Reconstruction of Residual Stress Field in A Fricition Stir Welding Joint of Aluminium Alloy Plate Based on Eigenstrain Reconstruction Method

Based on the eigenstrain reconstruction method and limited measurements with hole-drilling method, the longitudinal residual stress distribution in a friction stir welding joint of 4 mm thickness aluminium alloy plate was reconstructed by the thermal-elastic finite element method. The effects of the order of polynomial and the amount of the experimental data on the constructed residual stress field were also investigated. The results show that the longitudinal residual stress distribution can be well reconstructed from the limited experimental data treated by interpolation fitting based on the eigenstrain reconstruction method with the order of the Chebyshev polynomial larger than 10 to construct the unknown eigenstrain. In addition, the constructed stress would be more accurate if the experimental data includes the stresses in the required regions.