Boundary element analysis of cracks

This paper presents a boundary element formulation that can be used for traction free or pressurized central, edge or branch cracks. The problems associated with the evaluation of integrals containing higher order singularities, which have forced many researchers to modify the boundary integral equations, are overcome in this paper. This permits the use of traction boundary conditions with no modification or addition to the number of unknowns. Comparison of results for conforming and1 non-conforming elements in modeling of cracks reveals that the oscillation in stresses near the crack tip for non-conforming elements used in the past makes the stress intensity factor dependent on the points used in its calculation. Stress intensity factors are calculated using three different methods. Numerical results for central, edge and branch cracks validate the ideas presented in this paper.