Three-Dimensional Element Partition Method for Fracture Simulation

A three-dimensional (3D) element partition method for simulating fracture problems is proposed here. In this method, cracks are embedded into elements in a more straightforward manner without any nodal interpolation enrichment or any extra degrees of freedom introduced. When a crack runs across an element, the element is divided into two subbulk elements and one subsurface element. The intersection points between element edges and crack faces are taken as the virtual nodes. Thus, the displacements of the virtual nodes are the extra degrees of freedom. To eliminate these extra degrees of freedom, it is assumed that the displacements of the virtual node are related only to its adjacent nodes at the same side of the crack. The least-square interpolation technique is adopted to characterize their relationship. With this method, the cracked element deformation is related to its neighborhood. The stiffness matrix and nodal force vector are derived. The friction and contact effect between crack faces are implicitly incorporated into the numerical model through the subsurface element. With the 3D element partition method, the crack is allowed to embed into an element without mesh modification or remeshing, which makes the fracture simulation highly efficient. (C) 2015 American Society of Civil Engineers.