Numerical Investigation of Behind the Armour Ballistic Trauma of Ceramic-Composite Armour System

A lightweight ceramic-based armour system must arrest bullet penetration and dissipate a large amount of impact energy. If the momentum transferred to the human body, also known as behind armour ballistic/blunt trauma (BABT), exceeds the threshold value, a non-penetrated target may cause serious injury or even death of the wearer. In this study, the impact response of body armour comprised of silicon carbide (SiC) plate backed with unidirectional ultrahigh molecular weight polyethylene (UD-UHMWPE) fibre composite struck at an impact velocity of 500 m/s is numerically investigated. A gelatin block is used as a surrogate model to simulate the human torso. The commercial finite element software ASNSYS/AUTODYN® is used to numerically analyse three-dimensional non-linear deformations of the system, utilizing the full integration rule to determine the elemental matrices. The Johnson–Cook, Johnson-Holmquist, and orthotropic material behaviour were utilized for the projectile, ceramic, and composite materials, respectively. Gelatin is modelled as a viscoelastic material and follows Mie-Grüneisen equation of state and Johnson–Cook failure model. Values of the material parameters were taken from the available literature. The deformation mechanism of the ceramic-composite target was evaluated. It is found that the maximum depth of cavity formed in the gelatin block is 11.65 mm. The impact pressure associated with momentum transferred to the human tissue is also calculated. The peak pressure of 14.2 MPa was observed near the cavity region, which gradually decreases at the rear face of the gelatin block. The maximum pressure and depth of the temporary cavity generated in the gelatin computed from the present analysis can be used to determine the degree of the body injury induced by impact.