XFEM and EFG Cohesive Fracture Analysis for Brittle and Semi-Brittle Materials

The finite element analysis of dynamic fracture in solids and structures is challenging due to the modeling of arbitrary crack growth in the continuum domain. The well-known mesh size and mesh orientation dependences add more difficulties into the analysis of this type of problems. In this presentation, we are going to introduce two numerical methods in modeling the dynamic fracture in brittle materials for solid and structures in LS-DYNA®. Both methods were developed by Belytschko and his group [1, 14] and were based on a strong discontinuity approach combined with cohesive forces for the crack initiation and propagation. In EFG method, a visibility method is utilized to define the cracks in the solids and a fast transformation method [18] is applied to handle the boundary conditions in the cracked media. The XFEM method is implemented to model the dynamic fracture in structures. The XFEM method can be viewed as a combination of level sets method and partition of unity method [15] in the description of cracks.