Calibration and Plastic Correction on Strain Release Coefficients in Welding Residual Stress Measurement of LY12 Aluminum Alloy by Blind-Hole Method

The calibration and correction of the strain release coefficients A and B were conducted by the combination of finite element simulation and experiments in the welding residual stress measurement of LY12 aluminum alloy sheet by the blind-hole method. By introducing the plastic additional strain, the plastic correction formula based on the relationship between the strain release coefficients and the shape-changed specific energy was obtained. In the end, the welding residual stresses of the butt welding LY12 aluminum alloy sheets were measured by the blind-hole method with the corrected strain release coefficients and the experimental results and simulation results were compared and analyzed. The results show that the maximum measurement error of the welding residual stresses reduced from 57.457% to 3.208% with the given plastic correction formula, showing the good correction effects.