Pagosa Simulation of Hypervelocity Impact and Fragmentation From Hypersonic Explosions

Abstract

We use PAGOSA’s FLIP+MPM capability to simulate hypervelocity impact and fragmentation from hypersonic explosions. The scenario to be simulated involves a complex chain explosion from fragmentation impact which was caused by another explosion. The simulations also use the SURF model for shock to detonation transition (SDT) and the MATCH model for mechanical ignition and deflagration of high explosives. These models in PAGOSA working together are crucial for modeling complex system for real world applications. This shows the powerful modeling and predicting capability of PAGOSA that others cannot do. Since experimental data are not available for any complex scenario like this, we did verification and validation (V&V) in each separate steps, These include the fragmentation simulated by FLIP+MPM, the Shock to Detonation Transition (SDT) modeled by SURF and mechanical ignition and deflagration modeled by MATCH. PAGOSA is a shock hydrodynamics program developed at Los Alamos National Laboratory (LANL) for the study of high-speed compressible flow and high-rate material deformation. PAGOSA is a three-dimensional Eulerian finite difference code, solving problems with a wide variety of equations of state (EOSs), material strength, and explosive modeling options. It has high efficiency for simulations running on massively parallel supercomputers. It is a multi-material code using volume of fluid (VOF) interface reconstruction and second order fully explicit time integration. Standard von Neumann artificial viscosity is used. Newly added material point method (MPM) plus Fluid-Implicit Particle (FLIP) capability can simulate high-speed metal fragmentation.