Comparative Study Of Johnson-Cook Constitutive Model And Steinberg Constitutive Model

Research of physics under extreme conditions is an important direction of physics study in 21st century. Material properties at high-pressure and high-temperature environments, especially induced by strong shock wave, are not only a fundamental problem of condensed matter physics, but also have comprehensive applications in safe protection of space aircraft, weapon physics, new energy, and engineering explosion, etc.Mechanical movement of metals subjected to strong shock wave is controlled by hydrodynamics equations. The elastic-plastic-flow model is adopted to characterize the dynamic behavior of metals. The hydro part is come down to EOS (equation of state) research field, and the elastic-plastic part belongs to constitutive equation research field. The substantial question of high-pressure and high-temperature constitutive equation research is how to measure shear modulus G and yield strength Y precisely. The following are puzzles: (1) because the pressure range is exceed to tenths of GPa, the effects of pressure and temperature to G and Y are considerably large, and the high-pressure physics technique must be utilized to study the G and Y ; (2) the measurement of Y is difficult and the measurement uncertainty is large, although the measurement of G under high-pressure and high-temperature is easy to realize relatively.In this paper, we selected Al, Cu and W as the representations of low, medium and high impedance materials (in addition, Al, Cu are FCC metal, and W is BCC metal). Then experimental data of one-dimensional stress experiments and one-dimensional strain experiments were systematically analyzed in order to obtain the material parameters of Johnson-Cook model and Steinberg model. The applicability of these two constitutive models is comparatively studied by means of numerical simulation method. The principle results are as follows:1. The stress-strain curves of aluminum under temperature ranging from 25 ℃ to 400 ℃ and strain-rate ranging from 10^-4/s to 10³ /s were measured via SHPB (Split Hopkinson Pressure Bar) dynamic compression and MTS (Mechanical Test System) quasi-static compression experiments. Combined with the experimental data of literatures, the material parameters of Johnson-Cook model and Steinberg model for Al, Cu and W were educed.