Simulation Of The Welding Residual Stress Effection Fatigue Life Of7A52Aluminum

7A52super-hard alloys are lightweight materials commonly used in military weldedstructures. In this paper, with the aluminum alloy welded joints of double wire MIGwelding as the research object, a finite element simulation of welding residual stress effectson fatigue properties were carried out using the finite element software ABAQUS andfatigue analysis software MSC.fatigue. This process is mainly composed of three parts:welding temperature field, stress field and residual fatigue life analysis. For more accuratestudy of welding residual stress effects on fatigue properties, the environmental,metallurgical, surface processing status and so on factors are excluded. The correspondingcontrol group connectors in this paper were established and the numerical simulation andrelated comparative analysis were carried out. The main results and conclusions obtainedare as follows:Using the unit "life and death" and the unit "tracking" method and considering relatedthermal physical properties of the material parameters and temperature nonlinear, thedynamic weld filled process of7A52aluminum double wire MIG welding process wascompleted and the welding temperature field was obtained by ABAQUS finite elementsoftware. Meanwhile, the instantaneous stress field of the7A52aluminum double wireMIG welding process and longitudinal and transverse residual stress cloud after weldingwere simulated by using the sequentially coupled thermal stress method. The performancesof its longitudinal stress distribution along the vertical direction of the weld zone aretensile stress at center, compressive stress on both sides and a bimodal distribution is veryobvious; Results of transverse residual stress is the compressive stress distribution on bothends of the weld and tensile stress at the center and, the maximum tensile stress is105.8MPa, while the maximum compressive stress value is215.3MPa about2times themaximum tensile stress.By using the MSC.fatigue analysis software and100MPa maximum tensile stressspectrum as example, the fatigue lives of the welded joints of the double wire MIGwelding of7A52aluminum alloy and control group connectors were successfullysimulated. The common denominator is the fatigue dangerous parts of welded joints are alllocated around the central seam weld toes providing a reliable theoretical basis to eliminate residual stresses. The difference is that the obtained fatigue life of7A52aluminum doublewire MIG welded joints is much less than that of the control group connectors. Theanalysis found that, after receiving the work load, the joint will generate residual stressrelaxation behavior. Therefore, by using the static load case to compensate for residualstress and re-analyzing the welded joints fatigue life under the situation of welding residualstress relaxation,, the obtained joint fatigue life is basically the same with the controlgroup. It shows that residual stress in the characteristic of relaxation has less effect onwelded joints fatigue life.