Numerical Simulation Of Welding Temperature Field And Stress Field Of T-joint

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.This paper focuses on numerical simulation of T-joint welding in welding in welding temperature field stress and deformation by finite dement software ANSYS based on the theory of thermal elastic-plastic .The welding temperature at any time is obtained .The stress during welding and the residual stress are obtained . Following contents are included in this paper:1. Three-dimensioned model of T-joint is developed to simulate welding temperature field, stress and deformation . In order to solve the problem and improve solution accuracy, this paper chooses suitable material property parameter , uses transition mesh to ensure it has a fine grid in the welding zone and chooses suitable time step .It uses the method of“birth and death”method to simulate temperature field in the moving heat source.2. Welding temperature field and stress, strain field are bi-directional couple, but the influence of stress and strain field on temperature is little and the calculating ability of computer is limited ,so this paper only considers the single couple which temperature field effects on stress and strain field and save the result , then use the temperature result as load to calculate welding stress and deformation . Then, the temperature field were introduced to do elastic analysis.3. The calculation results of temperature field : Analyze several key thermal cycling curve accords with the welding process temperature variation, the maximum temperature of butt weld joints reached 2020 degrees. The maximum temperature of T-joint reached 1994 degrees. Analyze the welding temperature field at different time. The welding temperature field is basically accord with theoretical results. 4. The calculation results of stress field : Analyze the residual stress on the weld seam center line and vertical each node of the residual stress changes of butt weld joints, the maximum residual stress reached 203MPa.Stress changes is analyzed at different time T-joint along different paths, the maximum stress direction along the weld is 213MPa.The maximum tensile stress direction is 209MPa along the direction perpendicular to the welding center. Along with increasing the distance from weld line, the tensile stress decreased gradually and translated into compressive stress, the maximum compressive stress reached 107MPa.