Numerical Simulation Research On Welding Temperature And Stress Field Base On ANSYS

Welding is a complicated physicochemical process which involves in electromagnetism, heat transferring, metal melting and freezing, phase-change welding stress and deformation and so on. In order to get high quality welding structure, these factors have to be controlled, if welding process can be simulated with computer, the best design, procedure method and optimum welding parameter can be obtained.Welding process is that parts of an area is quickly heated to high temperature and then rapidly cooled. With the heat source moving, the whole weldment's temperature sharply changes, and the material's physical property parameters also sharply change. At the same time, there is latent heat of melt and phase-change. Therefore, the analysis of welding temperature field is a typical nonlinear transient heat conduction problem. Because of non-uniform temperature distribution, at the course of welding and postweld, weldment takes on serious welding stress and deformation. Calculation of welding stress and deformation includes geometrical nonlinear problem and material nonlinear problem. Welding temperature field and stress, strain field are bi-directional couple, but the influence of stress and strain field on temperature is not so much, so many people only considers the single couple which temperature field effects on stress and strain field. Base on the bi-directional couple, this paper attempt to calculate the temperature and stress field. Based on summing up others' experience, this paper research the direct method to calculate and simulate the temperature and stress field at the same time through a board surfacing welding sample.The main contents of the paper are as following: the calculation in welding process is a material nonlinear procedure that the material properties change with the temperature;choose the function of Gauss as heat source model, use the function command to apply load of moving heat source. A mathematic model of transient thermal process in welding is established to simulate the moving of the heat source. The effects of welding speed, welding current and effective radius electric arc on temperature field are discussed. Through real-time dynamic simulation of the stress produced in welding process, the thermal stress andresidual stress in welding can be predicted by using the simulative analysis method in this paper.Through research and practical verify, this paper establishes a feasible dynamic simulation method on 3D welding temperature field, stress and deformation, which provides theory foundation and instruction, promotes the application of FEM (Finite Element Method) on welding mechanics analysis and engineering.