Based on 10 previously conducted axial compression tests on stainless-clad bimetallic steel (SCBS) welded box-section columns, precise finite element (FE) models incorporating actual geometric imperfections and residual stress distributions were developed in Abaqus. Comparisons among models using various element types indicated that single- and double-shell models produced similar levels of accuracy. Using the validated FE models, a comprehensive parametric study was performed, involving a total of 2,970 models. The effects of initial geometric imperfections, welding residual stresses, composite ratios, and base material strength grades were systematically investigated. For long columns, initial local imperfections had a minor influence on stability, whereas welding residual stresses had a significant effect that cannot be neglected. The global stability coefficient of the columns decreased as the composite ratio increased. Finally, by combining the experimental data and FE results, the calculation methods in existing stainless steel and carbon steel design codes were evaluated. The results indicate that current code provisions cannot be directly applied to predict the flexural buckling capacity of SCBS columns with varying composite ratios. Accordingly, a new design formula for the flexural buckling capacity of axially compressed SCBS columns was proposed, based on the Perry formula, and tailored to account for different composite ratios.
Wu et al. (Sun,) studied this question.