Predicting the damage on a target plate produced by hypervelocity impact using a decoupled finite particle method

Hypervelocity impact (HVI) is associated with large deformations of structures, phase transitions of materials and scattered debris cloud. It is a great challenge to accurately model the HVI process and predict the damage produced by HVI for conventional numerical methods. In this paper, a recently developed corrective smoothed particle hydrodynamics (SPH) method, decoupled finite particle method (DFPM), is extended to model HVI problems. Validation examples show that DFPM is as flexible as SPH while having much better performance in improving accuracy and removing tensile instability. DFPM is also very attractive for modeling problems with extremely disordered particle distribution (e.g., HVI) as no matrix inversion is required. DFPM is then applied to model the penetration of a sphere on a target plate at various impact velocities and impact angles. It is found that as the impact velocity increases, the hole size increases accordingly and maintains basically constant in a steady state after the impact velocity reaches a critical value. Based on extensive DFPM simulation results, novel formulae are given for predicting the hole size produced by normal and oblique HVIs, which can reproduce experimental data and shows better performance than existing empirical formulae in a wider range of impact velocity.