Variable material property method in the analysis of cold-worked fastener holes

Abstract Based on a general axisymmetric method of elastic-plastic analysis presented by Jahed and Dubey, elastic-plastic boundaries and residual stress fields induced by cold expansion of fastener holes is predicted. The method uses a linear elastic solution to construct an elastic-plastic solution. The material parameters are treated as field variables and their spatial distributions are obtained as part of the solution. This method uses the actual loading-unloading behaviour of the material and therefore is capable of predicting an accurate residual stress field. Results obtained here are compared with available experimental and finite element results. The agreement of the results with experimental measurements is very good. It is shown that employment of the actual unloading material curve can make a significant change in residual field prediction.