Cold-formed steel square hollow members with circular perforations subjected to torsion

This paper describes an experimental and numerical investigation on torsional behaviour of unperforated and perforated cold-formed steel hollow section members. The material characteristics and torsional performance of YSt-310 cold-formed steel square hollow section members (conforming to Indian Standard 4923), were initially studied. experimentally. Effects of size, number, and position of circular perforation on member torsional strength were investigated using validated finite element models, via Abaqus. Additionally, using the FE analysis results, design equations were proposed in Eurocode (EN), Direct Strength Method (DSM) and Deformation Based Method (DBM) formats; for unperforated square hollow section members. The approach is then extended for perforated cases, having circular single and double perforations, using suitable reduction factors, considering effects of both cross-sectional slenderness and perforation size. The proposed design equations were assessed through reliability analysis and were found to be safe for design of cold-formed square hollow sections under torsion. (C) 2019 Elsevier Ltd. All rights reserved.