Preliminary Impact and Injury Response of Varied Anthropometry Postmortem Human Surrogates in Frontal Sled Tests

Robust restraint system design requires effectiveness across varied anthropometries. Biofidelity reference datasets of postmortem human surrogates (PMHS), a necessary component of informing and assessing restraint system design, exist for the midsize males and small females, but there is limited research for other anthropometries such as the midsize female and obese populations. The goal of this study was to evaluate the kinematic and injury response of midsize female, elderly midsize female, obese female, and obese male PMHS in upright frontal impacts in a simplified restraint environment. The test condition in this study was a full-frontal 30 km/h impact. The test fixture consisted of a rigid seat, knee bolster, footpan, a custom 3 kN shoulder belt force limiter, and separate shoulder and lap belts. Twelve tests were performed with PMHS of varied anthropometries: three per occupant type (midsize female, elderly midsize female, obese female, and obese male). The restraint environment limited the movement of the lower extremities, isolating the thoracic response. Shoulder belt lengths and positioning varied by occupant type. Peak shoulder belt force values ranged between 2.8 and 4.4 kN. Differences in soft tissue distribution (including the hips, abdomen, and breasts) affected both the pre-test path of the shoulder belt on the thorax and the belt’s subsequent motion relative to the thorax during the test. Rib fractures were observed across all four occupant types ranging from 0 to 19 fractures. Occupant anthropometry affected the impact and injury response of the PMHS in this study, demonstrating the breadth of the population over which restraint system robustness is required.