Continuum Modeling of Novel Molecular and Aluminized Enhanced Effects Explosives
Abstract
We propose to develop new continuum-based models for three classes of explosive materials: 1) A novel class of molecular explosives,, Redox Frustrated Hybrid Energetic Materials (RFH-EM), developed at Temple University in the Zdilla-group (that attach fuel and ox,idizers ligands to a metal anion nitrogen molecular cage). 2) Known high performance molecular explosives CL-20 and Fox-7, with cont,rasting properties that are currently being studied with atomistic simulations in the Goddard-group at California Institute of Techn,ology (CalTech). 3) Aluminized combined effects explosives (CEX, for which PAX-30 is representative). The Goddard and Zdilla gro,ups? current collaboration uses quantum-mechanical molecular dynamics (QM-MD) and reactive molecular dynamics (RMD) simulations to s,tudy decomposition kinetics of the novel, RFH-EM, that have been shown to exhibit a large increase in chemical energy density relati,ve to CHNO molecular explosives. The Stewart-group efforts at University ofFlorida (UF) would add continuum-based modeling and scale,-bridging simulations to the a) material design and synthesis of RFH-EM at Temple and b) material design and atomistic simulation at, CalTech. The planned mutual collaboration (already agreed on) would see the three efforts feed information to each other as RFH-EM,research proceeds and accelerate discoveries. We propose to develop detailed continuum-based models to simulate the properties and, behaviors of explosives CL-20 and Fox-7, with contrasting properties, that are being studied by the Goddard-group with RMD (Reax-FF,) and QM-MD. The Stewart-group will use a physical chemistry-centric modeling framework to describe averaged properties of reduced c,omponents, to interpret experimental and atomistic-based simulations of both novel RFH-EM and the CL-20/Fox-7 pair. The Stewart-grou,p models, assume: A priori specification of all components in a reduced kinetics scheme, that includes those with initial, large, in,termediate and lowmolecular weights components. In collaboration with our CalTech colleagues we will define a reaction scheme, at le,ast partly based on RMD and QM-RMD simulations. The reduced components, once chosen for particular version of the continuum-model,,are assigned distinct molecular weights and require: The specification of equations of state forms, with a common mixture stress and, temperature. Arrhenius rate forms with activation energies for the reaction. Mass and thermal transport terms and or other effects,that model phase transformation, mechanical plasticity and damage, if they are observed in the atomistic simulation and deemed requi,red. We also propose to model aluminized explosives similar to PAX-30 with an emphasis placed on understanding early time energ,etic release from aluminum combustion. Modeling and simulation will be carried out at the micro-scale, (not the atomistic scale), to, resolve energetic events amongst the initially separated reactants, (like HMX grains, aluminum ,tative volume element (RVE). Understanding early time energetic release from aluminum combustion will likely point to formulation c,hanges that will lead to increased performance. We have been invited and agreed to join a collaboration with explosive formulator Ma,rk Mason at NWAC who is working with research staff at the Air Force Munitions Directorate, Eglin AFB, FL (AFRL/RW). The work on a,luminized explosive will likely develop new information about mechanisms that can be used to design new diagnostic experiments to lo,wer development time required to optimize performance of CEX and similar explosives.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 06, 2022
- Source ID
- N000142312113
Entities
People
- D. Scott Stewart
Organizations
- Office of Naval Research
- United States Navy
- University of Florida