On the constitutive modeling of a structural steel over a range of strain rates and temperatures

In this study uniaxial tension tests are conducted over a temperature range of 293–800 K and a strain rate range of 0.001–2500/s using a servohydraulic testing machine and an enhanced Hopkinson technique to gain understanding of the plastic flow behavior of a DH-36 steel. Test results reveal the strong dependencies of the flow stress on strain rate and temperature. Moreover, dynamic strain aging (DSA) occurs at temperatures above 450 K, causing an increase in flow stress. As the strain rate increases, the magnitude of the DSA effect reduces while the temperature range over which the DSA induced material strengthening takes place shifts to higher temperatures. Based on the experimental data, a dislocation barrier model is modified to describe the material behavior and to include the DSA effect. Good agreements between the model predictions and the experimental results are obtained.