Predicting fractures due to blunt impact: a sensitivity analysis of the effects of altering failure strain of human rib cortical bone

Abstract

Finite element models of the thorax are used as tools to design restraint systems by predicting rib fractures. This study presents a sensitivity analysis of the effect of changing the plastic failure strain of a bilinear elastic, linear-hardening plastic constitutive model on the resulting number of rib fractures in a finite element model of the thorax. Plastic failure strain values from 0.6% to 1.8% were used, with frontal (4.9 m/s) and lateral (5.16 m/s) loading using a 23.4 kg blunt impactor. For both impacts, fractures generally decrease monotonically with increasing failure strain when material properties vary by location, while uniform material properties cause rib fracture numbers to oscillate.