Experimental and numerical assessment of non-penetrating impacts on a composite protection and ballistic gelatine

In the field of Behind Armour Blunt Trauma (BABT), knowledge of the cavity morphology and transient pressure is important data for understanding this dynamic process. Blocks of ballistic gelatine are very often used to simulate human tissues in the case of impact studies. In this paper, the non-penetrating ballistic response of gelatine blocks shielded by a composite plate is experimentally and numerically analysed. Experimentally, the profiles of the transient cavity were captured in real time by a high-speed camera, while the transient pressures were simultaneously recorded by pressure gauges, incorporated into the gelatine blocks. Ballistic tests were conducted using a specific experimental setup with two types of bi-metallic projectiles. Numerical models were carried out with LS-DYNA® to assess the front face deformation of the gelatine blocks, the pressure wave amplitude and duration. The ballistic gelatine was described with an elastic-plastic model. Good correlation between the numerical and experimental results was obtained in terms of displacement with time of the temporary cavity. The tests and models showed the existence of several pressure waves propagating into the gelatine over a short delay. Damage mechanisms of both the projectiles and ballistic protections were compared to the models and showed good agreement.