Numerical Simulation And Fatigue Analysis Of Welding Residual Stress Based On T-joint Of Q550 Frame

Welding involves a complex analysis process of different physical fields.At the same time welding is an indispensable process,especially in the frame,ship,aerospace.For example,in the frame construction process,it is this complexity that causes the welding residual stress and deformation of the structure.This residual stress and deformation reduces the strength,stability and fatigue of the frame and even the overall structure,which affects The quality of the structure.The existence of welding residual stress will directly affect the strength and bearing capacity of the frame steel structure.It is very important to accurately infer the mechanical behavior and residual stress in the welding process and study the superimposed effect of residual stress and external load.In order to minimize the residual stress caused by welding in terms of structural design,this article takes the multifunctional car as the engineering background and takes the typical T-joint in the frame as the research object,and establishes the model of the T-joint in the ANSYS finite element software,Analyze the distribution law of residual stress of web and plate welding,and combine with Fe-safe software to study the trend of fatigue life of T-joint under the influence of welding residual stress.Specific work in the following areas:(1)Summarize the basic theory of finite element analysis of welding residual stress and fatigue life,introduce relevant research history and achievements at home and abroad.(2)Establish a numerical calculation model for the welding residual stress of the T-joint,determine the boundary conditions and the thermal-elastoplastic properties of the material,and solve the problem of the filling of the birth and death elements of the solder,the phase change latent heat,the loading of the convection coefficient,and the input of the heat source Key issues such as the determination of coefficients;through numerical analysis,study the temperature field distribution and stress field distribution of T-joints after welding simulation;explain the structure from the three directions along the weld,plate thickness,and perpendicular to the weld Distribution rule of welding residual stress.(3)The variation of residual stress under different web thickness and welding parameters(voltage and current)is analyzed.(4)Under the effect of welding residual stress of T-joint,calculate and compare the change of fatigue life of T-joint in the presence of residual stress and neglecting residual stress;The changing trend of safety factor.