Comparison of Thermodynamic Equilibrium and Non-Equilibrium Representation of Materials

摘要

Hydrocodes are valuable tools in the modeling of shock wave propagation through solids due to high speed impact phenomena. CTH is a hydrocode built with the ability to use multiple EOSs, including the semi- emperical Mie-Gruneisen EOS and tabular Sesame EOS. Modeling high speed impacts necessitates modeling the non-equilibrium thermodynamic states caused by these impacts. A discussion of the non-equilibrium thermodynamics that may be applied to the region directly behind a shock wave is presented, including details of recent attempts to model non-equilibrium impact phenomena in solids. Also, in order to better determine the applicability of the Mie-Gruneisen EOS anbd the two state PTRAN EOS and the Sesame EOS in situations that include non- equilibrium thermodynamics, the high speed, uniaxial impacts between two iron bars are modeled in CTH. The differences between the Mie-Gruneisen EOS and the Sesame EOS are established. A finite volume uniaxial hydrocode is validated. Finally, CTH is shown to be able to model some irreversibilities occurring in impact phenomena.