Title 49

SECTION 572.213

572.213 Neck assembly and test procedure.

§ 572.213 Neck assembly and test procedure.

All assemblies and drawings referenced in this section are contained in Drawings and Specifications, incorporated by reference, see § 572.210.

(a)(1) The neck and headform assembly for the purposes of the fore-aft neck flexion and lateral neck flexion qualification tests, as shown in figures W3 and W4 in appendix A to this subpart, consists of the headform (drawing 020-9050, sheet 1) with angular rate sensor installed (drawing SA572-S58), six-channel neck/lumbar load cell (drawing SA572-S8), neck assembly (drawing 020-2400), neck/torso interface plate (drawing 020-9056) and pendulum interface plate (drawing 020-9051) with angular rate sensor installed (drawing SA572-S58).

(2) The neck assembly for the purposes of the neck torsion qualification test, as shown in figure W5 in appendix A to this subpart, consists of the neck twist fixture (drawing DL210-200) with rotary potentiometer installed (drawing SA572-S51), neck adaptor plate assembly (drawing DL210-220), neck assembly (drawing 020-2400), six-channel neck/lumbar load cell (drawing SA572-S8), and twist fixture end plate (drawing DL210-210).

(b) When the neck and headform assembly as defined in paragraph (a)(1) of this section, or the neck assembly as defined in paragraph (a)(2) of this section, is tested according to the test procedure in paragraph (c) of this section, it shall have the following characteristics:

(1) Fore-aft neck flexion qualification test. (i) Plane D, referenced in figure W3 in appendix A to this subpart, shall rotate in the direction of pre-impact flight with respect to the pendulum's longitudinal centerline between 69.5 degrees and 81.0 degrees. During the time interval while the rotation is within these angles, the peak moment measured by the neck transducer (drawing SA572-S8) shall have a value between 41.5 N-m and 50.7 N-m.

(ii) 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 45 to 55 ms after the time the peak rotation value is reached.

(iii) All instrumentation data channels are defined to be zero when the longitudinal centerline of the neck and pendulum are parallel.

(iv) The headform rotation shall be calculated by the following formula with the integration beginning at time zero:

Headform rotation (deg) = ∫ [(Headform Angular Rate)y−(Pendulum Angular Rate)y] dt

(v) (Headform Angular Rate)y is the angular rate about the y-axis in deg/sec measured on the headform (drawing 020-9050, sheet 1), and (Pendulum Angular Rate)y is the angular rate about the y-axis in deg/sec measured on the pendulum interface plate (drawing 020-9051).

(2) Lateral neck flexion qualification test. (i) Plane D, referenced in Figure W4 in appendix A to this subpart, shall rotate in the direction of pre-impact flight with respect to the pendulum's longitudinal centerline between 76.5 degrees and 87.5 degrees. During the time interval while the rotation is within these angles, the peak moment measured by the neck transducer (drawing SA572-S8) shall have a value between 25.3 N-m and 32.0 N-m.

(ii) 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 61 to 71 ms after the time the peak rotation value is reached.

(iii) All instrumentation data channels are defined to be zero when the longitudinal centerline of the neck and pendulum are parallel.

(iv) The headform rotation shall be calculated by the following formula with the integration beginning at time zero:

Headform rotation (deg) = ∫ [(Headform Angular Rate)y−(Pendulum Angular Rate)y] dt

(v) (Headform Angular Rate)y is the angular rate about the y-axis in deg/sec measured on the headform (drawing 020-9050, sheet 1), and (Pendulum Angular Rate)y is the angular rate about the y-axis in deg/sec measured on the pendulum interface plate (drawing 020-9051).

(3) Neck torsion qualification test. (i) The neck twist fixture (drawing DL210-200), referenced in figure W5 in appendix A to this subpart, shall rotate in the direction of pre-impact flight with respect to the pendulum's longitudinal centerline between 74.5 degrees and 91.0 degrees, as measured by the rotary potentiometer (drawing SA572-S51). During the time interval while the rotation is within these angles, the peak moment measured by the neck transducer (drawing SA572-S8) shall have a value between 8.0 N-m and 10.0 N-m.

(ii) The decaying neck twist fixture 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 85 to 102 ms after the time the peak rotation value is reached.

(iii) All instrumentation data channels are defined to be zero when the zero pins are installed such that the neck is not in torsion.

(c) The test procedure for the neck assembly is as follows:

(1) Soak the neck assembly in a controlled environment at any temperature between 20.6 and 22.2 °C and a relative humidity between 10 and 70 percent for at least four hours prior to a test.

(2)(i) For the fore-aft neck flexion test, mount the neck and headform assembly, defined in paragraph (a)(1) of this section, on the pendulum, described in figure 22 to § 572.33, so that the midsagittal plane of the headform is vertical and coincides with the plane of motion of the pendulum, and with the neck placement such that the front side of the neck is closest to the honeycomb material as shown in figure W3 in appendix A to this subpart.

(ii) For the lateral neck flexion test, the test is carried out in the direction opposing the primary load vector of the ensuing full scale test for which the dummy is being qualified. A right flexion test set-up that is used to qualify the dummy for an ensuing full scale right side impact is depicted in figure W4 in appendix A to this subpart. A left flexion test set-up would be depicted by a mirror image of all components beneath the pendulum interface plate in Figure W4. Mount the neck and headform assembly, defined in paragraph (a)(1) of this section, on the pendulum, described by figure 22 to § 572.33, so that the midsagittal plane of the headform is vertical and coincides with the plane of motion of the pendulum, and with the neck placement such that the right (or left) side of the neck is closest to the honeycomb material as shown in figure W4.

(iii) For the neck torsion test, the test is carried out in the direction opposing the primary load vector of the ensuing full scale test for which the dummy is being qualified. A right torsion test set-up that is used to qualify the dummy for an ensuing full scale right side impact is depicted in figure W5 in appendix A to this subpart. A left flexion test set-up would be a mirror image of that shown in figure W5. Mount the neck assembly, defined in paragraph (a)(2) of this section, on the pendulum, described by figure 22 to § 572.33, as shown in figure W5.

(3)(i) Release the pendulum and allow it to fall freely from a height to achieve an impact velocity of 4.7 ± 0.1 m/s for fore-aft flexion, 3.8 ± 0.1 m/s for lateral flexion, and 3.6 ± 0.1 m/s for torsion, measured by an accelerometer mounted on the pendulum at time zero.

(ii) Stop the pendulum from the initial velocity with an acceleration vs. time pulse that meets the velocity change as specified in table 1 to this section. Integrate the pendulum accelerometer data channel to obtain the velocity vs. time curve beginning at time zero.

(iii) Time zero is defined as the time of initial contact between the pendulum striker plate and the honeycomb material.

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