A phase field modeling of dynamic brittle fracture at finite strains

摘要

In this paper, we review and implement the phase field model for dynamic brittle fracture at finite strains. This model approximates sharp crack discontinuities using a continuous scalar field, the so-called phase field, which represents the smooth transition between the intact and broken material phases. Furthermore, an original length-scale parameter governs the diffusive approximation of sharp cracks, while the evolution of the phase field describes the fracture process. We account for the loss of the material stiffness during fracture by linking the phase field to the body's bulk energy using a quadratic degradation function. A volumetric-deviatoric split is applied to distinguish the fracture behavior in tension, shear, and compression. The phase field model is implemented within the in-house finite element software SESKA. Herein, the phase field and displacement are computed simultaneously using the Newmark time integration. We demonstrate the capabilities of the model by solving a single-edge notched block under tension and shear. Additionally, we investigate the effect of the length-scale parameter and mesh-size dependency on the solutions.