Numerical Simulation Of Temperature Field And Stress Field Of Penetration Assembly Multi-pass Welding

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.Based on summing up other's experience, this paper researcher systemically discusses the theories of temperature field and stress field of welding process and sums up the process of numerical simulation of welding based on finite element analysis software ANSYS. In this paper, a three-dimensional finite element numerical simulation on a representative penetration assembly multi-pass welding with girth welds is carried out, and then the welding temperature field and stress field of the structure are obtained. The simulated results show mostly conformity compared with the theory results and other's analysis results, which provides instruction to the numerical simulation of welding process on similar component later.The main contents of the paper are as following: the appropriate finite element model is founded; a double ellipsoid heat source model is chosen, and a mathematic model of transient process in welding is established to simulate the moving along girth welds of the heat source; the "birth and death" element method is applied to simulate the gradual "growth" of welding pass metal; the effects of heat source parameters and welding speed on temperature field are discussed; the real-time dynamic simulation of the stress produced in welding process is carried out based on the simulated temperature field results.To simulate the temperature field and stress field of multi-pass welding with girth welds based on finite element analysis software ANSYS, APDL (ANSYS Parametric Design Language) program is compiled. It is easy to optimize the welding technology and parameters using APDL program with changing corresponding parameters, which provides theory foundation and instruction on optimizing the welding technology and parameters.A feasible three-dimensional dynamic simulation method of temperature field and stress field of multi-pass welding with girth welds is established in this paper, which provides theory foundation and instruction to simulation on three-dimensional welding temperature field and stress field of complicated component, promotes application of FEM (Finite Element Method) on welding mechanics analysis and engineering.