Welding Residual Stress Analysis and Its Influence Study on Warm Rotor of an HTS Motor

The welding residual stress and its influence on the warm rotor of an HTS motor was analyzed in this study. First, the thermo-elastoplastic FEA and the heat source model were introduced. Second, the influences of weldpass number, welding current, and groove types on the welding residual stress of the T-joint were analyzed. Then, the T-joint sample was manufactured and the residual stress was tested by the X-ray diffraction to verify the correctness of the FEA method. Last, the dynamic performance of the shaft was analyzed by the co-simulation analysis of welding and vibration. The results showed that the welding residual stress decreased with the increase in the number of weld passes and welding current had little effect on that. Compared with the V-shaped groove, the K-shaped groove and J-shaped groove were more suitable for the T-joint. Besides, the residual stress was superimposed with the stress caused by the working load and then weakened the strength of the T-joint. Moreover, the dynamic performance of the shaft was analyzed by the co-simulation analysis of welding and vibration. The relative error of the first three-order natural frequencies with residual stress and without that was less than 3.5%, which indicates that the residual stress had little effect and can be ignored.