Implementation of Tillotson Equation of State for Hypervelocity Impact of Metals, Geologic Materials, and Liquids

The Tillotson equation of state (EOS), which was originally developed for the hypervelocity impact of metals, was augmented with an additional region in expansion to provide full coverage of the density-energy space and a new cavitation model for liquids. This EOS was implemented into CTH, Sandia National Laboratories Eulerian, finite-volume, shock physics code, for the general purpose of simulating hypervelocity impacts of metals, geologic materials, and liquids; however, the salient features of this EOS in both compression and expansion are evaluated for water given the ubiquity of available data. Addition of a cavitation model allows for treatment of liquid spall when the local pressure drops below the vapor pressure in events such as underwater blasts and high speed projectiles or fragments in liquids. The EOS is evaluated by comparing the response to previously published dynamic compression experiments. Additionally, the model results are compared against the Mie-Gruneisen and SESAME equations of state already in the CTH database.