Abstract:
This doctoral dissertation summary by Andrius Vilkauskas presents a comprehensive investigation into the ballistics of small arms ammunition bullets using a combination of computational modeling and experimental methods. The research aims to develop, verify, and validate computational models for bullets and their interaction with targets, and to investigate the dynamic properties of these processes. The study addresses interior, exterior, and terminal ballistics, with a particular emphasis on fluid dynamics and high-velocity impact dynamics. The author's methods integrate theoretical principles from solid mechanics, fluid dynamics, and high-velocity impact dynamics with experimental investigations of powder gas pressure and bullet velocity. For interior ballistics, a new computational model for the bullet's resistance force in a rifled barrel is introduced by using the concept of a smooth barrel equivalent. This model, when integrated with experimentally obtained powder gas pressure-time data, provides a more accurate estimation of bullet motion, with the calculated muzzle velocity differing from the experimental value by only 0.05%. For terminal ballistics, the research focuses on the behavior of materials under high-velocity impact, which is a key aspect of hydrodynamics. The study employs the finite element software LS-DYNA to simulate the interaction of a steel rod with a steel plate, and a bullet with both solid and textile targets. The research identifies material dynamic properties and Cowper-Symonds relation constants for steel AISI 1020, finding that friction can be negligible in certain high-velocity, short-duration impacts. The models developed show high accuracy in predicting residual velocity for a range of initial velocities. The research also introduces a new mezzo-mechanical model for textile targets, which simulates individual yarns and their interaction, demonstrating the significant role of friction between fabric layers in providing ballistic resistance. The findings provide valuable tools for engineering applications, such as the design of ammunition and light-weight body armor.
