Behaviour of stainless steel press-braked channel sections under compression

Abstract

This paper describes an experimental and numerical investigation of stainless steel material response and behaviour of press-braked channel sections under pure axial compression. A material test programme that covers austenitic stainless steel EN 1.4301 was carried out to study the nonlinear stress-strain relationship and changes of basic mechanical properties due to the press-braking processes. The key experimental results were used to estimate the appropriateness of existing analytical material models and to determinate strain-hardening exponents. The validation of recently proposed models for predicting the strength enhancements in cold-formed sections was also performed. Additionally, corresponding Finite Element (FE) models were built for flat and corner coupons to match the tensile test results and to establish the parameters of a ductile damage model in Abaqus. The susceptibility to local buckling of the channel section was determined by stub column tests. The FE model, calibrated and validated against the experiments, was used to perform a parametric study over a wide range of section slenderness. This allowed the quantitative assessments of design procedures stated in Eurocode 3 and American' Specifications, and the Continuous Strength Method (CSM). The comparisons between generated data and predicted strengths reveal the conservatism of the Eurocode 3 design method for both non-slender and slender channels. In contrast, the CSM reflects significantly better the nonlinear buckling behaviour of non-slender channels. Although this method gives more accurate results comparing to effective with method employed in Eurocode 3, the slight unsafe predictions were found for slender channels in the intermediate cross-section slenderness.