CFR

CFR

572.74—Thorax assembly and test procedure.

(a) Thorax assembly. The thorax consists of the part of the torso assembly designated as SA 106C 030 on drawing SA 106C 001, sheet 2, Revision A, and conforms to each applicable drawing on SA 106C 001 sheet 10, Revision C (including Drawing number 6C-1610-1 thru -4, Revision A, titled “Screw Button Head Socket”, dated September 30, 1996, and Drawing number 6C-1021, Revision B, titled “Ballast, 6 Yr. Thoraxc (for 7267A)”, dated September 24, 1996), and sheet 11, Revision D (including Drawing number SA 6C-909, Revision A, titled “Cover-chest Accelerometer”, dated September 21, 1996, and Drawing number 6C-1000-1, Revision C, titled “Sternum Thoracic Weld Ass'y.”, dated September 24, 1996).

(b) Thorax assembly requirements. When the thorax is impacted by a test probe conforming to § 572.77(a) to 20 ±0.3 fps according to the test procedure in paragraph (c) of this section, the peak resultant accelerations at the accelerometers mounted in the chest cavity according to § 572.77(c) shall not be less than 43g and not more than 53g.

(1) The recorded acceleration-time curve for this test shall be unimodal at or above the 30g level, and shall lie at or above that level for an interval not less than 4 milliseconds and not more than 6 milliseconds.

(2) The lateral accelerations shall not exceed 5g.

(c) Thorax test procedure. The test procedure for the thorax is as follows:

(1) Seat and orient the dummy on a seating surface without back support as specified in § 572.78(c), and adjust the joints of the limbs at any setting (between 1g and 2g) which just supports the limbs' weight when the limbs are extended horizontally and forward, parallel to the midsagittal plane.

(2) Establish the impact point at the chest midsagittal plane so that the impact point is 2.25 inches below the longitudinal center of the clavicle retainer screw, and adjust the dummy so that the plane that bisects the No. 3 rib into upper and lower halves is horizontal ±1 degree.

(3) Place the longitudinal center line of the test probe so that it coincides with the designated impact point, and align the test probe so that at impact, the probe's longitudinal center line coincides (within 2 degrees) with the line formed at the intersection of the horizontal and midsagittal planes and passing through the designated impact point.

(4) Impact the thorax with the test probe so that at the moment of contact the probe's longitudinal center line falls within 2 degrees of a horizontal line in the dummy's midsagittal plane.

(5) Guide the test probe during impact so that there is no significant lateral, vertical, or rotational movement.

(6) Allow at least 30 minutes between successive tests.

[56 FR 57836, Nov. 14, 1991, as amended at 60 FR 2897, Jan. 12, 1995; 62 FR 44227, Aug. 20, 1997]