Research On Residual State Of FSW-T On Rail Vehicle Structure

With the rapid development of rail transportation industry,the demand for rail vehicle aluminum alloy profiles is also increasing.T-joint was the very common form of profile welding,and widely used in important welded structures such as rail vehicles,ships,marine engineering,and aerospace engineering.As,compared with plate butt welding components,the temperature distribution and stress strain distribution are much more complex.At present,there are relatively few numerical simulation studies about T-joint,but in practical,the welding quality of the T-joint is required to be very high.Therefore,it is necessary to conduct in-depth research on the numerical simulation of this aspect.In this paper,for the T-joint,the finite element software ABAQUS is used to numerically simulate friction stir T-joint.First of all,for the T-joint of AL2024 aluminum alloy material,the temperature distribution was analyzed and compared with the temperature distribution of the butt welding plate.The influence of the welding speed and rotation speed on the T-joint temperature distribution was discussed.The sequential thermo-mechanical coupling method was used to study the residual stress and residual distortion of the T-joint the main plate and stringers and the effect of different material models on the T-joint welding residual stress and residual distortion.Secondly,The finite element models of different T-shaped structures were established from three aspects of the length,thickness and shape of the stringers and was simulated the temperature distribution,residual stress distribution and residual distortion.The influence of the T-shaped structure on the residual stress and residual distortion was analyzed.Meanwhile,the residual stress and residual distortion was simulated after heat treatment.And the effect of post weld heat treatment on the residual stress and residual distortion of T-joint was analyzed.Finally,for the 6082-T6 aluminum alloy,which is a common material on rail vehicles,the Johnson-Cook material model was used to the residual stress and residual distortion and analyzed the effect of the length of the stringers and the post-weld heat treatment on the T-joint the residual stress and residual distortion.This article is for friction stir T-joint,the influences of the stringers geometry,post weld heat treatment and different material models on the residual stress and residual distortion of T-joint were studied,providing a theoretical reference for practical engineering problems.