Crack-tip stresses and their effect on stress intensity factor for crack propagation

In this paper, analytical and numerical simulations of the crack-tip stresses are presented. Analytical calculations are performed utilizing modified Rice and elastic equations. 2D finite element analyses (FEA) are conducted in parallel using ANSYS. Results from both methods are compared and discussed in terms of the crack-tip compressive residual stresses. Then, the effect of the compressive residual stresses is quantified in terms of the stress intensity factor for crack propagation, KPR, using ‘clamping force’ method. The comparison between the calculated KPR values and those obtained experimentally by Lang demonstrates a fairly good agreement. Both the present results and Lang data independently support a two-parameter, KmaxTH and ΔKTH, description of the threshold condition for fatigue crack propagation.