Stress intensity factors of a crack emanating from a cold expanded hole: Effects of edge distance ratio

摘要

Cold expansion method has beneficial effects on extending the fatigue life of structures containing holes. However, for holes located near the plate edge, there is concern about the residual stress distribution around the hole that associated with beneficial effect of cold expansion process. The purpose of this study is to investigate the influence of edge distance ratio (EDR) on the stress intensity factors of a crack emanating from a cold expanded hole, where EDR is edge distance/hole diameter (or e/D). A 2-D finite element simulation was carried out with various degrees of cold expansion and various EDRs. It was found that the reduction of EDR below e/D=3 has significant effect on the tangential compressive residual stress zone. Furthermore, for a crack considered in the ligament, a significant reduction in the stress intensity factors was found in a cold expanded hole for both small and large EDRs.