Side impact PMHS thoracic response with large-volume air bag.

OBJECTIVE: The objective of this study is to assess the response of postmortem human subjects (PMHS) to a large-volume side air bag in a fully instrumented and well-controlled side impact test condition. METHODS: Three adult male PMHS were subjected to right-side pure lateral impacts. Each stationary seated subject was struck at 4.3 ± 0.1 m/s by a rigid wall installed on a 1700-kg rail-mounted sled. Each subject was held stationary by a system of tethers until immediately prior to being impacted by the moving wall. A large side air bag was mounted to the wall and deployed so that it was fully inflated at the time it contacted the subject's right side. The load wall consisted of an adjustable matrix of 15 individual plates, each supported by a 5-axis load cell that recorded the interaction between the subject and impacting wall. Two-dimensional (external) torso deformation was provided by a chest band that encircled the torso at the level of the sixth rib laterally. Triaxial acceleration was measured at the head, spine, and sacrum via 3 orthogonal accelerometers mounted to the same bone-mounted hardware that held the marker clusters used for kinematic analysis. RESULTS: Peak pelvic load normal to the wall averaged 6.8 kN, which was over 5 times that recorded for the shoulder (1.3 kN) and the thorax (1.2 kN). Lateral chest deflection ranged from 9 to 21 mm. Two of the 3 subjects sustained 2 and 9 fractures, respectively. CONCLUSIONS: Two of the 3 PMHS sustained rib fractures despite low levels of thorax deflection. We attribute this finding to individual variability in subject injury tolerance. Other response parameters exhibited lower levels of variability and characterize PMHS response to a potentially beneficial side impact countermeasure. Supplemental materials are available for this article. Go to the publisher's online edition of Traffic Injury Prevention to view the supplemental file.