Search

Welded T-joints are commonly used in manufacturing of stiffened panels or crossbeams. However, welding of web-to-flange joint induces residual stresses and distortions resulting in significant challenges during both manufacturing and service. These issues can ultimately impact the structural performance, including fatigue and stability, and lifetime of the weldment. The purpose of current paper is determining the distribution and magnitude of manufacturing-induced longitudinal residual stresses in welded T-joints. Influence of hot rolling, thermal cutting, prestressing, welding, etc. are all included using the so-called contour method. Deformed surfaces are measured using coordinate measuring machine after wire electrical discharge machining of specimens. An inverse linear elastic finite element analysis is carried out for assessing residual stresses after data smoothing. Two-dimensional longitudinal residual stress patterns are evaluated in representative cross-sections clearly indicating high stress peaks near the welds, even exceeding yield strength of the base material. In addition, longitudinal membrane residual stresses are determined based on through-thickness stresses. In addition, a simplified residual stress model, satisfying the requirement for equilibrium of internal forces and bending moments, is developed for welded T-joints with double-sided fillet welds based on contour method results. [Display omitted] • A novel application of contour method is used for determining residual stresses. • Longitudinal residual stresses are assessed in welded T-joints. • Tensile residual stress peaks near the welds exceed yield strength of the material. • A simplified residual stress model is developed for welded structural steel T-joints. • Residual stress model satisfies equilibrium of internal forces and bending moments. [ABSTRACT FROM AUTHOR]

Repair welding for recovery from local damage of a rail head surface is known to cause high residual stress and can accelerate fatigue in the rail. This study examines repair-welded rails by applying experimental and numerical approaches. In the former approach, two newly manufactured rail specimens and four repair-welded rail specimens with two different weld depths were prepared, and their residual stresses were measured with a sectioning method. In the latter approach, a finite element repair welding simulation model was developed that adopted a prescribed temperature method with a moving block as an input heat source, and the thermal strain caused by the volume change due to solid-state phase transformation was considered. Overall, the residual stresses correlated well between the experimental and numerical approaches. The measured high compressive residual stress of −290 MPa seems to be beneficial to prevent a crack initiation in the rail surface. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigated the bending strength of girth-welded stainless steel circular hollow sections by numerical method. At first, finite element simulation of girth welding process was carried out to obtain the weld-induced residual stresses and deformations employing sequentially coupled three-dimensional thermo-mechanical finite element formulation. Then, nonlinear finite element analysis in which the moment versus end-rotation response, the ultimate moment resistance and the failure mode of the girth-welded circular hollow sections under pure bending were explored incorporating the residual stresses and depressions along with the initial global geometric imperfections was performed. Feasibility of adopting the current codified provisions (Eurocode 3) for stainless steel circular hollow sections in bending as the cross-section slenderness limit for girth-welded stainless steel circular hollow section flexural members was also examined. Results showed that the flexural behavior of girth-welded stainless steel circular hollow sections always involves local buckling near the girth weld on the compression side, which significantly affects the moment versus end-rotation behavior. Moreover, the results demonstrated that the Class 3 slenderness limit of 280 from Eurocode 3 for stainless steel circular hollow sections in flexure may be applied to girth-welded stainless steel circular hollow sections subjected to bending. [Copyright &y& Elsevier]