Determination of shear behavior and constitutive modeling of the 603 steel over wide temperature and strain rate ranges

A new double shear specimen (DSS) is used to study the plastic flow behaviors and constitutive models of the 603 steel under shear loading. Shear stress-shear strain curves are obtained over large ranges of temperatures (93-673 K) and shear strain rates (0.001-35,000 s(-1)). The stress state effect on the plasticity of the material has been studied particularly through the comparison of the test results with the experimental data under uniaxial compression. An obvious elevation of the flow stress levels and the strengthening of the work-hardening effect are observed in the compressive tests, indicating an important stress state effect on the plastic behaviors of the material. A constitutive model JC1 is determined by the present tests, which in numerical simulation shows much more precise prediction on the strain waves and the flow stress curves than the compression-based model, JC2. A shear dominated stress state is obtained in the shear zone, in which the stress triaxiality and the Lode angle parameter are both very low. Therefore, in this work the effects of stress state and strain rate have been decoupled successfully at high strain rates, and the stress state effect on the mechanical properties is largely avoided. It implies that without the consideration of the stress state effect, the equivalent stress-equivalent strain relation may fail to describe the plastic behavior of the material accurately. In engineering application, the actual stress/strain state must be considered in the determination or selection of the constitutive models to obtain a precise computation result. (C) 2019 Elsevier Ltd. All rights reserved.