Studies of Residual Stress in Single-Row Countersunk Riveted Lap Joints

Abstract

Variations of stress and strain, from the riveting process through the tensile loading stage in lap joints with a single countersunk rivet, were studied experimentally and numerically. In situ microstrain gauges were used to measure the strain variations during the entire loading sequence. Three-dimensional finite element (FE) models were generated to simulate the experimental setup. The material elastoplastic constitutive relationship and geometric nonlinear properties, as well as nonlinear contact boundary conditions, were included in the numerical simulations. The numerical modeling techniques were validated using the experimental data. The residual minimum principal stress resulting from the riveting process and the maximum principal stress when the joints were in tension, determined from the FE analyses, are presented. The stress variations along a prescribed path are also presented. The aim of the research is to develop an accurate three-dimensional numerical technique to study the residual stress and strain as well as the stress and strain variations that occur during the entire loading history.