Session: 07-01-01: Injury Risk Assessment due to Blunt Impact

Paper Number: 165809

Assessment of Thoracic Injury From Kinetic Impact Projectiles Using Numerical Simulations 

Law enforcement agencies have been using non-lethal kinetic impact projectiles (KIPs) for a long time as a means of riot control or to incapacitate an individual. Though KIPs are designed to avoid causing serious injuries, there have been reports of major injuries, including fatalities. KIPs come in various sizes and shapes. The smaller caliber KIPs have a higher probability of causing penetrative injury, while the larger caliber ones have a tendency of causing internal injury because of the blunt impact. The thoracic region, which contains most of the vital organs, is most likely to be hit by KIPs since it has a large surface area. In this paper numerical simulations are used to explore injury to thoracic region due to the blunt impact of large caliber KIPs.

To understand the injury risk associated with blunt ballistic impact, several Finite Element (FE) human body models have been developed and used, but those models are not freely available. Toyota Motor Corporation developed a FE human body model called the Total Human Model for Safety (THUMS) to simulate injuries related to vehicle collisions, including vehicles impacting pedestrians, and the model is freely available. This paper explores the feasibility of using the THUMS model and the commercial software ANSYS LS-DYNA to determine injuries caused by KPIs impacting the thoracic region of an adult 50th percentile male. The numerical simulations aim to predict the biomechanical response of the thorax region to impacts from two types of large-caliber KIPs: the eXact iMpact and the Flash-Ball projectiles. The eXact iMpact projectile has a 40 mm diameter, featuring a cylindrical geometry with a foam nose and a plastic rear, and a reported muzzle velocity of 95 m/s. In contrast, the Flash-Ball projectile is spherical, with a diameter of 44 mm and a muzzle velocity ranging from 85 to 125 m/s.

Finite element simulations were conducted to assess the thoracic response to impacts from the two projectiles mentioned above at two different locations and at two different incident angles at each location. The resulting thorax displacement-time curves were analyzed to evaluate the mechanical response and potential injury risk. In addition, three impact scenarios using the L5 projectile impacting the mid-sternum region corresponding to the experimental study conducted by Bir, Viano, and King, were simulated. The biomechanical response corridors developed by those authors were applied to validate the numerical simulation results, ensuring the model’s response aligned with established experimental data. The Viscous Criterion (VC), which is calculated by multiplying the relative compression of the impacted thorax area with the velocity of compression, was also used to evaluate injuries caused by the blunt ballistic impact. Finally, the Abbreviated Injury Scale (AIS) from level 1 to 6 was used to determine injury severity based on the values of the VC.

Presenting Author: Karim Muci-Kuchler Texas State University

Presenting Author Biography: Dr. Karim Muci-Kuchler is a Professor and Mechanical Engineering Program Coordinator at the Ingram School of Engineering of Texas State University. Before joining Texas State University, he was a Professor of Mechanical Engineering and Director of the Experimental and Computational Mechanics Laboratory at the South Dakota School of Mines and Technology. He received his Ph.D. in Engineering Mechanics from Iowa State University in 1992. His main interest areas include Computational Mechanics, Solid Mechanics, Product Design and Development, and STEM Education. He has taught several different courses at the undergraduate and graduate level, has over 90 publications, is co-author of one book, and has done consulting for industry in Mexico and the US. Dr. Muci-Kuchler is an ASME Fellow.

Authors:

Arafat Anzir Texas State University, Ingram School of Engineering
Karim Muci-Kuchler Texas State University