The Numerical Simulation Of Thick-plate Multi-pass Welding

Thick-plate multi-pass welding is widely used in complex structure. The welding residual stress and deformation are inevitably produced in the welding process because of the welding heat cycle. To provide the theoretical basis for preventing, controlling and regulating the welding stresses, the numerical simulation of the temperature field and the thermal stress field are very important in both academic research and practice.Take the butting joint of flat plate for example, the temperature field and stress field of the thick-plate multi-pass welding are simulated using the finite element software ANSYS.Geometry model of the butt joint is built firstly. The geometry model for three-layer and six-pass welding is selected according to the process of welding. Different meshing principles are proposed to ensure higher efficiency with various aspects concerned.As to the analysis of temperature fields, Gaussian heat source, as the moving heat source of welding, is used to simulate the welding heat cycle. The course of stuffing, melting, solidifying of metal in welding seam is simulated successfully with the birth-death element method, and the analysis result approximate to the actual fact is obtained. With the APDL parametric language, the process of solution is predigested. The heat fields of different welding parameters are simulated, which is convenient to choosing processing parameters rationally and directing the production. Also the temperature field is measured with the Thermal CAMTMS65. It is shown that the simulation results are in good accordance with the practical experiment.As to the analysis of stress fields, on the basis of the thermal elastic dynamics, welding structure model is founded by coupling the temperature field and the stress field. The distributions of residual stresses are calculated.