§ 572.183 Neck assembly.

(a) The neck assembly consists of parts shown in drawing 175-2000. For purposes of this test, the neck 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 neck-headform assembly shall meet performance requirements specified in paragraph (c) of this section. (b) Test procedure. (1) Soak the neck-headform assembly in a test environment as specified in § 572.189(n); (2) Attach the neck-headform assembly to the part 572 subpart E pendulum test fixture as shown in Figure U2-A in appendix A to this subpart, so that the midsagittal plane of the neck-headform assembly is vertical and perpendicular to the plane of motion of the pendulum longitudinal centerline shown in Figure U2-A. Torque the half-spherical screws (175-2004) located at either end of the neck assembly to 88 ±5 in-lbs using the neck compression tool (175-9500) or equivalent; (3) Release the pendulum from a height sufficient to allow it to fall freely to achieve an impact velocity of 3.4±0.1 m/s measured at the center of the pendulum accelerometer (Figure 22 as set forth in 49 CFR 572.33) at the time the pendulum makes contact with the 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 (a) of this section. (4) Allow the neck to flex without the neck-headform assembly making contact with any object; (5) Time zero is defined in § 572.189(j). Table 1 to Paragraph (a)—ES-2re Neck Certification Pendulum Velocity Corridor (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 49 to 59 degrees with respect to the longitudinal axis of the pendulum occurring between 54 and 66 ms from time zero. Rotation of the headform-neck assembly and the neck angle with respect to the pendulum 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 time of impact relative to the pendulum centerline between 53 ms to 88 ms after the time the peak translation-rotation value is reached.