The purpose of this study is to help understand the thoracic response and injury mechanisms in high-energy, limited-stroke, lateral velocity pulse impacts to the human chest wall. To impart such impacts, a linear impactor was developed which had a limited stroke and minimally decreased velocity during impact. The peak impact velocity was 5.6 +/- 0.3 m/s. A series of BioSID (biofidelic side impact dummy) and cadaver tests were conducted to measure biomechanical response and injury data. The conflicting effects of padding on increased deflection and decreased acceleration were demonstrated in tests with BioSID and cadavers. The results of tests conducted on six cadavers were used to test several proposed injury criteria for side impact. This test methodology captured and supported a contrasting trend of increased chest deflection and decreased Thoracic Trauma Index (TTI) when padding was introduced. The study suggested that chest deflection or the energy generated in a lateral velocity pulse impact, correlated with the number of rib fractures better than acceleration or the viscous response of the struck-side rib cage. Chest deflection (Dmax) or stored energy (SEC) correlated well to the number of rib fractures. The hypothesis for injury assessment using Maximum Stored Energy Criterion (SEC) was supported by the BioSID and cadaver test results. (A)
Abstract