On the effects of unilateral boundary conditions on the crack growth rate under cycling bending loads

Sometimes, structural components experience service conditions that have not taken into account at the design stage. In this study, the effects of the boundary conditions on the crack propagation life have been evaluated using the modified Virtual Crack Closure Technique for a surface crack existing at the root of a shoulder fillet notch in a circular stepped bar under bending. The results show that the presence of a unilateral boundary condition at the shoulder fillet notch significantly influences the SIF’s and therefore the number of cycles to failure, but the shape of the crack front does not change during propagation.