Mechanisms and timing of injury to the thoracic, lumbar and sacral spine in simulated underbody blast PMHS impact tests

During an underbody blast (UBB) event, mounted occupants are exposed to high rate loading of the spine via pelvis. The objective this study was simulate UBB conditions and examine mechanisms injury in thoracic, lumbar sacral spine. Fourteen instrumented, whole-body, postmortem human subject (PMHS) experiments were performed using WSU-decelerative horizontal sled system. specimens positioned supine on a decelerative sled, which then impacted energy absorbing system concrete barrier. Variables included peak velocity time-to-peak for seat floor, presence or absence personal protective equipment (PPE) padding. Post-test CT scans autopsies identify severity injuries. Acceleration angular data collected at vertebra T1, T5, T8, T12, S1 used assess timing mechanisms. Additionally, joint time-frequency analysis (JTFA) spinal Z acceleration sacrum vertebrae developed with aim verifying fracture timing. Injuries observed attributed axial compression applied through pelvis, together flexion moment due offset center gravity torso, consistent UBB-induced combat injuries reported literature. estimation techniques discussed provide time interval when fractures predicted have occurred. Furthermore, approach serves as alternative methods acoustic sensors, force traces, strain gauges.