Fracture behaviour of thin-walled cold-formed steel at elevated temperatures

• Published in: Construction & building materials Vol. 429; p. 136446
• Main Authors: Rahnavard, Rohola, Craveiro, Hélder D., Simões, Rui A., Gardner, Leroy
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 24.05.2024
• Subjects: Abaqus; Cold-formed steel (CFS); Damage evolution law; Ductile damage; Elevated temperature; Engineering stress-strain curve; Finite element analysis; Post-necking behaviour; Abaqus; Elevated temperature; Damage evolution law; Ductile damage; Engineering stress-strain curve; Cold-formed steel (CFS); Finite element analysis; Post-necking behaviour
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2024.136446

Cold-formed steel (CFS) is being increasingly used in structural applications due to its high strength-to-weight ratio, ease of construction and versatility. The performance of CFS structures in fire has received signification recent attention, but the fracture behaviour of thin-walled CFS at elevated temperatures, which is fundamental to the fire response of the key components, like connections has yet to be extensively studied; this is therefore the subject of the present paper. First, using experimental data on cold-formed grade S280GD+Z275 steel at elevated temperatures from the literature, damaged true stress-strain curves considering the post-necking behaviour are determined. Then, a fracture prediction approach, implemented in the finite element analysis software Abaqus and considering ductile damage and a damage evolution law is calibrated and validated against the experimental data. Finally, the applicability of the proposed approach to different types of CFS material, including high-strength CFS, is assessed. The results show that the proposed model can accurately predict the fracture behaviour of CFS at elevated temperatures. •Description of post-necking damaged true stress-strain behaviour of cold-formed steel using weighted average method.•Proposal of empirical formula for determining suitable values for weighting factor.•FE modelling of fracture in cold-formed steel coupons at elevated temperatures.•Validation of developed FE models against existing coupon tests covering a range of grades and temperatures.