Cold-formed ferritic stainless steel closed built-up beams: Flexural behaviour and numerical parametric study

Abstract

Abstract The flexural behaviour of cold-formed ferritic stainless steel (CFFSS) closed built-up beam composed of lipped channel sections orientated face to face was examined numerically, using a finite element (FE) package ABAQUS. The developed FE models were first validated against the experimental data collected from the literature before performing the desired parametric study. Thirteen different sections were analysed, with varying plate slenderness, using two different material grades (EN 1.4003, EN 1.4509) with three different material properties and wall thicknesses. The simply supported built-up closed beams were analysed under four-point bending. The moment capacity of the built-up beams dropped with the increase in the compression flange’s plate slenderness. The pool of numerical strengths was used to assess the current DSM’s appropriateness, proposed DSM for cold-formed steel closed built-up beams, and proposed DSM for ferritic stainless steel hollow beams. Based on the above-stated strength comparisons, suitable modifications were proposed for the current DSM specifications, mainly targetting CFFSS closed built-up beams made of lipped channel sections (typically failing by local buckling). Lastly, a reliability analysis was performed to check the reliability of the current and proposed DSM specifications for CFFSS closed built-up beams.