Monday  |  Lakeshore A  |  01:40 PM–02:00 PM

#19691, Simulation of Pore Collapse and Constitutive Modeling of an Energetic Material Simulant: Sucrose

Pore collapse under dynamic shock loading is one of the primary mechanisms of hotspot formation, which leads to ignition and shock to detonation transition (SDT) in energetic materials. X-Ray phase contrast imaging (XPCI) has been employed to observe cylindrical hole collapse in sucrose (an energetic material simulant) when subjected to shock loading. We conducted these experiments at the European Synchrotron Radiation Facility (ESRF), France at the ID19 beamline. An imaging system consisting of three high speed cameras was used to record the subsurface time evolution of several phenomena, including cylindrical hole collapse, jetting and vortex generation.
In this study, numerical simulations are performed to capture the correct shock velocity and observed phenomena like jet and vortex formation. Initially, a Lagrangian method was used to simulate the pore collapse phenomena using Abaqus software. However, due to excess mesh distortion near the pore, the simulations do not reach minimum void volume. This led to conducting numerical simulations using open source code MFC: an Eulerian multi-component, multi-phase, and multi-scale compressible flow solver. The solver uses an interface- and shock-capturing method to resolve material interfaces and shocks, respectively. A complete Mie-Gruneisen equation of state is implemented to model the volumetric behavior. The Johnson-Cook model is used to capture the hypoplastic deviatoric response of sucrose. In most models found in the literature, a constant specific heat is assumed and leads to overestimation of the temperature. In the model, the specific heat at constant volume varies over the temperature range of interest. The MFC simulations show that formation of vortex structures and secondary shock formation leads to an increase in temperature which could be an alternative mechanism of hotspot formation in energetic simulants and materials. The simulations also verify our hypothesis that material shear strength is an important parameter to consider for high pressure impacts.

Srijan Neogi   Brown University
Tom Pilvelait   Brown University
Mirelys Barbosa   Brown University
Mauro Rodriguez   Brown University
David Henann   Brown University
Pradeep Guduru   Brown University