Model for Predicting Cyclic Behavior of Reinforcing Steel

Abstract

The theoretical relations between the tension and compression stress-strain curves of ductile metals in the natural coordinate system are presented. In addition, a macroscopic model is formulated to predict the cyclic stress-strain behavior of reinforcing steel. The model is based on the natural coordinate system and represents the Bauschinger effect by a simple expression. It also considers the reduction of the unloading modulus with the plastic strain. Furthermore, the reduction of the ultimate tensile strain is taken solely as a function of the maximum compressive strain when the number of cycles is small enough to ignore the effects of low-cycle fatigue. Data collected from tests on New Zealand manufactured steel grades 300 and 430 were used in the calibration of the model. It is shown that the shape of the Bauschinger effect is dependent on the chemical composition of the steel. It is proposed that a generalization of the calibrated model for use in other reinforcing steel types may be possible by considering the carbon content as a variable.