Tests and modelling on cyclic behaviour of stainless-clad bimetallic steel

Abstract In order to study the constitutive relation of stainless-clad (SC) bimetallic steel under earthquake actions, tests of 23 specimens prepared from 316L+Q235B SC bimetallic steel plate with a nominal thickness of 3 + 5 mm are carried out, in which tensile and compressive monotonic loadings as well as 15 different cyclic loading spectrums are incorporated. Based on the test results, monotonic and hysteretic behaviour, macro- and micro-failure characteristics are analysed. Through comparison and analyses, it is indicated that the envelope curves of the SC bimetallic steel under cyclic loadings are markedly higher than the monotonic tensile curves, which demonstrates that the cyclic hardening effect is significant. Both isotropic and kinematic hardening characteristics are observed, i.e. the cyclic behaviour of the SC bimetallic steel exhibits a typical combined hardening effect. In addition, it is found that envelope curves of the SC bimetallic steel may be described well by using the Ramberg-Osgood (R-O) three-parameter model, of which the parameters are updated though nonlinear fitting of the test data. To develop a constitutive model for simulating the cyclic behaviour of the SC bimetallic steel, the Chaboche plastic constitutive model is employed herein, and its relevant parameters are updated and calibrated. By using the adapted Chaboche model in finite element (FE) analyse through ABAQUS, the cyclic behaviour of all the test specimens are simulated. It is found that the simulated curves obtained from the FE model results agree well with the test curves, which demonstrates that the constitutive model proposed herein is adequate for evaluating the cyclic responses of the SC bimetallic steel. The research outcomes may provide an important basis for accurate analyses of structures fabricated from the SC bimetallic steel under earthquake actions.