Nonholonomic Hamiltonian method for multiscale simulation of reacting shock physics

Multiscale methods which are systematic, computationally efficient, and applicable to a wide range of materials are needed to augment experimental research in the development of improved explosives and propellants. A variety of modeling methods have been applied to detonation simulation, but different model formulation techniques are normally used at each scale. This research has developed the first unified discrete Hamiltonian approach to multiscale simulation of reacting shock physics, using a nonholonomic methodology. The method incorporates general material and geometric nonlinearities, which are of central interest in reacting shock modeling applications.

A new synchronous multiscale model has been formulated, which incorporates a macroscale Lagrangian particle-element model, a mesoscale Lagrangian finite element model, and a Lagrangian reacting molecular dynamics model. A new asynchronous multiscale model has been formulated, which incorporates a macroscale Eulerian finite element model, a mesoscale Lagrangian particle-element model, and a Lagrangian reacting molecular dynamics model. The asynchronous model includes new strategies to accommodate the large time and space disparities between scales, and has been validated in simulations which model shock to detonation in two widely used explosives.