch (see 9.4 and Table 15).

Figure 26 — Flowchart for the separate static ultimate strength test in maximum knee flexion for knee joints and associated parts, specified in 17.3.4

The optional requirements of this subclause shall apply to all knee units incorporating mechanisms which lock the knee in the extended position.

Locked knee units are subject to flexion loading during the stance phase of walking, and a failure of the knee lock mechanism during this phase is potentially hazardous. An optional structural test is required in order to ensure an adequate level of safety during normal use. Manufacturer/submitter defines test conditions, test forces and test geometry and the test laboratory/facility tests accordingly. For an example of a test procedure on separate optional test on knee locks, see 17.4 in the previous edition of this document (ISO 10328:2016).

18.1.1 The test laboratory/facility carrying out the tests specified in this document and indicated in the test submission document shall ensure that all records called for in this document are entered in the test laboratory/facility log.

18.1.2 The submitter of test samples and the identification of the test submission document shall be clearly indicated and the date or dates of receipt be recorded.

18.1.3 The identification of the test report or reports (such as serial number) shall be clearly indicated and the dates of preparation and submission be recorded.

According to the instructions of this document, specific records shall be entered in the test laboratory/facility log for:

a) the identification (number) of the test equipment used and the reference (number) of the end attachments, jig and measuring devices (if used);

b) the selection, type, preparation, identification and alignment of test samples;

c) the conduct of specific tests, selected in accordance with this document and the test submission document;

d) any unusual features observed during the test(s).

NOTE Annex D offers a summary of the records to be entered in the test laboratory/facility log, for general information and guidance of test laboratory/facility staff and submitters (see 19.3).

19.1.1 The test laboratory/facility shall prepare a test report for the test(s) conducted and shall provide at least one copy to the submitter of the test sample.

NOTE The test laboratory/facility should maintain another copy of the test report with the test log. This will simplify the reply to possible further inquiries of the manufacturer/submitter.

19.1.2 The test report shall be signed and dated on behalf of the test laboratory/facility by a designated person.

19.1.3 The test laboratory/facility shall clearly indicate a name and address for communication.

19.1.4 The test laboratory/facility shall provide a unique and traceable identification and date for the test report (such as serial number) including identification of each page, and the total number of pages of the report. The test laboratory/facility shall maintain a record of such identification and date.

19.1.5 The submitter of the test sample, the manufacturer, if known, and the test laboratory/facility identification shall be clearly indicated.

19.1.6 The date of receipt of test samples and date(s) of preparation of the test report shall be clearly indicated.

19.2.1 For each type of test conducted (see 9.4), the test report shall specifically refer to this document, the clauses related to the specific type of test performed, and the test loading condition or direction of loading, the test loading level applied, the applied Test Range (R) and which special test set-ups were used. (see 16.2.1.1.2, 16.2.2.1.2 and 16.3.2.2 and/or 17.2.3.1.2, 17.2.4.1.2, 17.2.4.1.8, 17.2.5.1.3 and 17.3.4.1).

19.2.2 The test report shall include any statements (with justification) of why the separate static ultimate strength test in maximum knee flexion on knee joints and associated parts should not be applied to test samples of a specific prosthetic structure including a knee unit or a knee-shin-assembly (see 17.3.3.3).

19.2.3 For each prosthetic device/structure for which an appropriate batch or batches of test samples have been submitted for test, the test report shall state the tests in which compliance with requirements of this document has been demonstrated. The test report shall also state the tests conducted, in which compliance has not been demonstrated.

If one or more test samples of the prosthetic device/structure submitted for test has/have failed a specific type of test, the test report shall include details of the failure.

19.3.1 The test report shall include any additional information, specifically requested in the test submission document (see 12.1.2 and 12.1.3).

19.3.2 Upon request of the submitter, the test laboratory/facility shall copy from the test log to the test report any further records of samples and test results called for. Annex D gives details of the records to be entered in the test laboratory/facility log according to the instructions of this document.

A lower limb prosthetic device/structure

a) for which compliance with the requirements of this document is claimed (see 9.1, 9.2 and 9.3) for a specific test loading level (P) (see 7.2) and a specific test range (R) and

b) which is suitable for lower limb amputees with a body mass not exceeding a specific value of maximum body mass, m, in kg according to the manufacturer's written instructions on the intended use of that device/structure,

shall be classified and designated as shown below.

ISO 10328 - “P”- “R”- “m” kg

The example below illustrates the classification/designation for lower limb prosthetic device/structure that complies with the requirements of this document for loading level 4 (P4) and the Test Range 3 (R3).

ISO 10328 - P4 – R3 - 80 kg

The classification/designation requires the manufacturer to specify, with justification, the conditions of use in his written instructions on the intended use of the prosthetic ankle-foot device or foot unit (see 7.2.4).

Compliance also can be claimed for lower limb prosthetic devices/structures for amputees, whose body mass is not specified by the P-levels, as defined in 9.6. Applying 9.6, the related body mass is the value for the “body mass value right to the mass symbol” on the indicator.

Each lower limb prosthetic device/structure

a) for which compliance with the requirements of this document is claimed (see 9.1, 9.2 and 9.3) for a specific test loading level “P” (see 7.2.3) and a specific Test Range (R) (see 7.2.4)

b) which is suitable for lower limb amputees with a body mass not exceeding a specific value of maximum body mass “m” kg according to the manufacturer's written instructions on the intended use of that device, shall be identified in accordance with the classification/designation specified in 20.1.

The statements on the identifier shall be given independent of any specific information on the intended use of the prosthetic device/structure supplied by the manufacturer with the device/structure. The symbol ISO 7000-1641 and IEC 60417-5665 shall be marked on the identifier layout and shall conform to Figure 27 and Figure 28.

Figure 27 — General concept for the identifier layout

The series of symbols (operating instructions, body weight) shall allow reference to a brief statement on the identifier, that the value “m” stated specifies the body mass limit not to be exceeded and that further important information on the specific conditions of use is given in the manufacturer's written instructions on the intended use of the device.

The layout of the identifier shall conform to Figure 27 and Figure 28.

Figure 28 — Example for the identifier layout

The identifier shall be placed in the instructions for use in the format ISO 10328 - “P” - “R”- “m” kg or ISO 10328 - P4 – R3 - 80 kg or on the device or on the packaging for each unit or on the sales packaging in the format of Figure 27 and Figure 28. If individual packaging of each unit is not practicable, the identifier shall be placed in the information leaflet supplied with one or more devices.

1. 
   (informative)
   
   Description of internal loads and their effects
   1. General

The test loading conditions of the principal (and separate) structural tests specified in the main body of this document are based on internal reference loads, consisting of an axial force (axial compression), bending moments and a twisting moment (induced torque) indicated in Clause A.3.

The reference forces and moments act respectively along and about reference lines.

• 1. Moment reference lines
     1. General

The moment reference lines are those lines about which the moments specified in Clause A.3 act. They are specified as follows using the elements of the geometric system described in Clause 6.

• • 1. Ankle moment reference lines

A.2.2.1 The ankle moment reference line A_f is the line of intersection of the ankle reference plane (A) with the f-u plane.

A.2.2.2 The ankle moment reference line A_o is the line of intersection of the ankle reference plane (A) with the o-u plane.

• • 1. Knee moment reference lines

A.2.3.1 The knee moment reference line K_f is the line of intersection of the knee reference plane (K) with the f-u plane.

A.2.3.2 The knee moment reference line K_o is the line of intersection of the knee reference plane (K) with the o-u plane.

• 1. Internal loads
     1. General

The internal forces and moments are indicated in A.3.2 and A.3.3, together with anatomical descriptions of their effects. Table A.1 contains a list of these together with alternative descriptions for the movements that positive forces, bending and twisting moments tend to cause.

For a left-sided application, the axial force and all moments shall be positive as illustrated in Figures A.1 and A.2.

For a right-sided application, the mirror image applies (see 6.1 and Figures 1, 2 and 3). As a consequence, the moments M_Af, M_Kf and M_u are positive in the opposite direction.

• • 1. Axial force F_u (axial compression)

The axial force F_u is the force component along the u-axis. Positive F_u tends to compress the prosthesis in its longitudinal direction.

• • 1. Moments
       1. Ankle bending moment, M_Ao

The ankle bending moment M_Ao is the moment about the ankle moment reference line A_o. Positive M_Ao tends to cause dorsiflexion at the ankle joint.

• • • 1. Ankle bending moment, M_Af

The ankle bending moment M_Af is the moment about the ankle moment reference line A_f. Positive M_Af tends to cause inversion at the ankle joint.

• • • 1. Knee bending moment, M_Ko

The knee bending moment M_Ko is the moment about the knee moment reference line K_o. Positive M_Ko tends to cause extension at the knee joint.

• • • 1. Knee bending moment, M_Kf

The knee bending moment M_Kf is the moment about the knee moment reference line K_f. Positive M_Kf tends to cause a lateral movement of the knee relative to foot and hip (tends to cause adduction at the knee joint).

• • • 1. Twisting moment (torque), M_u

The twisting moment M_u is the moment about the u-axis. Positive M_u tends to cause internal rotation of the distal end of the leg relative to the proximal end.

Table A.1 — Positive internal forces and moments with descriptions of their effects

Key

Figure A.1 — Test loading condition I
[see 7.1.2 a)]

Key

Figure A.2 — Test loading condition II [see 7.1.2 b)]

1. 
   (informative)
   
   Reference data for the specification of test loading conditions and test loading levels and Test Ranges (R) of principal cyclic tests
   1. Background statement

The test loading levels P5, P4 and P3 according to 7.2 correspond to the test loading levels A100, A80 and A60 according to ISO 10328-1:1996 to 10328-8:1996. Only the designations have been changed to allow reference to them in classification, designation and identification (see Clauses 20 and 21) without the risk of misinterpretation when stated together with values of body mass.

The test loading levels are based on data acquired at the time of development of ISO 10328:1996, measured on lower limb prostheses of the types used at that time and listed according to the body mass of the amputees whose locomotion was measured. The data used comprised information presented at the Philadelphia meeting in 1977 and additional data subsequently contributed by several countries.

The test loading level P5 is based on data from all amputees including a few whose body mass exceeded 100 kg. The test loading levels P6 and P7 are based on locomotion data from amputees whose body mass is less than 125 kg and 150 kg respectively, obtained from simulations and field observations; P8 is extrapolated from these two levels to amputees whose body mass is less than 175 kg. The test loading levels P4 and P3 are based on locomotion data from amputees whose body mass is less than 80 kg and 60 kg, respectively. The method of classing/relating the test loading levels with/to specific ranges of body mass of amputees on whose locomotion data these are based should, however, not obscure the fact that these locomotion data are also determined by the influence of all other factors, on which the loads developed in a prosthesis during use depend (see NOTE 1); of course only within the range that was possible with respect to the lifestyle and activity level of the amputees and the performance of the lower limb prosthetic devices/structures available at the time of data acquisition (see NOTE 2). All of these factors should therefore be taken into account together with the body mass, when specifying the conditions of use of a specific prosthetic device/structure that complies with the requirements of this document for a specific test loading level and Test Range (R) [see 5.2 b)].

NOTE 1 Besides the general physical parameters and locomotion characteristics of the amputee already addressed in 7.2.1, other specific factors on which the loads developed in a prosthesis during use depend are the individual character of use of the prosthesis by the amputee, determined by her/his lifestyle and activity level, the performance of the prosthesis provided by the mechanical characteristics of the components and their prosthetic assembly and alignment, occasional events such as for example tripping or stumbling, and environmental conditions in which the prosthesis will be used.

NOTE 2 The range of influence of these factors may change in course of time, due to changes in the lifestyle and activity level of amputees and improvements in the performance of prosthetic devices/structures.

• 1. Specification of different test loading conditions and test loading levels for principal cyclic tests

The data referred to in Clause B.1 establish the basis from which to specify the parameters and values of the different test loading conditions described in 7.1.2 and specified in Tables 7, 8 and 9 and of the test loading levels described in 7.2 and designated in 7.2.3.

Tables B.1 and B.3 present the values of the test force F and the related values of the ankle and knee bending moments (see NOTE) for test loading conditions I and II and test loading levels P3, P4, P5, P6, P7 and P8 of the principal cyclic tests. Tables B.2 and B.4 present the values of the axial force and the twisting moment (see NOTE) related to the test force F for test loading conditions I and II and test loading levels P3, P4, P5, P6, P7 and P8 of the principal cyclic tests, calculated with the formulae given in B.3.For the values presented in Tables B.1 and B.2 the test force F corresponds to the cyclic range F_cr of the pulsating test force F_c(t).

For the values presented in Tables B.3 and B.4 the test force F corresponds to the maximum test force F_cmax = F_cmin + F_cr.

NOTE For a description of these internal loads see Annex A.

B.4 presents formulae for calculating the ankle and knee offsets (see 6.8.1 and Table 7) which specify the position of the load lines of test loading conditions I and II (see 7.1.2) within the coordinate systems (see 6.1 to 6.3) so that the internal loads described in Annex A and specified in Tables B.1 to B.4 are simultaneously generated by the test force F.

Table B.1 — Values of ankle and knee moments related to test force F = F_cr for different test loading conditions and test loading levels of principal cyclic tests for Test Range 2 and 3 (R2, R3)

Table B.2 — Calculated values of axial force and twisting moment related to test force F = F_cr for different test loading conditions and test loading levels of principal cyclic tests for Test Range 2 and 3 (R2, R3)

Table B.3 — Values of ankle and knee moments related to test force F = F_cmax for different test loading conditions and test loading levels of principal cyclic tests for Test Range 2 and 3 (R2, R3)

Table B.4 — Calculated values of axial force and twisting moment related to test force F = F_cmax for different test loading conditions and test loading levels of principal cyclic tests for Test Range 2 and 3 (R2, R3)

• 1. Calculation of axial force and twisting moment

Formulae for calculating the axial force F_u and the twisting moment M_u from given values of test force F, knee and ankle moments and the distance u_K − u_A are given in Formulae (B.1) and (B.2) respectively.

(B.1)

(B.2)

• 1. Calculation of ankle and knee offset (see 6.8.1)

Formulae for calculating ankle and knee offsets f and o from given values of axial force F and ankle and knee moments M are given below.

Forward ankle offset:

(B.3)

Outward ankle offset:

(B.4)

Forward knee offset:

(B.5)

Outward knee offset:

(B.6)

1. 
   (informative)
   
   Guidance on the application of an alternative static ultimate strength test
   1. Background statement

Due to the characteristics of most non-metallic materials used in lower limb prostheses, the rate of loading of between 100 N/s and 250 N/s, specified in 16.2.2.1.6 for the principal static ultimate strength test and in 17.2.4.1.5/17.2.4.1.11 for the separate static ultimate strength test for ankle-foot devices and foot units, respectively of ISO 10328:2016, may be too low. It is now defined normative to be a value between 100 N/s and 10 kN/s in the related subclauses.

1. 
   (informative)
   
   Summary of the records to be entered in the test laboratory/facility log
   1. Log records required for the test equipment
      1. Specific records of types of test equipment

The specific type of test equipment used, together with a statement of essential features of the system in accordance with 13.1 to 13.6.

• • 1. Specific records of proof test of end attachments

a) The details of the assembly of end attachments, in accordance with 13.2.1.2.2;

b) the details of the adjustment of the bottom and top load application points P_B and P_T, in accordance with 13.2.1.2.3;

c) the test loading condition and test loading level to be applied, together with the corresponding values of test forces, in accordance with 13.2.1.2.4;

d) the values of the distances L₁, L₂ and L₃ between the two load application points or the displacements δ₁, δ₂ and δ₃ of the moving load application point from its reference position in the test equipment, in accordance with 13.2.1.2.6, 13.2.1.2.7 and 13.2.1.2.8;

e) the values of the deflection D.1 and the permanent deformation D.2, in accordance with 13.2.1.2.9;

f) test results in accordance with 13.2.1.2.11.

• • 1. Specific records of accuracy

a) Details of the methods used to measure accuracy and the calibration of the test equipment and any jig and measuring device in accordance with 14.1;

b) the accuracy of equipment, i.e. the accuracy to which the test equipment and any jig and measuring device measures linear and angular dimensions, test forces and moments and the frequency of cyclic tests, in accordance with 14.2;

c) the accuracy of procedure, i.e. the tolerances with which linear and angular dimensions are set and finally adjusted, test forces and moments are applied and the frequency of cyclic tests and the distance L_BT or the displacement δ are controlled, in accordance with 14.3.

• 1. Log records required for all test samples

a) A fully traceable identification for each sample tested and the date of submission – applied on submission. If the sample has no permanent identification mark, the test laboratory/facility shall affix one after the test/tests has/have been completed;

b) a certificate of sampling from the normal production line, in accordance with 10.1.1;

c) the type of sample in accordance with 10.2.1, 10.2.2 or 10.2.3. In special cases refer to the test submission document;

d) a certificate that the effective geometry of a special test set-up for a special leg structure complies with the requirements of Clauses 8, 16 or 17, as appropriate, in accordance with 10.2.3;

e) details of the preparation of a test sample including a socket or socket dummy in accordance with 10.3.3.

f) the most adverse prosthetic assembly possible in accordance with 10.3.4 and the worst-case alignment position in accordance with 10.6, specified in the test submission document [depending on type of test sample – see c)];

g) the combination of segment lengths selected to achieve the fixed total length, specified in Table 6, in accordance with 10.3.6;

h) the type and identification of that part of the remainder of the prosthesis, to which the ankle-foot device or foot unit is connected in accordance with 10.3.7;

i) the form of the specific assembly and any substituted parts in accordance with 10.3.8;

j) the length of the extension pieces in accordance with 10.3.9;

k) the alignment in accordance with the relevant parts of 10.5 and 11.6;

l) the load application levers used in accordance with 11.4. If these are attached by the manufacturer/submitter, a fully documented test certificate shall be supplied by the manufacturer/submitter;

m) the test loading condition and/or loading level with which compliance or non-compliance shall be demonstrated in accordance with 16.2.1.1.2, 16.2.2.1.2, 16.2.2.1.3, 17.1.3.1, 17.2.3.1.2, 17.2.4.1.2/17.2.4.1.8, 17.2.5.1.3, 17.3.4.1.

• 1. Log records required for all tests

a) The particular tests carried out in accordance with the relevant clauses of this document; in special cases reference to the test submission document will be necessary;

b) the particular dimensions set and loads applied during the tests in accordance with the relevant clauses of this document; in special cases reference to the test submission document will be necessary;

c) the date(s) at which the test(s) has/have been carried out;

d) the test results, i.e. the statement that the prosthetic device/structure submitted for test complies with the requirements of this document, or the reason why it does not comply with these requirements.

• 1. Log records required for principal structural tests
     1. Specific records of principal static proof tests

D.4.1.1 For each test sample of the prosthetic device/structure submitted for test, taken from the prescribed batch according to 16.2.1.3, records of

a) the decision that the principal static proof test shall be covered by the final static test [see D.4.3.1 a)] in accordance with 16.2.1.1.1 or the application of the principal static proof test as part of the static ultimate strength test at increased rate of loading in accordance with 16.2.1.1.1, Clause C.1 and C.2.c) [see also D.6.1. b)];

b) the realignment and re-use of a test sample that has completed the principal cyclic test procedure (including the final static test) without failing in accordance with 16.2.1.1.2;

c) the test loading condition and the test loading level to be applied, together with the corresponding values of offsets and test forces, in accordance with 16.2.1.1.2;

d) the combination and the values of the segment lengths (u_x − u_y) and the initial values of the offsets (f_x and o_x) set at zero load in accordance with 16.2.1.1.2;

e) the use of a special jig in accordance with 16.2.1.1.2, 16.2.1.1.4 and 16.2.1.1.8;

f) the time for which the settling test force F_set has been maintained at the prescribed value and the time for which the test sample has been allowed to rest at zero load in accordance with 16.2.1.1.3;

g) the final values of offsets set with the stabilizing test force F_stab applied in accordance with 16.2.1.1.5;

h) the values of the distance L_BT or the displacement δ and, if requested, the effective lever arms L_A and L_K measured with the stabilizing test force F_stab applied in accordance with 16.2.1.1.6 a) and b);

i) the finding whether or not the test sample sustains the loading by the proof test force F_sp and, if it does not, the highest value of test force reached or the time for which the prescribed value of the proof test force F_sp has been maintained in accordance with 16.2.1.1.7;

j) the values of the distance L_BT or the displacement δ and, if requested, the offsets (f_x and o_x) and/or the effective lever arms L_A and L_K measured with the stabilizing test force F_stab applied, together with the interval of time at which each of the measurements of a) and b) is taken in accordance with 16.2.1.1.8 a) and b);

k) the value of the permanent deformation D₃ calculated in accordance with 16.2.1.1.9;

l) the decision on whether the test sample has passed or failed the principal static proof test in accordance with 16.2.1.1.10;

m) upon inspection of the test sample, the nature and, if possible, the location of any damage in accordance with 16.2.1.1.11;

n) the repetition of the test on a substitute test sample upon failure of a test sample that has already passed the principal cyclic test procedure, including all specific records called for [a) to m)], in accordance with 16.2.1.1.12.

D.4.1.2 For the prosthetic device/structure submitted for test, records of the decision on the compliance with the principal static proof test of this document in accordance with 16.2.1.3, resulting in

a) a statement of compliance or

b) a record of the reason or reasons why compliance cannot be claimed.

• • 1. Specific records of principal static ultimate strength tests

D.4.2.1 For each test sample of the prosthetic device/structure submitted for test, taken from the prescribed batch according to 16.2.2.3, records of

a) the application of static ultimate strength test in accordance with 16.2.2.1.1 and 16.2.2.1.6 [see h) below]. For details of application see D.6.1 a);

b) the realignment and re-use of a test sample that has completed the principal static proof test and/or the cyclic test procedure (including the final static test) without failing in accordance with 16.2.2.1.2;

c) the test loading condition and the test loading level to be applied, together with the corresponding values of offsets and test forces, in accordance with 16.2.2.1.2;

d) the combination and the values of the segment lengths (u_x − u_y) and the initial values of the offsets (f_x and o_x) set at zero load in accordance with 16.2.2.1.2;

e) the use of a special jig in accordance with 16.2.2.1.2 and 16.2.2.1.4;

f) the time for which the settling test force F_set has been maintained at the prescribed value and the time for which the test sample has been allowed to rest at zero load in accordance with 16.2.2.1.3;

g) the final values of offsets set with the stabilizing test force F_stab applied in accordance with 16.2.2.1.5;

h) the highest value of test force reached during the test and whether failure has occurred, making specific reference to the application of the test force at a higher rate of loading, if appropriate [see a)], in accordance with 16.2.2.1.6;

i) at the request of the manufacturer/submitter, the results of the continuation of the test until failure actually occurs in accordance with 12.3.4 a) and 16.2.2.1.6;

j) the decision on whether the test sample has passed or failed the principal static ultimate strength test in accordance with 16.2.2.1.7;

k) the results of the principal static proof test specified in 16.2.1.1, to which a test sample has to be subjected after having passed the static ultimate strength test, in accordance with 16.2.2.1.7;

l) upon inspection of the test sample, the nature and, if possible, the location of any damage in accordance with 16.2.2.1.8;

m) the repetition of the test on a substitute test sample upon failure of a test sample which has already passed the principal static proof test and/or the principal cyclic test procedure, including all specific records called for [a) to l)], in accordance with 16.2.2.1.9;

D.4.2.2 For the prosthetic device/structure submitted for test records of the decision on the compliance with the principal static ultimate strength test of this document in accordance with 16.2.2.3, resulting in

a) a statement of compliance or

b) a record of the reason or reasons why compliance cannot be claimed.

• • 1. Specific records of principal cyclic tests

D.4.3.1 For each test sample of the prosthetic device/structure submitted for test, taken from the prescribed batch according to 16.3.4, records of

a) the application of the final static test in the manner required to cover the principal static proof test specified in 16.2.1.1 in accordance with 16.3.1.3 and 16.3.2.18 [see w) below];

b) the test loading condition and the test loading level to be applied, together with the corresponding values of offsets, test forces and prescribed number of cycles, in accordance with 16.3.2.1;

c) the combination and the values of the segment lengths (u_x − u_y) and the initial values of the offsets (f_x and o_x) set at zero load in accordance with 16.3.2.2;

d) the use of a special jig in accordance with 16.3.2.2 and 16.3.2.4, (16.3.2.16 and 16.3.2.17);

e) the time for which the settling test force F_set has been maintained at the prescribed value and the time for which the test sample has been allowed to rest at zero load in accordance with 16.3.2.3;

f) the final values of offsets set with the stabilizing test force F_stab applied in accordance with 16.3.2.5;

g) the values of the distance L_BT or the displacement δ and, if requested, the effective lever arms L_A and L_K measured with the stabilizing test force F_stab applied in accordance with 16.3.2.6 a) and b);

h) the values of the distance L_BT or the displacement δ and, if requested, the offsets (f_x and o_x) and/or the effective lever arms L_A and L_K measured with the maximum test force F_cmax applied in accordance with 16.3.2.8 a) and b);

i) the finding whether or not the test sample sustains the loading by the maximum test force F_cmax and, if it does not, the highest value of test force reached or the time for which the prescribed value of the maximum test force F_cmax has been maintained in accordance with 16.3.2.9;

j) the frequency called for in accordance with 12.3.5 a), together with the number of cycles required to settle down, in accordance with 16.3.2.10;

k) a statement whether the pulsating test force F_c(t) is applied in accordance with 13.2.3.2.3 and 14.3 f) and g), in accordance with 16.3.2.10;

l) the agreement on a frequency differing from the value called for in accordance with 16.3.2.10;

m) the termination of the test, if the pulsating test force F_c(t) cannot be applied at any frequency agreed upon between the test laboratory/facility and the manufacturer/submitter, in accordance with 16.3.2.10;

n) the initial value of the distance L_BT or the displacement δ measured with the maximum test force F_cmax applied in accordance with 16.3.2.11;

o) the frequency applied, i.e. the frequency called for or agreed [see j) and l)], together with the results of the inspection of the waveform and the decision on the continuation of the test in accordance with 16.3.2.13;

p) the durations and reasons for all occurrences of switch-off, together with the number of cycles of load applied up to that time in accordance with 16.3.2.14;

q) the results of the examination of the test sample and the details of the restart of the test in accordance with 16.3.2.15;

r) the values of the distance L_BT or the displacement δ and, if requested, the offsets (f_x and o_x) and/or the effective lever arms L_A and L_K measured with the minimum test force F_cmin applied and subsequently with the maximum test force F_cmax applied in accordance with 16.3.2.16;

s) the details of the exchange/replacement of specified parts, including the number of cycles at shutdown and the conditions of the restart of the test in accordance with 12.3.5 b), 16.3.1.2 and 16.3.2.16;

t) the occurrence of failure, the number of cycles at switch-off of the test equipment and the termination of the test in accordance with 16.3.2.17;

u) the completion of the cyclic test, together with the number of cycles at shutdown of the test equipment and the values of the distance L_BT or the displacement δ and, if requested, the offsets (f_x and o_x) and/or the effective lever arms L_A and L_K measured with the minimum test force F_cmin applied and subsequently with the maximum test force F_cmax applied in accordance with 16.3.2.17;

v) the finding whether or not the test sample that has passed the cyclic test sustains the final static loading by the test force F_fin to be subsequently applied and, if it does not, the highest value of test force reached or the time for which the prescribed value of the final static test force F_fin has been maintained in accordance with 16.3.2.18.

w) the application of the final static test in the manner required to cover the principal static proof test specified in 16.2.1.1 [see a)], together with the test results, in accordance with 16.3.2.18;

x) the decision on whether the test sample has passed or failed the principal cyclic test in accordance with 16.3.2.19;

y) upon inspection of the test sample, the nature and, if possible, the location of any damage in accordance with 16.3.2.20;

z) upon visual examination of the test sample at the request of the manufacturer/submitter, the presence, location and nature of any cracks, together with the magnification used, in accordance with 12.3.5 c), 16.3.1.4 and 16.3.2.21;

aa)   the repetition of the test on a substitute test sample upon failure of a test sample being tested at a frequency of 3 Hz or higher, including all specific records called for [a) to z)], in accordance with 16.3.2.22;

D.4.3.2 For the prosthetic device/structure submitted for test records of the decision on the compliance with the principal cyclic test of this document in accordance with 16.3.4, resulting in

a) a statement of compliance or

b) a record of the reason or reasons why compliance cannot be claimed.

• 1. Log records required for separate structural tests
     1. Records required for separate static tests in torsion

D.5.1.1 For each test sample of the prosthetic device/structure submitted for test, taken from the prescribed batch according to 17.1.5, records of

a) the value(s) of the tightening torque(s) of any joint-clamping bolts in accordance with 17.1.3.1;

b) the values of the twisting moments to be applied in accordance with 17.1.3.1;

c) the set-up of the test sample, including the mid-positions adjusted in accordance with 17.1.3.2;

d) the time for which the settling twisting moment M_u-set has been maintained at the prescribed value and the time for which the test sample has been allowed to rest at zero load in accordance with 17.1.3.4;

e) the values of the initial angular positions relevant to twisting about the u-axis of the bottom and top components of the test sample φ_B1 and φ_T1, respectively, in accordance with 17.1.3.6;

f) the finding whether or not the test sample sustains the loading by the maximum twisting moment M_u-max in the direction of twisting designated positive and, if it does not, the highest value of twisting moment reached or the time for which the prescribed value of the maximum twisting moment M_u-max has been maintained in accordance with 17.1.3.7;

g) the decision on the continuation of the test procedure in accordance with 12.3.3 and 17.1.3.7;

h) the values of the final angular positions relevant to twisting about the u-axis of the bottom and top components of the test sample φ_B2 and φ_T2, respectively, and the time taken for measuring in accordance with 17.1.3.8;

i) the value of the relative angular movement Δφ₁ about the u-axis in accordance with 17.1.3.9;

j) the decision on the continuation of the test procedure in accordance with 12.3.3 and 17.1.3.9;