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Top1. Introduction
Non-lethal kinetic energy (KE) weapons are a kind of non-lethal weapons which are mainly applied to stop people performing harmful actions and resolve the conflicts such as a single distraught individual or a large rioting crowd. They can rely on the flying kinetic energy of the projectiles to impact the body, so that the targets are too painful to resist, move or act. The goal of non-lethal KE rounds, like rubber, plastic and bag bullets is to deter an individual without causing serious or even fatal ballistic injury using blunt impact force. However, several cases of non-lethal KE projectiles resulting severe injuries and causing death because of their higher kinetic energy and specific kinetic energy have been reported (Bir et al. 2012). Therefore, there exists a need to have the greater insight into the human response subjected to high speed blunt impacts by KE projectiles of low mass and develop a special and biofidelic impact system in order to improve the KE weapons fighting capacity and assess the non-lethal uses of them in the field.
The injuries caused by non-lethal KE impact are blunt injuries (Bir 2015). Over the years, a number of different ballistic injury surrogates have been utilized: soap, gelatin, clay, animals, post-morterm human subjects (PMHS), and other materials. Although they provide the ability to maintain a permanent record and determination of energy transfer, they lack the visco-elastic nature of human tissue (Bir et al. 2012). Associated with the automotive crash, the dummy injuries are relatively large mass lower speed impacts (Lan et al., 2012; Nahum and Melvin, 2001; Ma and Yang, 2000; Cai, 2013). The research conclusions can’t be simply applied into the low mass, higher speed blunt ballistic injuries due to the nonhomogeneous, anisotropic, non-linear and viscoelastic characteristics of human tissue (Fung, 1993; Eck, 2006). Moreover, the impact effect of the non-lethal KE is closely related to impacted body parts (Figure 1). Clinical medical data shows that thorax region is one of the most vulnerable parts when non-lethal KE impact occurs (Bir and Eck, 2005; Ito et al., 2016; Steele et al., 1999; Mahajna et al., 2002; Hubbs and Klinger, 2002). Considering the less controllability, the quicker velocity decay, unstable performances and environmental influence of the non-lethal KE projectiles (Xiang et al., 2011), a special collaborative information system based on the hybrid III dummy for the evaluation of non-lethal KE impacting thorax region was proposed. The new system can measure the mechanical response data of dummy thorax effectively when KE projectiles impacting, show the effect of the non-lethal KE impact objectively and reasonably, and prove the feasibility of making use of the dummy to test non-lethal KE impact. The new system also avoids the problems that may be from laws, ethic, and difficulties in previous experiments.
Figure 1. Percentage of body injuries based on non-lethal kinetic energy impacts (Mahajna et al., 2002)