Structural performance of CHS X‐joints fabricated from high‐strength steel

Abstract

Representative steel design standards have limited the use of high-strength steels to tubular joints, partly because of concerns about their unique material characteristics. However, the mechanical background behind the limitations is unclear, and its validity needs to be re-evaluated. In this study, a set of CHS (circular hollow section) X-joints fabricated from cold-formed tubes was tested under static axial compression. Then, as supplemental work, extensive test-validated numerical analyses were carried out to investigate further the behaviour of high-strength steel CHS X-joints. In both the testing and the analyses, where three steel grades covering ordinary to very high-strength steels were considered, the high-strength steel joints showed satisfactory structural performance comparable with that of ordinary steel joints in terms of strength and ductility.

Fracture simulation of welded RHS X-joints using GTN damage model

“…Yan et al (2022a) found that neither C f nor the 0.8 f u restriction is necessary for designing HSS rectangular hollow section (RHS) X-joints in tension based on the experimental data presented in (Becque and Wilkinson, 2017; Björk and Saastamoinen, 2012; Feldmann et al, 2016; Tuominen and Björk, 2017; Yan et al, 2022a). The mechanical behaviour of joints beyond the experimental configuration is commonly studied using a verified finite element (FE) model (Björk and Saastamoinen, 2012; Huang et al, 2021; Kim et al, 2019; Lan et al, 2019, 2021; Lee and Kim, 2018; Lee et al, 2017; Liu et al, 2018; Ma et al, 2015; Mohan and Wilkinson, 2022; Tuominen and Björk, 2017; Xin et al, 2021). As the joints fail by a fracture in the heat-affected zone (HAZ) or in the base material (BM), it is essential to conduct an advanced numerical study considering both the stress-strain relationship of HAZ and the material damage model.…”