Cyclic elastoplastic constitutive model for stainless steels compatible with multiple strengths

Abstract

The application of stainless steel materials in civil engineering has begun to attract attention over the last decade. Nevertheless, most studies of stainless steel structures still use the oversimplified Chaboche model. Therefore a more accurate constitutive model is needed to describe the cyclic elastoplastic behavior of stainless steel. The model should be able to simulate stainless steel of varying strengths and should be easily calibrated for practical engineering purposes. This paper proposes a compatible constitutive model that meets these objectives. The constitutive model combines two forms of hardening, is dominated by isotropic and kinematic hardening, and accounts for the strain memory effect and the average stress relaxation effect. A complete numerical implementation scheme for the constitutive model is proposed and coded in the user material subroutine (UMAT) based on the implicit return mapping algorithm. Furthermore, simplified methods and recommendations for the calibration of material parameters are given. The simulation results of a detailed finite element model are compared with the results of the cyclic loading tests, and good agreements are obtained. The proposed constitutive model can be further used in seismic or other dynamic nonlinear analyses of stainless steel structures to correctly predict their strength, deformation, and energy dissipation capacity.