Full-range stress-strain relation of stainless-clad bimetallic steel: Constitutive modelling

Abstract

Stainless-clad (SC) bimetallic steel possesses promising application potential in civil and structural engineering due to a favourable combination corrosion resistance and load-bearing capacity. Nevertheless, the stress-strain models proposed in existing researches are solely suitable for limited grades of SC bimetallic steel. This paper aims to develop a simplified constitutive model applicable to various SC bimetallic steels with different clad-substrate combinations and clad ratios. To this end, the expression of two-stage stress-strain model proposed by Mirambell and Real is selected due to its popularity and recognition. The breakpoint of the two evolutionary stage is determined as the yield plateau termination point of the corresponding substrate metal. Through a thorough analysis on 156 thousands simulated stress-strain curves, the key description parameters of such stress-strain expression, including the strength and strain corresponding to the breakpoint and ultimate point, the tangent modulus and strain hardening components corresponding to two evolutionary stages, were correlated with the influencing factors including the clad ratio, strain and strength indexes of clad and substrate metals. Subsequently, the fitting performances of the proposed constitutive models were validated through existing experimental curves and numerical simulation curves. Accordingly, the different definitions of yield strength and ultimate strength of SC bimetallic steel were compared and discussed.