Dynamic fractures in rock-like materials analyzed by high-speed photography and a dynamic phase-field finite element model

A so-called hydrostatic-spectral-deviatoric decomposition is integrated into dynamic phase-field finite element models to study its effectiveness in the prediction of crack paths and crack tip velocities in brittle materials under dynamic mixed-mode compressive loading conditions. The study focuses on dynamic experiments, including drop tower tests conducted using gypsum plaster specimens with embedded flaws and holes. The hydrostatic-spectral-deviatoric decomposition method enables a split in tensile and compressive strain energy density contributions, crucial for capturing the complex fracture behavior in brittle materials under compressive loads that traditional models struggle to simulate effectively. Numerical simulations were conducted in parallel with experiments, utilizing a unified set of material parameters derived from prior work on the same material under quasi-static conditions. This approach ensured consistency between the dynamic and quasi-static cases. Numerical results demonstrated a good level of agreement with experiments, replicating key aspects of fracture evolution, including initiation and propagation of primary and secondary cracks as well as the temporal progression of crack tip velocities. This enhanced modeling approach offers a deeper understanding of dynamic fracture mechanisms in brittle materials and demonstrates its potential for advancing fracture simulations in applications involving dynamic, mixed-mode loading scenarios. • A dynamic phase-field model using hydrostatic-spectral-deviatoric split is employed. • Experimental validation is done using drop tower tests on gypsum plaster samples. • FE simulations are done using a unified set of material parameters. • The model predicts crack paths and tip velocity under dynamic mixed-mode loading.