Residual Stress Prediction And Application Based On MARC

Computer numerical simulation technology has widely used in the welding field. Temperature filed and welding residual stress field distribution was calculated based on computer numerical simulation. It is useful to optimized welded process, Then the high quality of weld structure was obtained.The best processes,welding parameter selection,control and elimination of welding residual stress can be completed by computer instead of substantial experimental work in workshop or laboratoty.It has great economic benefits by greatly saving manpower,material and time.Based on finite element analysis software MARC,a three-dimensional finite element numerical simulation on multi-pass welding with medium and heavy plate structure is carried out. According to the antual situation of welding, selected different weld heat source,and the "birth and death" element method is applied to simulate the gradual "growth" of weld metal.,and then the stress field is obtained. The combined welding heat source which combined Gaussian face heat source with double ellipsoidal body heat source was used in weld simulation. Comparison simulation results with measured results,The residual stress field of simulation using the combined welding heat source consists with test value more exactly than using the other two heat souce.Based on finite element analysis software MARC,a three-dimentional finite element numerical simulation on multi-pass welding with pipe-plate strcture is carried out,and then the stress field is obtained.The effect of welding technology on the residual stress is investigated in this paper. The welding technology includes the welding sequence,the size of weld bead (big or small),melting repair treatmentand and ultrasonic impact treatment.The results show that the best welding technology applying a double ellipsoid heat source modal for pipe-plate strcture are big weld bead,alternative welding sequence,melting repair treatment and ultrasonic impact treatment.