Numerical Study on Ballistic Resistance of Whipple Shield Under Different Ellipsoid Projectiles Against Hypervelocity Impact

Numerical Studies are carried out to study the ballistic resistance of Whipple shields at hypervelocity impact under different shapes of the projectiles. The Whipple shields consist of a bumper plate and rear wall in which both the plates are made of Al-2024-T3 with sizes of 100 × 100 × 1 and 150 × 150 × 2 mm respectively. The material of the projectile is also made with Al-2024-T3. The shape factor (SF) is defined by the L/d ratio, for the symmetrically ellipsoid shape projectile. A 3-dimensional smooth particle hydrodynamic (SPH) model is created in Ls-Dyna and the model is calibrated with the experimental results. Calibration of the SPH model is done by using the Johnson cook (JC) material model for Whipple shields and projectiles material. These calibrated models are used to study the shape effect of ellipsoid shape projectiles. Maximum residual velocity is observed at shape factor 4.46 under high-velocity impact. However, in hypervelocity impact, the ballistic resistance of the Whipple shield decreases with an increase in SF. It is also observed that the residual velocity is minimum for SF = 0.28 for hypervelocity impact.