Crack growth simulation for arbitrarily shaped cracks based on the virtual crack closure technique

In this paper, crack growth simulation for arbitrarily shaped cracks was investigated based on the virtual crack closure technique. During simulations, the crack front was represented by an approximated zigzag line which had the same general shape as the given crack. For this approximated zigzag crack front, a modified approach was developed to determine the required nodal forces, virtually closed area and displacement opening. After the strain energy release rate G was calculated, crack growth was governed by the fracture criterion G/GC = 1 at all the crack tip nodes. The important features of the proposed approach are that (i) a simple stationary finite element mesh can be used for arbitrarily shaped cracks and (ii) adaptive re-meshing technique is avoided in studying crack growth. Three cases having different initial crack shapes are presented to assess the validity of this approach and to evaluate the ease of use in tracking crack growth. Reasonable agreement between the present study and other approaches are obtained. The shape changes during crack propagation can also be tracked with ease.