On propagation characteristics of shock waves generated under hypervelocity impact

A numerical simulation model based on Smoothed-Particle Hydrodynamics (SPH) was developed, for modeling a Hypervelocity Impact (HVI) scenario in which an aluminum target plate of 2 mm thickness, was penetrated by an aluminum sphere of 3 mm diameter, at an initial velocity of 4117 m/s. The meshless nature of the SPH algorithm has been demonstrated to overcome the inefficiency of traditional Finite Element Methods (FEM) in tackling large structural distortion problem to warrant the accuracy when handling HVI. With the algorithm, the accordingly generated shock waves under the HVI were captured by calibrating the strains at representative gauging points along the shock wave propagation path, and the signals were examined quantitatively in both the time and the frequency domains, to extract wave signal features. The simulated debris cloud on HVI was observed to match well with both the experiments and simulation results. It has been concluded that in the regions near the impact point, a shock wave with high velocity was produced; as propagation distance increases, the shock waves can be described as the symmetric and antisymmetric plate-guided modes, propagating at distinct velocities, and frequency bands.