Simulating Tantalum Strength Measurements on the National Ignition Facility, Z-Machine, and Gas Gun Platforms

The yield strengths of body-centered-cubic refractory metals (e.g. molybdenum, niobium, tantalum, and tungsten) can depend strongly on temperature, pressure, and strain rate. A variety of constitutive models have been proposed to describe these effects, but most are calibrated and/or validated in specific regimes of interest. In this work we used three recently-developed strength models, namely the Livermore Multiscale Model, the Preston-Tonks-Wallace model, and the Kink Pair model, to describe the response of tantalum subjected to elevated temperatures, pressures, and strain rates. We applied these models to predict strength measurements from Lawrence Livermore's National Ignition Facility, Los Alamos' gas gun facilities, and Sandia's Z-Machine, in order to explore a wide range of loading regimes. In this presentation we will outline each approach, and discuss validation results for the models' predictions of the strength of tantalum across a wide range of temperatures, pressures, and strain rates on these high-energy-density platforms.