Microstructurally-Based Constitutive Models for Composite Energetic Materials

Comprehensive energetic models that capture the constitutive response, evolve the microstructural damage, and predict the resulting reactive response are critical to the continued development of large-scale penetrators. In Phase I, Corvid demonstrated the ability of the Coupled Damage and Reaction (CDAR) reactive burn model to simulate the evolution of the microstructure in composite energetic materials for a 1.3 AP-HTPB propellant. Corvid also demonstrated Molecular Dynamics (MD) can increase confidence in CDAR microstructural predictions, while decreasing the data requirements necessary to develop parameter sets for new materials. Building off this success, Corvid will focus on materials with higher concentrations of energetic crystals for polymer binder/stabilizers, like plastic bonded explosives (PBX) such as PAX-3. Corvid proposes the following Phase II tasks: i) enhance the CDAR model to account for crystal fracture and damage, ii) design and execute verification and validation testing on the PBX material to collect data, focusing on microstructural features as they relate to bulk material response, iii) expand the MD-informed constitutive parameterization, iv) provide a constitutive model of a PBX of interest, and v) transition the enhanced CDAR model to government codes like EPIC and CTH via a user-defined material model (UMAT) library for further evaluation and utility.