The Development of Biomechanically based Criteria of Rib Fracture from KE-NLW Impact

Biomechanically-based rib fracture criteria were developed in this study for high-speed impacts. There currently exists no criterion for predicting the potential of rib fracture under KE-NLW impacts. The criterion developed for thoracic injury prediction under car crash conditions, the so-called viscous criteria VC, did not work for KE-NLW impacts when validated against animal test data. This can be explained by the fact that VC is an empirical criterion that is based on animal tests using impactors that were much heavier but slower than NLW. A detailed finite element model FEM of ribs was developed based on geometry constructed from high-resolution CT images. Correlation curves using stresses as correlates were developed and are provided in the report. The correlations fitted the animal test data very well and the threshold values are consistent with bone strength data found in the literature.