Stress magnification factor for angular misalignment between plates with welding-induced curvature

Abstract

The construction of lightweight structures poses new design challenges as a result of the different mechanics of deformation experienced by thinner-plated structures. Because of a reduced bending stiffness, thin plates are particularly sensitive to welding-induced distortions, which include a curvature, in addition to the axial and global angular misalignment observed on thick plates. The curvature shape and amplitude determine a local angular misalignment at the welded joint, which causes non-negligible secondary bending effects. Therefore, the commonly used stress magnification factors k m solution for flat plates need a further development to include the curvature effect. This study proposes new analytical formulations, which extend the applicability of the existing solutions to the assessment of the structural stress of a curved thin plate under an axial load. The improved formulations are consistent with the geometrical non-linear finite element analysis under compression (up to ∼ 80% of the buckling limit) and tension (up to the yield strength). A sensitivity analysis is presented in order to show the dominant role of the curvature effect in the estimation of the k m factor. Regardless of the load applied, the presence of the curvature causes a flat plate solution inaccuracy greater than 10% when the local angular misalignment is more than 1.25 times higher than the global angular misalignment in the case of a thin and slender structure.

A Stress Magnification Factor for Plates With Welding-Induced Curvatures

“…This paper extends the analytical approach introduced in [12] to non-ideal slope BCs at the beam ends. This novel study utilizes the definition of fixity factors to include the rotational stiffness of the joints, see also [13] and [14].…”

“…Modelling of the initial curvature As in [12], the welding-induced distortion geometry is modelled by the superimposition of a half-sine curvature (HSC) and a linear lateral sway, thus including both a local and a global angular misalignment. This geometry, shown in Figure 5, is indicated as HSC model and expressed as:…”

“…These studies have shown valid geometrically non-linear analysis approaches for the structural stress problem, but their engineering use is challenged by the complexity of the analytical formulations. Thus, Mancini et al [12] have recently developed a more compact solution. The study considers a non-linear beam theory, which utilizes the von Kármán kinematic assumption.…”