Computation of energy release rates for kinking cracks based on virtual crack closure technique

A numerical method based on the virtual crack closure technique (VCCT) [Rybicki and Kanninen (1977)] and in conjunction with the finite element (FE) method is presented to compute strain energy release rates for cracks that kink. The method partitions the strain energy release rate and provides an efficient means to compute values of the mode I (G(I)) and mode II (G(II)) energy release rate at the tip of a kinking crack. The solution procedure is shown to be computationally efficient and operationally simple, involving only the nodal forces and displacements near the crack tip. Example problems with kinking cracks in a homogeneous material, and a layered two constituent material are presented to illustrate the current approach.