Inverse Discontinuity Formulation of Fracture

Other conference contribution, 2005

A theoretical and computational framework for linear and non-linear fracture mechanics is presented. We use the material forces concept as a basis for the formulation, due to the close relation between on one hand the Eshelby energy-momentum tensor and on the other hand material defects like cracks and material inhomogeneities. By separating the discontinuous displacement from the continuous counterpart in line with the eXtended Finite Element Method (XFEM), we are able to formulate the weak equilibrium in two coupled problems representing the total deformation. However, in contrast to standard XFEM, where the direct motion discontinuity is used to model the crack, we rather formulate an inverse motion discontinuity to model crack development. The resulting formulation thus couples the continuous direct motion to the inverse discontinuous motion, which may used to simulate linear as well as nonlinear fracture in one and the same formulation. In fact, the linear fracture formulation can be retrieved from the non-linear cohesive zone formulation simply by confining the cohesive zone to the crack tip.