3d finite element simulation of t-joint fillet weld: effect of various welding sequnces on the residual stresses and distortions

TL;DR: In this paper, the authors extended the previous work of Teng et al. and focused on numerical simulation of welding sequence effect on temperature distribution, residual stresses and distortions of T-joint fillet welds.

Abstract: Due to the nature of welding process involving localized heat generation from moving heat source (s), rapid heating in the welded structures, and subsequent rapid cooling, problems such as residual stresses and distortions of welded structures remain great challenges to welding practitioners, designers and modeler. From modeling point of view, it will be very useful if the parameters of interest which contribute to the residual stresses and distortions in various types of welded joint and structure application can be simulated numerically so that welding performance with respect to the various aspects could be assessed and evaluated in an efficient manner (Goldak & Akhlagi, 2005; Lindgren, 2006; and Zacharia et al., 1995). Thorough consideration and assessment of the welding quality could then also be performed in earlier stage in a virtual environment. Moreover, dimensional inaccuracies due to the welding deformation giving rise problems in subsequent assembly and fabrication processes could also be predicted along with the necessary justification needed. In recent years, various aspects and interests in the numerical modeling of welding residual stresses and distortions, mostly using finite element method, have been elaborated by researchers. Teng & Lin (1998) predicted the residual stresses during one-pass arc welding in steel plate using ANSYS software and discussed the effects of travel speed, specimen size, external mechanical constraints and preheating on the residual stresses. Tsai et al. (1999) studied the distortion mechanisms and the effect of welding sequence on panel distortion and utilized 2D finite element model. Residual stresses and distortions in T-joint fillet welds with the effects of flange thickness, welding penetration depth and restraint condition of welding was simulated by Teng et al. (2001) using thermal elasto-plastic finite element techniques. Further, effect of welding sequences on residual stresses of multi-pass butt-welds and circular patch welds was also investigated by Teng et al. (2003). Moreover, Chang & Lee (2009) performed the finite element analysis of the residual stresses in T-joint fillet welds made of similar and dissimilar steels. The present study extends the previous work of Teng et al. (2001) and focuses on numerical simulation of welding sequence effect on temperature distribution, residual stresses and distortions of T-joint fillet welds. Several welding sequences were considered and the resulted distribution of welding temperature, longitudinal and transverse residual stresses and angular distortions were simulated utilizing three dimensional finite element models. Four welding sequences considered were one direction welding, contrary direction welding, welding from centre of one side and welding from centres of two sides. Further, a welding sequence producing the smallest residual stress, distortion as well as distortion difference between both flanges was then investigated. The numerical simulation was done in ANSYS environment.