Finite Element Modelling and Design of Cold-Formed Stainless Steel Sections (No. R845)

Abstract

This report describes the numerical investigation of cold-formed, thin-walled stainless steel sections subject to distortional buckling under compression. Austenitic alloy 304 and ferritic alloys 430 and 3Cr12 were considered. A finite element model calibrated to the data gathered in a recent experimental programme (Lecce and Rasmussen 2005) shows that material anisotropy can be ignored and that an accurate calibration model can be achieved provided nonlinear yielding and enhanced corner properties are included in the model. FE analyses of more than 570 simple lipped and lipped channels with intermediate stiffeners covering a distortional buckling slenderness range 0.47 ≤ λd ≤ 3.64 reveal that enhanced corner properties may become significant for stocky sections with a large corner area (λd <1 with a corner area of at least 10%). The experimental and FE test data were used to evaluate the Australian, North American and European codes for stainless steel and cold-formed carbon steel. The evaluation reveals that both the effective width area approach and direct strength methods are generally inadequate for the design of stainless steel sections. Modified resistance factors are recommended for the effective width approach of current design codes to meet limit states design criteria. Direct strength design curves are developed for austenitic and ferritic stainless steel alloys.