572.187—Lumbar spine.
(a)
The lumbar spine assembly consists of parts shown in drawing 175-5500. For purposes of this test, the lumbar spine is mounted within the headform assembly 175-9000 as shown in Figure U1 in appendix A to this subpart. When subjected to tests procedures specified in paragraph (b) of this section, the lumbar spine-headform assembly shall meet performance requirements specified in paragraph (c) of this section.
(b) Test procedure.
(1)
Soak the lumbar spine-headform assembly in a test environment as specified in § 572.189(n) ;
(2)
Attach the lumbar spine-headform assembly to the Part 572 pendulum test fixture per procedure in § 572.183(b)(2) and as shown in Figure U2-A in appendix A to this subpart. Torque the lumbar hex nut (p/n 9000057) on to the lumbar cable assembly (175-5506) to 50 ± 5 in-lb;
(3)
Release the pendulum from a height sufficient to allow it to fall freely to achieve an impact velocity of 6.05 ±0.1 m/s measured at the center of the pendulum accelerometer (Figure 22) at the time the pendulum makes contact with its decelerating mechanism. The velocity-time history of the pendulum falls inside the corridor determined by the upper and lower boundaries specified in Table 1 to paragraph (b) of this section;
(4)
Allow the lumbar spine to flex without the lumbar spine or the headform making contact with any object;
| Upper boundary | Lower boundary | ||
|---|---|---|---|
| Time(ms) | Velocity(m/s) | Time(ms) | Velocity(m/s) |
| 1.0 | 0.00 | 0.0 | −0.05 |
| 3.7 | −0.24 | 2.7 | −0.425 |
| 27.0 | −5.80 | 24.5 | −6.50 |
| 30.0 | −6.50 | ||
(c) Performance criteria.
(1)
The pendulum deceleration pulse is to be characterized in terms of decrease in velocity as determined by integrating the filtered pendulum acceleration response from time-zero.
(2)
The maximum rotation in the lateral direction of the reference plane of the headform (175-9000) as shown in Figure U2-B in appendix A to this subpart, shall be 45 to 55 degrees with respect to the longitudinal axis of the pendulum occurring between 39 and 53 ms from time zero. Rotation of the headform-neck assembly shall be measured with potentiometers specified in § 572.189(c), installed as shown in drawing 175-9000, and calculated per procedure specified in Figure U2-B in appendix A to this subpart.
(3)
The decaying headform rotation vs. time curve shall cross the zero angle with respect to its initial position at impact relative to the pendulum centerline between 37 ms to 57 ms after the time the peak translation-rotation value is reached.
[71 FR 75331, Dec. 14, 2006, as amended at 73 FR 33921, June 16, 2008]