Study on the Generation and Redistribution Mechanism of Residual Stress in Bilateral Rolling Correction Process for Thin-Walled Parts

The distortion and dimensional instability are the main problems in the machining of thin-walled parts with high-strength aluminum alloys. To ensure the accuracy of aircraft assembly, distortion correction process is essential. Bilateral rolling process has been widely used to correct the distorted parts in the aerospace industries due to the introduction of proper plastic deformation and residual stresses. However, the generation and redistribution mechanism of residual stresses in bilateral rolling correction process remains unclear. This internal mechanism was investigated by finite element method (FEM) in this paper. First, FE models were verified by experiments in terms of residual stresses and strain. Then, simulation results (e.g. plastic strain, true strain and part distortion) were extracted for further analysis. It was shown that the residual stresses are produced in the compatibility process of plastic and elastic strain, and a large plastic deformation can lead to a high amplitude residual stresses. Besides, the binding force from the surrounding materials also results in higher strain gradient and amplitude of residual stresses. Although part distortion has little effect on the limit value of residual stresses, it greatly influences the redistribution of the residual stresses.