572.146—Test conditions and instrumentation.

(a) The test probe for thoracic impacts, except for attachments, shall be of rigid metallic construction and concentric about its longitudinal axis. Any attachments to the impactor such as suspension hardware, and impact vanes, must meet the requirements of § 572.144(c)(7) of this part. The impactor shall have a mass of 1.70 ±0.02 kg (3.75 ±0.05 lb) and a minimum mass moment of inertia 164 kg-cm 2 (0.145 lb-in-sec 2) in yaw and pitch about the CG of the probe. One-third ( 1/3) of the weight of suspension cables and any attachments to the impact probe must be included in the calculation of mass, and such components may not exceed five percent of the total weight of the test probe. The impacting end of the probe, perpendicular to and concentric with the longitudinal axis of the probe, has a flat, continuous, and non-deformable 50.8 ±0.25 mm (2.00 ±0.01 inch) diameter face with an edge radius of 7.6/12.7 mm (0.3/0.5 in). The impactor shall have a 53.3 mm (2.1 in) dia. cylindrical surface extending for a minimum of 25.4 mm (1.0 in) to the rear from the impact face. The probe's end opposite to the impact face has provisions for mounting an accelerometer with its sensitive axis collinear with the longitudinal axis of the probe. The impact probe has a free air resonant frequency not less than 1000 Hz limited to the direction of the longitudinal axis of the impactor.