A thermodynamically consistent phase field model for mixed-mode fracture in rock-like materials

A thermodynamically consistent phase field model with new crack driving forces is proposed to simulate the mixed-mode fracture phenomena in rock-like materials. The governing equations are derived using the volumetric and deviatoric strain split. Based on the Benzeggagh-Kenane failure criterion, our model captures the salient features of different fracture modes, e.g., pure tensile dominated fracture, pure shear dominated fracture, and mixed tensile-shear fracture and mixed compressive-shear fracture phenomena. The fully monolithic algorithm enables our new phase field model to obtain stable numerical results with fast numerical convergence. The three-point bending test of concrete beam is considered for validation. The numerical results are collaborated by test results from the literature. Afterwards, the numerical model is applied to study crack propagation and coalescence in rock-like specimens under uniaxial compression. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).