Pelvic Response of a Total Human Body Finite Element Model During Simulated Injurious Under Body Blast Impacts

Abstract

Military operations in Iraq and Afghanistan have resulted in the increased exposure of military personnel to explosive threats. Combat-related pelvic fractures are a relatively new battlefield injury that poses a serious threat to military personnel. Injury prediction for these events continues to be a challenge due to the limited availability of blast-specific test studies and the use of established automotive-based injury criteria that do not directly translate to combat-related exposures. The objective of this study is to evaluate the pelvic response of the global human body models consortium (GHBMC) 50th percentile detailed male model (v4.3) in under body blast (UBB) loading scenarios. Nine simulations were conducted with mild or enhanced threat levels, and nominal or obtuse occupant positions. Cross-sectional force outputs from the superior pubic ramus (SPR), ilium, and sacroiliac (SI) regions were evaluated using previously developed injury risk curves (IRC). Additionally, maximum principal strain (MPS) data were extracted from the pelvic cortical bone elements. Results showed that shear force was the best predictor of fracture for the ischial and SI regions, while axial force was the best predictor for the SPR region. These outcomes were consistent with the load path of the simulated UBB events. The obtuse posture had higher peak force values for injurious and noninjurious outcomes for the SPR and SI region. The nominal posture had higher peak force values for noninjurious outcomes in the ischial region. These outcomes were supported by the MPS response present in these postures.