Yield Strength Analysis of Tantalum in Quasi-Isentropic Compression

For analyzing the quasi-isentropic compression experimental data of solid materials, a backward integration method with strength effect is presented based on rate-dependent constitutive equation and fluid elastic-plastic model. From the quasi-isentropic compression data of tantalum on CQ-1.5 with a loading time of 700 ns, the yield strength, deviatoric stress and interior information of the tantalum sample are calculated. Moreover, the Lagrangian sound speed and strain rate are also analyzed. As a result, the driving history and stress distribution of the tantalum sample are obtained. It is found that the yield strength of 1.85 GPa corresponds to the peak stress (30 GPa) with strain rates of 10 5 s-1, and the isentropic elastic limit is about 2.9 GPa. Numerical results show that the calculated stress-strain and pressure-volume curves appear to be in good agreement with the experimental data from Sandia National Laboratory.