Cyclic Behavior of Structural Steels. II: Theory

This paper is concerned with the analytical modeling of the cyclic behavior of structural steels. The modified uniaxial two-surface model developed by Shen et al. in 1992 is generalized to a multiaxial two-surface model, which can treat the cyclic behavior of the structural steels even within the yield plateau. The important features of the cyclic behavior observed in the uniaxial and biaxial cyclic experiments are included in the present model with the extension of the effective plastic strain (EPS) range concept into the multidimensional stress state. The experimental cyclic behavior of mild steel under nonproportional biaxial (torsion-compression) loading histories (in a companion paper) are predicted using the proposed model. It is shown that the proposed model provides a close fit to the experimental results.