焊接残余应力对2219铝合金熔焊接头承载能力的影响

To study the specific effect of welding residual stress on the bearing capacity of 2219 aluminum alloy and its mechanism, the mechanical properties of the two welded joints were tested by comparative tests. The finite element model of welding process was established, and the residual stress distribution of standard specimen and large-sized specimen was obtained. The simulation results showed that the welding residual stress was basically released during the preparation of standard samples. The mechanical tensile and joint characterization tests of specimens with and without residual stress were carried out respectively. The test results indicated that the existence of welding residual stress has no obvious effects on the mechanical properties, fracture forms and fracture characteristics of welded joints. Based on the theory of the fracture mechanics of mesoscopic damage, the mechanism of the damage and the accumulation of the residual stress in the joint was analyzed and discussed in detail. The results revealed that the released stress after the formation of the welded joint does not affect the bearing capacity of the joint, but the additional plastic strain which caused by the residual stress control measures during and after welding, which may have an impact on the bearing capacity of the joint.