Comparative Evaluation of Shear-Theory-Based Welding Design Equations and Finite Element Analysis for Typical Welded Joints
Abstract
In various industrial fields such as mechanical, civil, and shipbuilding engineering, welded structures are designed based on established national standards. While these design formulas are generally reliable, especially for butt and parallel fillet welds, several studies have shown that those for fillet welds under transverse loads tend to conservatively overestimate throat stresses. To prevent misestimation of weld stresses and improve design efficiency, it is necessary to systematically analyze the strengths and limitations of existing design equations and to explore ways to complement them through FEM analyses according to weld type and key dimensional parameters. In this study, three representative welded joints—T, butt, and lap—made of SS400 steel were analyzed using FEM and compared with the Japanese shear-theory-based design equations. The T-joint showed lower average shear stress but higher peak stress due to bending effects; the butt joint exhibited close agreement (within 3%), while the lap joint showed pronounced bending deformation depending on plate geometry. The present findings confirm the validity of this shear-theory-based approach for simple geometries but also reveal its limitations under combined bending and shear conditions. Even the shear-theory-based approach of JSME also need to incorporate FEM-supported correction factors and geometry-sensitive criteria into its design standards for enhancing both the accuracy and reliability of welded joint design. This study highlights the need for further evaluation of various weld configurations defined in design standards. Reassessing the accuracy and applicability of existing design equations, considering normal, shear, and combined stresses, will help prevent misestimation and support refinement of future welding design standards.