Investigation of bullet penetration in ballistic gelatin via finite element simulation and experiment

Abstract

To qualitatively understand the deformation processes and damages in the human body caused by high-speed impact, we conducted experimental and computational investigations for bullet penetration into viscoelastic ballistic gelatin blocks. Because it is difficult to measure the strain rate-dependent material properties of viscoelastic gelatin blocks during high-speed impact, the material properties that are indirectly defined by the stress relaxation test were used for the computational simulation. We also conducted some firing experiments and analyzed the deformation processes of the structures. In particular, the passing through times and the shapes of the temporary and permanent cavities inside the ballistic gelatin blocks were analyzed and compared. This data reveals that the employed material models, with some modifications for the FE simulation, are sufficient for predicting the high-speed impact behaviors. To investigate the shapes of the permanent cavities and fragments made by bullets inside the gelatin blocks, two-dimensional sectional images were taken by an industrial CT scanner and a three-dimensional CAD model was constructed based on these images.