Parameter analysis and validation for Riemann-SPH simulation of hypervelocity impact on basalt material

To study the effects of parameters in smoothed particle hydrodynamics (SPH) simulations of hypervelocity impacts on basalt, numerical analysis and validation were performed using the Riemann-SPH method based on ground-based impact tests. By adjusting various simulation parameters, the influence of parameters on the simulation can be obtained. Results show that both algorithmic and material parameters significantly influence the simulation, with coupling between strength and damage models. Applying the artificial stress method helps suppress tensile instability in solid impacts. Using the Wendland C² kernel with a target of 2.5 particles within the smoothing length optimizes both accuracy and efficiency, and variable-resolution particle distribution improves performance by over 20 times. In simulations, the impactor may undergo a phase transition, and different model and parameter combinations can yield similar responses. It is recommended to employ the Lundborg strength model and the Benz-Asphaug stochastic damage model, which better represent the mechanical behavior of rocky materials, and to account for phase transitions. Parameter search should be constrained by reasonably known values to avoid large errors or non-uniqueness. With reasonable parameters, simulated crater size and momentum transfer factor match experiments within 10%–20% error. These strategies support SPH applications in asteroid defense and parameter selection.