Failure Analysis of Human Lower Extremity During Lateral Blast: A Computational Study

In recent military warfare, lower extremities (LE) accounted for 70% of the total combat fractures [1, 2]. Despite orthopedic blast injuries on the lower extremities being the most prevalent, there is a dearth of human cadaver studies investigating the relevant injury mechanism. To the best of the authors’ knowledge, no experimental investigation has been performed on human cadaver LE to evaluate a lateral blast's effect. In this research work, numerical studies have been performed to evaluate the injury mechanism of a human lower extremity subjected to a lateral blast. Finite element model predictions are observed to be in good agreement with Hull and Cooper’s pioneer experimental study on a goat limb and clinical human injury patterns [3]. Direct blast wave coupling with proximal tibiae has been observed to cause very high strain rates, resulting in bones’ splintering and a characteristic oblique fracture. Based on simulation results, it has been proposed that extremely high strain rates associated with a lateral blast are localized and concentrated at the proximal end of the tibiae. The minimum safe distance to avoid lower extremity injuries has been presented. There is a paucity of experimental data available for close field blast studies due to difficulty in accurately capturing the response parameters involved. Numerical results corroborated by experimental and clinical findings, bring a paradigm shift in our understanding of lateral blast injuries.