An adaptive continuous-discontinuous approach for the analysis of phase field fracture using mesh refinement and coarsening schemes and octree-based trimmed hexahedral meshes

In this paper, we present a novel adaptive continuous-discontinuous approach for the analysis of phase field fracture. An initial trimmed hexahedral (TH) mesh is created by cutting a hexahedral background grid with the boundary of the solid domain. Octree-based adaptive mesh refinement is performed on the initial TH mesh based on an energy-based criterion to accurately resolve the damage evolution along the phase field crack. Critical damage isosurfaces of the phase field are used to convert fully developed phase field cracks into discontinuous discrete cracks. Mesh coarsening is also performed along the discontinuous discrete cracks to reduce the computational cost. Three-dimensional problems of quasi-brittle fracture are investigated to verify the effectiveness and efficiency of the present adaptive continuous-discontinuous approach for the analysis of phase field fracture.