Numerical analysis of ballistic impact through FE and SPH methods

In the defense and aerospace industries, structures are designed to resist ballistic impact loads. Experimental analysis of ballistic impact has been conducted successfully for many years, and alternatively, numerical techniques have been employed to reduce the experimental cost. In this study, the ballistic impact of metallic materials is addressed with both finite element (FE) and smoothed particle hydrodynamics (SPH) methods. A single-shot ballistic impact model consisting of a deformable plate and a rigid projectile is developed. These two methods are compared using Johnson-Cook (JC) and Modified Mohr-Coulomb (MMC) damage models. Lode parameter dependent MMC damage criterion is implemented in the user-defined field (VUSDFLD) for damage analysis. Various numerical setups with varying target thickness, impact velocity, projectile nose shape and impact angle of the projectile, are generated. The damage response of the plate target according to the impact angle and the nose shape and the effect of ballistic impact parameters on the residual velocity is discussed in detail. The results are compared with the experimental results from the literature. FE method is found to be more consistent than SPH method in the prediction residual velocity. MMC damage model is better in agreement with experimental data than JC damage model. A linear decrease in residual velocity is observed with increasing thickness of target except the JC model used with FE method. Moreover, blunt projectiles are more sensitive to change in the impact angle than hemispherical and ogival projectiles. Increase in impact angle cause a reduction in residual velocity for all three projectile.