Experimental and numerical study of double-sided stainless-clad high-strength steel bolted connections under tensile loading

This research presents a pioneering analysis of the tensile and net-section fracture performance of a novel, double-sided stainless-clad high-strength steel. This composite material achieves an optimal combination of structural load-bearing capacity and corrosion resistance through the synergistic interaction between a Q690D high-strength steel substrate and a 304 stainless steel cladding layer. An experimental programme comprising 19 tests revealed that the tensile behaviour is primarily governed by geometric variables transverse to the loading direction. Observations from both material coupons and connection fracture surfaces confirmed a robust metallurgical bond, with no evidence of separation between the cladding and substrate. This validates the high interfacial integrity produced by the explosive welding technique. The fracture surface exhibited a distinct three-layer morphology characteristic of the welding process. The experimental results were used to develop and validate the finite element model, which facilitated a broader parametric analysis. A subsequent comparative assessment against prevailing design codes showed that EN 1993–1–8:2024 and ASCE/SEI 8–22 provide conservative estimates of tensile capacity. The American specification ANSI/AISC 360–22, however, was found to offer the most accurate predictions for these SCHSS connections.