§ 572.176 Knees and knee impact test procedure.

(a) The knee assembly for the purpose of this test is the part of the leg assembly shown in drawing 420-5000 (incorporated by reference, see § 572.170). (b) When the knee assembly, consisting of lower upper leg assembly (420-5200), femur load transducer (SA572-S10, included in drawing 420-0000) or its structural replacement (420-5121), lower leg assembly (420-5300), ankle assembly (420-5400), and foot molded assembly (420-5500) (all incorporated by reference, see § 572.170) is tested according to the test procedure in subsection (c) of this section: (1) The peak resistance force as measured with the test probe-mounted accelerometer must not be less than 2.6 kN (585 lbf) and not more than 3.2 kN (719 lbf). (2) The force shall be calculated by the product of the impactor mass and its deceleration. (c) Test Procedure. The test procedure for the knee assembly is as follows: (1) Soak the knee assembly in a controlled environment at any temperature between 20.6 and 22.2 °C (69 and 72 °F) and a relative humidity between 10 and 70 percent for at least four hours prior to a test. (2) Mount the test material and secure it to a rigid test fixture as shown in Figure T6. No part of the foot or tibia may contact any exterior surface. (3) Align the test probe so that throughout its stroke and at contact with the knee it is within 2 degrees of horizontal and collinear with the longitudinal centerline of the femur. (4) Guide the pendulum so that there is no significant lateral, vertical, or rotational movement at the time of initial contact between the impactor and the knee. (5) The test probe velocity at the time of contact shall be 2.1 ±0.03 m/s (6.9 ±0.1 ft/s). (6) No suspension hardware, suspension cables, or any other attachments to the probe, including the velocity vane, shall make contact with the dummy during the test.