6.6. Crack Propagation Criterion
6.6.1. Stress Intensity Factor Computation
The calculation of the stress intensity factors (SIFs) is based on the work of Nikishkov and Atluri (1987), who proposed an equivalent domain integral method for calculating the fracture parameter SIF of a 3D arbitrary crack. This method has been widely used in standard FEM and in this subsection it has been introduced into the CB shell element of X-FEM.
A local coordinate system (x1, x2, x3) is established at the crack tip as illustrated in Figure 6.17, where x1 is located on the crack surface perpendicular to the crack ...