Modeling tantatlum hole closure experiments to assess constitutive models at high strain rates and large strains

We present numerical simulations and experimental results for tantalum hole closure experiments performed using the high-rate imaging systems within the Dynamic Compression Sector located at the Advanced Photon Source. The hole closure platform uses a cylindrically convergent geometry to produce large deformation at strain rates of 10^5/s and higher. In this study, we developed an updated configuration that uses a two-layer flyer and elongated target to mitigate the deleterious effects of porosity and anelasticity. The updated configuration allowed us to assess the capability of simpler constitutive models when materials are subjected to extreme conditions, such as strains that significantly larger than traditional plate impact experiments while achieving similar pressure and strain rates. Results from the updated experimental configuration are used to evaluate commonly-used strength models for tantalum.