Computer simulation of fatigue crack growth under different loading conditions using Boundary Cracklet Method (BCM)

In this study, fatigue crack growth in an infinite plate having two holes separated at some distance with crack emanating from one hole and propagating toward other hole is analyzed by using two-dimensional Boundary Cracklet Method (BCM). A comparative study is done with three different cases of far-field loading i.e. uniform stress along X-direction, uniform stress along Y-direction and shear loading. Stress intensity factors and fatigue life are calculated in each case and compared with each other. The fatigue crack growth is assumed to follow Paris-Erdogan Law and maximum tangential stress criteria is used to find the crack propagation path. For modelling of holes, 16-sided polygon are created as straight line refereed as 'cracklets' and in initial configuration, a crack of certain length and orientation is also modelled in the form of line at one of the holes. The results and conclusions are drawn based on the plots and figures. Model is also validated with two fatigue crack growth problems presented in literature and a good agreement between the results is obtained. The effect of number of sides of polygon (used to model the holes) on accuracy of BCM is also studied.