Parametric study in analysing the effect of spinning on the deformable projectiles undergoing impact

Abstract

Projectiles spin as they move through the air due to the rifled barrels. The projectile consists of both translational and rotational velocities called spinning when the projectile reaches the target. In this parametric study dealing with influencing factors such as residual velocity, residual mass, residual energy etc. in analysing the effect of spinning on deformable projectiles undergoing impact are carried out based on the Finite Element Analysis (FEA) using commercial LS-DYNA software. The projectile and the target materials are considered deformable and modelled based on Johnson-Cook (JC) strength and failure models. Initially, the model is validated by using the experimental results available in the literature. The validated model is extended to study the effect of above cited parameters including projectile materials and target obliquity etc. on projectile spinning. In the present research, steel and lead materials are considered for the projectile. Al 7075-T651 material is considered for the target. The residual energy which is a function of residual mass and residual velocity has been computed for the projectile with different materials. It has been found that the projectiles made up of lead experienced more damage with the spin compared to steel. Accordingly, the lead material is not suitable for the projectile with spinning. Hence, the subsequent analysis is extended with the projectile made up of steel only and allowed to impact the target with different orientations. It has been observed that the projectile path is slightly deviating when it is impacted on an inclined target compared to normal impact conditions. So, the energy required to defeat the target with spin and without spin is evaluated to understand the spinning effectiveness. Based on the results obtained, it can be concluded that, for 90° target inclination, 1x spin is favourable compared to without spin that is, 0x. As the target inclination is decreased further, 2x spin is preferred compared to no spinning.