| The aim of this thesis is the construction of a general purpose simulation tool that can simulate the elements found in an explosive system that include energetic (explosive) and inert (metal) materials. The work presented is mainly two-fold: (1) a thermomechanical model for an energetic material is developed based on a continuum model that uses two independent state variables to represent the phase transformation and the extent of chemical reaction, and (2) a high-resolution model is developed that simulates multi-material, multi-dimensional impact events (in which the energetic material of the first part can be one element) involving detonation and explosion physics. In the numerical model, we attempt to achieve high accuracy with Eulerian finite-difference methods that use essentially non-oscillatory (ENO) scheme and level sets for handling the discontinuities of the flow field, and the Runge-Kutta schemes for a high-order accurate temporal advancing.; The present continuum mechanical model of energetic material is thermodynamically self-consistent and can describe a material that undergoes phase transitions from solid to liquid to gas with exothermic chemical reaction. In various limits, the material is a classical elastic solid, a Newtonian viscous liquid, and a compressible gas.; When modeling systems with energetic material compound, one needs to consider regions where different materials are in physical contact with each other whether the neighboring material is another explosive or a non-reacting inert material. Also one must properly model the material interfaces. These interfaces are tracked by the level set function, introduced as a passive scalar that the continuous pressure and normal velocity conditions are implicitly enforced across these boundaries. Two neighboring materials of distinct equations of state can be brought to contact while their contact surface may evolve according to the local particle velocity.; Because the framework in which the simulation tool is developed is quite general, we expect a wide application of our model to many challenging multi-material physics problems. |
