Impact energy of everyday items used for assault.

Blunt force is a frequently used type of violence especially because it can be performed with basically every object of our daily lives or with bare hands or feet. The injuries and medical consequences have been widely examined, whereas the forces and especially the energies acting on impact have rarely been analyzed. The aim of the present study is to provide the impact energy and its ranges of four longish everyday items with different characteristics for male and female offenders. Additionally, the moment of inertia (MOI) for all the objects was calculated and its influence on the energy determined. A combination wrench, aluminum pipe, golf club, and spade were chosen as representatives of the four categories short, medium length with the center of mass (COM) in the middle, medium length with the COM close to the hitting point, and long and heavy. A total of 880 strikes have been performed by 11 volunteers. The results show the mean energy values of wrench, pipe, golf club, and spade for men of 51.1, 74.4, 93.5, and 166.7 J. For women, the results are 33.0, 41.0, 56.5, and 76.8 J. Knowing the energy thresholds for certain fractures and injuries, these results help to assess whether a claimed hit may have caused the fracture or injury or not.

The influence of striking object characteristics on the impact energy.

A common form of violence investigated in legal medicine is blunt trauma caused by striking with different objects. The injuries and medical consequences have been widely examined, whereas the forces and especially the energies acting on impact have rarely been analyzed. This study focuses on how the impact energy of different striking objects depends on their characteristics. A total of 1170 measurements of horizontal strikes against a static and relatively heavy pendulum have been acquired with 13 volunteers. The main focus was laid on how the weight, the length, and the center of mass of the different striking objects influenced the striking energy. The results show average impact energies in the range of 67.3 up to 311.5 J for men with an optimum weight of about 1.3 kg with its center of mass in the far end quarter for a 1-m-long striking object. The average values for women range from 30 to 202.6 J, with an optimum weight between 1.65 and 2.2 kg and similar settings for the center of mass as the men. Also, the impact energies are getting higher with shorter object lengths and reach a maximum at a length of about 0.3 to 0.4 m. The male volunteers' impact energy was on average by 84.2% higher than the values of the female volunteers, where the impact masses were very similar and the impact velocities played the key role.