Riemann-SPH simulation of hypervelocity impact on basalt material: parameter analysis and validation

To study the influence of parameters in SPH simulations of hypervelocity impacts on basalt material, numerical simulation and validation were performed based on the Riemann-SPH method using experimental data from ground-based hypervelocity impact tests on basalt. It was found that the SPH simulation results are significantly affected by both algorithmic and material model parameters, and there is an interaction between the effects of the material strength model and damage model. Specific findings reveal that applying an artificial stress method in hypervelocity impact SPH simulations helps prevent tensile instability in solid impact simulations; choosing an appropriate expected particle number within the smoothing length and using a variable-resolution particle distribution method can balance computational accuracy and efficiency. In ground-based simulations, different material strength and damage models can produce similar impact responses under varying cohesive and tensile strengths, and selecting a model with lower accuracy may lead to misinterpretation of material parameters and physical laws. Additionally, multiple parameter combinations in the strength and damage models can yield similar simulation outcomes, indicating that incorrect parameter choices may still yield results close to experimental findings. When model parameters are set reasonably, the simulated crater size and momentum transfer factor are within 10-20% error range compared to experimental data. These parameter selection methods provide guidance for conducting SPH simulations of hypervelocity impact for asteroid defense and for making informed parameter choices.