Energies of different assault tools in blunt force trauma

Due to the inherent ubiquity of objects capable of inflicting blunt force trauma, such injuries are a frequent occurrence in forensic investigations of violent crimes. While the injury patterns and medical consequences resulting from blunt force trauma have already been extensively researched, the forces or energies that act during impact are still largely unexplored. This study aims to determine the impact energies and moments of inertia (MOI) of various everyday items recently used as assault weapons. Five different tools but with similar MOI's were examined, namely a crutch, a vacuum cleaner tube, a nylon hammer, a cooking pot and a frying pan. A total of 500 strikes were performed by 10 volunteers which resulted in the following average energy transfers from the tools to the target medium: 75.5 ± 10.7 J for the crutch, 70.6 ± 9.2 J for the nylon hammer, 63.4 ± 9.5 J for the cooking pot, 61.2 ± 10.9 J for the vacuum cleaner tube, and 53.2 ± 9.3 J for the frying pan. This data allows, in conjunction with energy limit value tables for specific injuries or bone fractures, to determine whether a hit with the corresponding assault tool could potentially have led to a certain injury or death [1,2]. The impact energies generated as a function of the physical properties of the striking objects or of the perpetrator, may serve as evidence in the forensic assessment and evaluation of injury risks in legal cases. This study demonstrates a clear correlation between the MOI, or the individual's body height, and the impact energies. These experimental findings make it possible to interpolate the impact energies expected from a questioned tool based on its physical properties and the biophysical characteristics of the assailant, thereby enabling a more informed estimation of the associated injury potential.