Numerical Simulation And Experimental Research On Welding Residual Stress Of AH36

Welding plays an important role in the hull structure,because the high temperature and complicated welding process will cause the hull structure to produce residual stress and angular deformation that cannot be eliminated.The welding angle deformation will not only reduce the overall strength and toughness of the hull structure,but also bring greater hidden dangers to the stability and safety of the hull structure,such as causing corrosion and cracking at the weld,and it will also affect the fracture characteristics of the structure.And the fatigue strength brings unfavorable consequences.Butt welding and fillet welding of profiles are the most typical in ship welding.This paper uses ANSYS thermodynamic analysis software to simulate welding stress and deformation under different welding sequences,and compares and analyzes the welding results to obtain a more appropriate welding process plan.This thesis first conducts experimental research,based on the theory of thermo-elastoplasticity,transforms the actual welding elements into a simulation program by writing APDL language,and uses AH36 high-strength steel to realize the process of loading the heat source and the melting and joining of the profile.Based on the experimental verification of the simulation results,the temperature field and stress field under different welding sequences are analyzed,and the corresponding welding stress and angular deformation results are obtained.Through research work,the following conclusions can be drawn: in flat plate butt joints and T-shaped fillet joints,the residual stresses are concentrated at the welds,which are specifically manifested in the stresses at the butt welds of the two flat plates and at the intersection of the web and wing welds.The largest and most concentrated.Different welding sequences have little difference in the magnitude of residual stress,but they have different effects on the angular deformation of the profile.Since two welding passes are carried out,if the welding direction of the second pass is opposite to that of the first pass,there will be no overall angular deformation on the flat plate after welding,but only partial angular deformation.The degree of angular deformation of the T-joint at the weld is correspondingly reduced,and the stress value at both ends of the T-joint is also lower.Therefore,accurately simulating the influence of welding residual stress on material deformation and choosing the correct welding process to control residual stress and angular deformation have important guiding significance for ship welding engineering.