Appendix I

CERTIFICATION OF IMPACTORS

1. Certification requirements U.K.

1.1. The impactors that are used in the tests detailed in Part II are required to comply with appropriate performance requirements. U.K.

The requirements for the lower legform impactor are specified in Section 2; the upper legform impactor requirements are specified in Section 3 and the adult, child and child/small adult headform impactor requirements are specified in Section 4.

2. Lower legform impactor U.K.

2.1. Static tests U.K.

2.1.1. The lower legform impactor shall meet the requirements specified in point 2.1.2 when tested as specified in point 2.1.4 and the impactor shall meet the requirements specified in point 2.1.3 when tested as specified in point 2.1.5. U.K.

For both tests the impactor shall have the intended orientation about its longitudinal axis, for the correct operation of its knee joint, with a tolerance of ± 2°.

The stabilised temperature of the impactor during certification shall be 20 °C ± 2 °C.

The CAC response values, as defined in ISO 6487:2000, shall be 50° for the knee bending angle and 500 N for the applied force when the impactor is loaded in bending in accordance with point 2.1.4, and 10 mm for the shearing displacement and 10 kN for the applied force when the impactor is loaded in shearing in accordance with point 2.1.5. For both tests low-pass filtering at an appropriate frequency is permitted, to remove higher frequency noise without significantly affecting the measurement of the response of the impactor.

2.1.2. When the impactor is loaded in bending in accordance with point 2.1.4, the applied force/bending angle response shall be within the limits shown in Figure 1. Also, the energy taken to generate 15,0° of bending shall be 100 ± 7 J. U.K.

2.1.3. When the impactor is loaded in shearing in accordance with point 2.1.5, the applied force/shearing displacement response shall be within the limits shown in Figure 2. U.K.

2.1.4. The legform impactor, without foam covering and skin, shall be mounted with the tibia firmly clamped to a fixed horizontal surface and a metal tube connected firmly to the femur, as shown in Figure 3. To avoid friction errors, no support shall be provided to the femur section or the metal tube. The bending moment applied at the centre of the knee joint, due to the weight of the metal tube and other components (excluding the legform itself), shall not exceed 25 Nm. U.K.

A horizontal normal force shall be applied to the metal tube at a distance of 2,0 ± 0,01 m from the centre of the knee joint and the resulting angle of knee deflection shall be recorded. The load shall be increased until the angle of deflection of the knee is in excess of 22°.

The energy is calculated by integrating the force with respect to the bending angle in radians, and multiplying by the lever length of 2,0 ± 0,01 m.

2.1.5. The impactor, without foam covering and skin, shall be mounted with the tibia firmly clamped to a fixed horizontal surface and a metal tube connected firmly to the femur and restrained at 2,0 m from the centre of the knee joint, as shown in Figure 4. U.K.

A horizontal normal force shall be applied to the femur at a distance of 50 mm from the centre of the knee joint and the resulting knee shearing displacement shall be recorded. The load shall be increased until the shearing displacement of the knee is in excess of 8,0 mm or the load is in excess of 6,0 kN.

2.2. Dynamic tests U.K.

2.2.1. The lower legform impactor shall meet the requirements specified in point 2.2.2 when tested as specified in point 2.2.4. U.K.

The stabilised temperature of the impactor during certification shall be 20 °C ± 2 °C.

2.2.2. When the impactor is impacted by a linearly guided certification impactor, as specified in point 2.2.4, the maximum upper tibia acceleration shall be not less than 120 g and not more than 250 g. The maximum bending angle shall be not less than 6,2° and not more than 8,2°. The maximum shearing displacement shall be not less than 3,5 mm and not more than 6,0 mm. U.K.

For all these values the readings used shall be from the initial impact with the certification impactor and not from the arresting phase. Any system used to arrest the impactor or certification impactor shall be so arranged that the arresting phase does not overlap in time with the initial impact. The arresting system shall not cause the transducer outputs to exceed the specified CAC.

2.2.3. The instrumentation response value CFC, as defined in ISO 6487:2000, shall be 180 for all transducers. The CAC response values, as defined in ISO 6487:2000, shall be 50° for the knee bending angle, 10 mm for the shearing displacement and 500 g for the acceleration. This does not require that the impactor itself be able to physically bend and shear to these angles and displacements. U.K.

2.2.4 Test procedure U.K.

2.2.4.1. The impactor, including foam covering and skin, shall be suspended horizontally by three wire ropes of 1,5 ± 0,2 mm diameter and of 2,0 m minimum length, as shown in Figure 5a. It shall be suspended with its longitudinal axis horizontal, with a tolerance of ± 0,5°, and perpendicular to the direction of the certification impactor motion, with a tolerance of ± 2°. The impactor shall have the intended orientation about its longitudinal axis, for the correct operation of its knee joint, with a tolerance of ± 2°. The impactor must meet the requirements of point 3.4.1.1, Chapter II of Part II with the attachment bracket(s) for the wire ropes fitted. U.K.

2.2.4.2. The certification impactor shall have a mass of 9,0 ± 0,05 kg, this mass includes those propulsion and guidance components which are effectively part of the impactor during impact. The dimensions of the face of the certification impactor shall be as specified in Figure 5b. The face of the certification impactor shall be made of aluminium, with an outer surface finish of better than 2,0 micrometers. U.K.

The guidance system shall be fitted with low friction guides, insensitive to off-axis loading, that allow the impactor to move only in the specified direction of impact, when in contact with the vehicle. The guides shall prevent motion in other directions including rotation about any axis.

2.2.4.3. The impactor shall be certified with previously unused foam. U.K.

2.2.4.4. The impactor foam shall not be excessively handled or deformed before, during or after fitting. U.K.

2.2.4.5. The certification impactor shall be propelled horizontally at a velocity of 7,5 ± 0,1 m/s into the stationary impactor as shown in Figure 5a. The certification impactor shall be positioned so that its centreline aligns with a position on the tibia centreline of 50 mm from the centre of the knee, with tolerances of ± 3 mm laterally and ± 3 mm vertically. U.K.

3. Upper legform impactor U.K.

3.1. The upper legform impactor shall meet the requirements specified in point 3.2 when tested as specified in point 3.3. U.K.

The stabilised temperature of the impactor during certification shall be 20 °C ± 2 °C.

3.2. Requirements U.K.

3.2.1. When the impactor is propelled into a stationary cylindrical pendulum the peak force measured in each load transducer shall be not less 1,20 kN and not more than 1,55 kN and the difference between the peak forces measured in the top and bottom load transducers shall not be more than 0,10 kN. Also, the peak bending moment measured by the strain gauges shall not be less than 190 Nm and not more than 250 Nm on the centre position and not less than 160 Nm and not more than 220 Nm for the outer positions. The difference between the upper and lower peak bending moments shall not be more than 20 Nm. U.K.

For all these values the readings used shall be from the initial impact with the pendulum and not from the arresting phase. Any system used to arrest the impactor or pendulum shall be so arranged that the arresting phase does not overlap in time with the initial impact. The arresting system shall not cause the transducer outputs to exceed the specified CAC.

3.2.2. The instrumentation response value CFC, as defined in ISO 6487:2000, shall be 180 for all transducers. The CAC response values, as defined in ISO 6487:2000, shall be 10 kN for the force transducers and 1 000 Nm for the bending moment measurements. U.K.

3.3. Test procedure U.K.

3.3.1. The impactor shall be mounted to the propulsion and guidance system, by a torque limiting joint. The torque limiting joint shall be set so that the longitudinal axis of the front member is perpendicular to the axis of the guidance system, with a tolerance of ± 2°, with the joint friction torque set to a minimum of 650 Nm. The guidance system shall be fitted with low friction guides that allow the impactor to move only in the specified direction of impact, when in contact with the pendulum. U.K.

3.3.2. The impactor mass shall be adjusted to give a mass of 12 ± 0,1 kg, this mass includes those propulsion and guidance components which are effectively part of the impactor during impact. U.K.

3.3.3. The centre of gravity of those parts of the impactor which are effectively forward of the torque limiting joint, including the extra weights fitted, shall lie on the longitudinal centreline of the impactor, with a tolerance of ± 10 mm. U.K.

3.3.4. The impactor shall be certified with previously unused foam. U.K.

3.3.5. The impactor foam shall not be excessively handled or deformed before, during or after fitting. U.K.

3.3.6. The impactor with the front member vertical shall be propelled horizontally at a velocity of 7,1 ± 0,1 m/s into the stationary pendulum as shown in Figure 6. U.K.

3.3.7. The pendulum tube shall have a mass of 3 ± 0,03 kg, an outside diameter of and a wall thickness of 3 ± 0,15 mm. Total pendulum tube length shall be 275 ± 25 mm. The pendulum tube shall be made from cold finished seamless steel (metal surface plating is permissible for protection from corrosion), with an outer surface finish of better than 2,0 micrometers. It shall be suspended on two wire ropes of 1,5 ± 0,2 mm diameter and of 2,0 m minimum length. The surface of the pendulum shall be clean and dry. The pendulum tube shall be positioned so that the longitudinal axis of the cylinder is perpendicular to the front member (i.e. level), with a tolerance of ± 2°, and to the direction of impactor motion, with a tolerance of ± 2°, and with the centre of the pendulum tube aligned with the centre of the impactor front member, with tolerances of ± 5 mm laterally and ± 5 mm vertically. U.K.

4. Headform impactors U.K.

4.1. The child, child/small adult and the adult headform impactors shall meet the requirements specified in point 4.2 when tested as specified in point 4.3. U.K.

The stabilised temperature of the impactors during certification shall be 20 °C ± 2 °C.

4.2. Requirements U.K.

4.2.1. When the child headform impactor is impacted by a linearly guided certification impactor, as specified in point 4.3, the peak resultant acceleration measured by one triaxial (or three uniaxial) accelerometer in the headform shall be not less than 405 g and not more than 495 g. The resultant acceleration time curve shall be uni-modal. U.K.

4.2.2. When the child/small adult headform impactor is impacted by a linearly guided certification impactor, as specified in point 4.3, the peak resultant acceleration measured by one triaxial (or three uniaxial) accelerometer in the headform shall be not less than 290 g and not more than 350 g. The resultant acceleration time curve shall be uni-modal. U.K.

4.2.3. When the adult headform impactor is impacted by a linearly guided certification impactor, as specified in point 4.3, the peak resultant acceleration measured by one triaxial (or three uniaxial) accelerometer in the headform shall be not less than 337,5 g and not more than 412,5 g. The resultant acceleration time curve shall be uni-modal. U.K.

4.2.4. The instrumentation response value CFC, as defined in ISO 6487:2000, shall be 1 000. The CAC response value, as defined in ISO 6487:2000, shall be 1 000 g for the acceleration. U.K.

4.3. Test procedure U.K.

4.3.1. The headform impactors shall be suspended as shown in Figure 7. The headform impactors shall be suspended with the rear face at an angle between 25° and 90° with the horizontal, as shown in Figure 7. U.K.

4.3.2. The certification impactor shall have a mass of 1,0 ± 0,01 kg. This mass includes those propulsion and guidance components which are effectively part of the impactor during impact. The linear guidance system shall be fitted with low friction guides which do not contain any rotating parts. The diameter of the flat impactor face shall be 70 ± 1 mm, while the edge shall be rounded by a 5 ± 0,5 mm radius. The face of the certification impactor shall be made of aluminium, with an outer surface finish of better than 2,0 micrometers. U.K.

4.3.3. The certification impactor shall be propelled horizontally at a velocity of 7,0 ± 0,1 m/s into the stationary child and child/small adult headform impactors and at a velocity of 10,0 ± 0,1 m/s into the stationary adult headform impactor. The certification impactor shall be positioned so that the centre of gravity of the headform impactor is located on the centre line of the certification impactor, with tolerances of ± 5 mm laterally and ± 5 mm vertically. U.K.

4.3.4. The test shall be performed on three different impact locations on each headform impactor. Previously used and/or damaged skins shall be tested in those specific areas. U.K.

Table 1: Summary of response requirements for headform impactors

Impactor and mass	Certification velocity [m/s]	Lower Boundary [g]	Upper, Boundary [g]
Child 2,5 kg	7	405	495
Child/small adult 3,5 kg	7	290	350
Adult 4,8 kg	10	337,5	412,5

Figure 1

Force versus angle requirement in static lower legform impactor bending certification test

Figure 2

Force versus displacement requirement in static lower legform impactor shearing certification test

Figure 3

Top view of test set-up for static lower legform impactor bending certification test

Figure 4

Top view of test set-up for static lower legform impactor shearing certification test

Figure 5a

Test set-up for dynamic lower legform impactor certification test (side view top diagram, view from above bottom diagram)

Figure 5b

Details of dynamic lower legform certification impactor face

Notes: U.K.

1. Saddle may be made as a complete diameter and cut as shown to make two components. U.K.

2. The shaded areas may be removed to give the alternative form shown. U.K.

3. Tolerance on all dimensions is ± 1,0 mm. U.K.

Material: aluminium alloy

Figure 6

Test set-up for dynamic upper legform impactor certification test

Figure 7

Test set-up for dynamic headform impactor certification test