An Optimization Framework for Calibration of Material Models

In order to make the process of material model development more systematic for energetic materials, we have developed a procedure that makes use of nonlinear optimization to derive optimal values of parameters in the material models. A framework has been developed that makes use of the optimization software package LS-OPT driving the hydrocode CTH (CTH is developed and maintained at Sandia National Laboratories, LS-OPT is developed by LSTC). CTH was used to model a set of characterization experiments that were used as the basis for the calibration of a particular model; for example, the cylinder test was used to calibrate the JWL equation of state, and the wedge test for the HVRB reactive burn model. As a verification test of the framework, we have determined material model constants for PBX-9404 and compared them to values published in the literature as well as the equation of state library models in CTH.