Experimental cyclic behaviour and constitutive modelling of hot-rolled titanium-clad bimetallic steel

Abstract

Titanium-clad (TC) bimetallic steel exhibits distinct application potential in coastal building and ocean civil and infrastructure engineering due to its promising corrosion resistance and load-bearing capacity. However, understanding on seismic performance and relevant design methodology of TC bimetallic steel structure is still limited and insufficient to support further engineering application in seismic zones. This paper is intended to clarify the experimental cyclic behaviour and suitable constitutive models of hot-rolled TC bimetallic steel. To this end, a total of 19 cyclic coupon tests are conducted on TC bimetallic steel coupons with the raw surface and polished surface. The important mechanical properties, including the hysteretic stress–strain relationship, cyclic backbones, evolutionary law with regard to the cumulative plastic strain, are thoroughly recorded and compared. The cyclic backbones are fitted through the Ramberg-Osgood model. The influences of cyclic loading protocol type on cyclic behaviour are discussed. Based upon the experimental results, material-dependent parameters of Chaboche isotropic/kinematic hardening model and Giuffre-Menegotto-Pinto constitutive model are calibrated. The fitting performances of such two constitutive models are validated through comparison between experimental results and simulation results. All simulation stress–strain relations show a favourable agreement with the experimental counterparts. The relative errors between most simulation peak stress values and experimental peak stress values are lower than 5.0%. Moreover, the cyclic behaviour of TC bimetallic steel is compared with that of mild structural steels and stainless-clad (SC) bimetallic steel. The experimental results revealed herein and constitutive models calibrated in this paper can lay a solid foundation on subsequent numerical simulation.