Sensibility study of viscous criterion for kinetic energy non-lethal projectile thoracic impacts

There are two main injury mechanisms that have to be considered when the thorax is subjected to kinetic energy non-lethal projectile impacts: skin penetration and blunt trauma. The thoracic injury is one of the most important blunt traumas. In order to predict the lethality of a thoracic non-lethal impact, different injury criteria and tolerance limits have been defined, based on animal and cadaver testing. The viscous criterion - (VC)_max - is considered for thorax injury as widely accepted and used in the non-lethal community. It is based on the thorax deflection and thorax deflection rate during the impact. Nevertheless there are many parameters that can influence the calculation of (VC)_max such as the projectile impact yaw angle and the location of the thorax deflection measurement. Experimentally, normal impacts are generally considered, which differ from real shootings. Moreover, it is difficult to predict with accuracy the location where (VC)_max will be maximal. However, thanks to numerical simulations, we can take into account the general case and deduce practical guidelines.