High-strain-rate fracture behavior of rock-like materials: Insights from Split Hopkinson Pressure Bar testing and dynamic phase-field modeling

This study integrates a hydrostatic-spectral-deviatoric decomposition within a dynamic phase-field finite element framework to assess its effectiveness in simulating fracture patterns in brittle materials subjected to high strain-rate compressive loading. The investigation focuses on Split Hopkinson Pressure Bar (SHPB) experiments using gypsum plaster specimens with central holes, tested in a synchronously assembled setup. The hydrostatic-spectral-deviatoric decomposition enables a distinction between tensile and compressive strain energy components to accurately model dynamic fracture processes in quasi-brittle materials under compressive and mixed-mode loading, where traditional formulations often fall short. To maintain consistency, the numerical simulations were calibrated using material parameters previously identified through quasi-static tests on the same material and different geometries. The simulated results closely mirrored experimental observations, successfully reproducing key features such as crack paths, propagation sequence, timing, boundary motion, and crack tip velocity. This enhanced modeling approach offers valuable insight into dynamic fracture behavior in brittle systems and underscores its potential for improving predictive capabilities under high strain-rate loading scenarios. • A decomposition method for dynamic phase-field fracture is presented. • Crack evolution is validated by high-speed X-ray SHPB experiments. • The method captures tensile-driven cracks under compressive dynamic loading. • Crack tip speed and sequence match experimental high-strain-rate results. • Model improves accuracy in mixed-mode brittle fracture under impact.