Automatic Mesh-Generation (FEM/SPH) for HVI-Simulations of Arbitrary Rotational Symmetric Impactors

Abstract

For the numerical description of high velocity impact, Smooth-Particle-Hydrodynamics (SPH) has gained more and more interest. The standard Lagrangian Finite-Element (FE) approach has difficulties in describing large deformations and fracture. However, a simulation based on SPH only is very expensive due to the small size of the particles. A well adopted solution to this is to couple both methods, using SPH only where it is necessary, and capturing the outer boundary conditions with a bias FE-mesh correctly - without considerable extra computational cost. We apply such a hybrid approach in LS-DYNA® for the characterization of threats in terminal ballistics. Different meshing approaches for the projectile and target were implemented to guarantee an optimal initial condition. The particle size and the required size of the SPH-region were studied to exclude discretization effects. Exemplarily, a projectile surrogate with simplified geometry is investigated for a fixed impact velocity and two different angles of obliquity. A qualitative comparison between experiments, observed with X-ray cinematography, reveals a good potential of this approach towards predicting fracture and ricochet during high velocity impact events.