Research Of Welding Residual Stresses And Distortion For T-joint By Using Finite Element Analysis

T-joint fillet welds are extensively used in ship building engineering and bridge structures. It is well known that stress concentration in welded joints shortens the life span and introduces dimensional instability of welded structures. Localized heating from the welding process and subsequent rapid cooling induces tensile residual stress near the toe of the T-joint in the fillet welds. Welding produces thermal stresses that cause structural distortions, which influence buckling strength of the welded structures. However, numerical finite element methods are capable of consistently capturing the induced residual stresses and deformation caused by heat input to the weld.A working welding model was created using a commercial finite element software package with the capabilities to model welding process. A three dimensional full physics process model was systematically developed.This study describes the thermal elastoplastic analysis using the finite element simulation performed by MSC.Marc software to analyze the transient nonlinear thermal and coupled thermo-mechanical behavior and evaluate the residual stresses and distortions of the T-joint in fillet welds.The objective is to investigate the temperature fields during the transient welding simulation process. Develop a simulation system for thermo-mechanical welding processes taking into account the TIG welding parameters during simultaneous welding of a T-joint fillet welding of 3mm AISI 316 stainless steel plate(a single-pass welding process was considered) and investigate the possibility of minimizing the induced residual stresses by means of preheating temperature. Concave T-joint fillet weld joint structure was also modeled and the residual stress results were compared to that of the flat fillet T-joint to determine which is suitable for fatigue analysis in my future work. Furthermore, this work employs the element deactivation and activation technique for filler metal addition in the T-joint welds. Effects of increasing the welding speed and how it affects the weld pool shape were discussed.