Experimental study of the mechanical response of a physical human surrogate thoracic model impacted by a rubber ball

Abstract

A physical human surrogate thoracic model was developed using biosimulant materials and the same anthropometry as a healthy adult male, and ballistic tests targeting the physical thoracic model were conducted using a rubber ball with a diameter of 16 mm at low (85-90 m/s), moderate (110-115 m/s), and high (130-135 m/s) velocities. The mechanical response to impact was recorded with sensors embedded into the organs. The internal organs pressure waves exhibited blast-like characteristics for the physical mode. Three parameters of initial pressure in organ were determined from the measured data: internal organs maximum pressure (Pmax), internal organs maximum pressure impulse (PImax), and the internal organs pressure gradient (dP/dt). The three parameters showed the same trend for the three different impact velocities, and these results represented a significant step in developing an understanding of the energy transfer characteristics of ballistic impacts to the human thorax. The results demonstrate the discriminating abilities of the model between threat levels, impact velocities and impact locations. It is found the first time to construct a physical human surrogate thoracic model dedicated to study the mechanism of the blunt injury impacted by the less-lethal ammunition, and the results of this research provided the function of a physical surrogate model of the human thorax which can transfer energy and propagate pressure waves during rubber bullet impacts. The model could be used to evaluate the efficiency of less-lethal ammunition before using it in the course of law enforcement, and the model provides a tool for forensic verification and validation.