Numerical and experimental study of the impact of small caliber projectiles on ballistic soap

Terminal ballistics deals with interactions between targets and projectiles. One of the areas of interest is wound ballistics, where one studies the interaction between a projectile (a bullet or a fragment) and the human body. Soap and gelatin are commonly used materials for simulating soft human body tissue in wound ballistics experiments. They are to be considered as tools for comparing the effectiveness of different projectiles. The department of weapon systems & ballistics of the Belgian Royal Military Academy is examining to what extent the Autodyn hydrocode can be used as a numerical tool for simulating the penetration of military bullets into ballistic soap. This article presents the philosophy and the results of the project's first phase i.e. the use of Autodyn for simulating the penetration of a steel sphere into a block of ballistic soap as a result of a normal impact at different velocities. A series of experiments (real firings) have been performed in the laboratory of the department. They serve as a reference and validation tool for the numerical approach. The latter is characterized by the specific problem of accurate material modeling of the soap. The application of a stepwise parametric study of material models and parameters has resulted in numerical simulations which fit quite well with experiments.