Research on parameter estimation of Johnson-Cook constitutive model

In order to investigate the mechanical properties of BT3-1 titanium alloy and compare parameter estimation results of Johnson-Cook constitutive model by different algorithms and experimental conditions, the real stress-strain curves of the material were obtained by mechanical properties experiments. A variety of common algorithms were selected to estimate the parameters of the material constitutive model, and the influence of the results was analyzed by different strain rate and temperature data processing methods. The results indicate that the elastic modulus and flow stress of BT3-1 titanium alloy have different sensitivity to variability in the quasi-static compression test, the material has obvious softening effect with temperature, and it is accompanied by a certain strain rate strengthening phenomenon in the SHPB test. The actual strain rate fluctuates around the nominal strain rate, and the actual temperature change is affected by the nominal strain rate and the nominal temperature. Different parameter estimation algorithms will cause different calculation time and estimation results; When estimating the parameters by using the SHPB experiments data, it will result in a large estimated deviation if the nominal strain rate and temperature data are adopted, consideration should be given to temperature changes during the loading process. © 2020, Science Press. All right reserved.