Fourier amplitude sensitivity test applied to dynamic combined finite‐discrete element methods–based simulations

Summary Fracture propagation plays a key role for a number of applications of interest to the scientific community, from dynamic fracture processes like spallation and fragmentation in metals to failure of ceramics, airplane wings, etc. Simulations of material deformation and fracture propagation rely on accurate knowledge of material characteristics such as material strength and the amount of energy being dissipated during the fracture process. Within the combined finite‐discrete element method (FDEM) framework material fracture behavior is typically described through a parametrized softening curve, which defines a stress‐strain relationship unique to each material. We apply the Fourier amplitude sensitivity test to explore how each of these parameters influences the simulated damage processes and to determine the key input parameters that have the most impact on the model response. We present several sensitivity numerical experiments for the simulation of a split Hopkinson pressure bar (SHPB) test for weathered granite samples using different combinations of model parameters. We validate the obtained results against SHPB experimental data. The experiments show that the model is mostly sensitive to parameters related to tensile and shear strengths, even in the presence of other parameter perturbations. The results suggest that the specification of tensile and shear strengths at the interfaces dominate the stress‐time history of the FDEM simulation of SHPB test.