Out-of-plane welding distortion prediction and mitigation in stiffened welded structures

Abstract

A holistic investigation on out-of-plane welding distortion in fabrication of several stiffened welded structures with considering prediction and mitigation is presented. Experiments of typical fillet welded joints and its assembled stiffened welded structures are conducted first, and out-of-plane welding distortion is systematically measured. Different welding distortion patterns, so-called bending distortion and welding buckling, are obviously obtained from the measurements of the examined parallel and cross stiffened welded structures, respectively. A combined computational approach, which involves thermal elastic plastic (TEP) finite element (FE) analysis, eigenvalue analysis, and elastic FE analysis, is then employed to predict the out-of-plane welding distortion and clarify the generation mechanism for different welding distortion patterns. In particular, eigenvalue analysis can support the critical condition for welding buckling occurrence. Since the bending and welding buckling are caused by different reasons, the mitigation processes with flame heating are carried out individually. In detail, line heating is implemented in the opposite side of welded joint to produce inverse bending, and spot heating is employed to heat the region far away from welding line to eliminate effect of inherent deformation on welding buckling generation.