Accurate Insensitive Munitions Modeling Tool Coupling Detailed Chemical Kinetics and Physical Models

Understanding the response of solid rocket motors under cookoff and projectile impact scenarios is important to the safety of the military’s weapon arsenal. In this SBIR, CFDRC, teamed with Merrill Beckstead of Brigham Young University (BYU), propose to develop an improved modeling tool for simulating the response of solid rocket motors containing AP/HTPB/AL propellant to external heat and impact stimuli. To demonstrate feasibility in Phase I, a cookoff/ignition model recently developed at BYU will be adapted to study fast cookoff of AP/HTPB/AL propellant. Valid condensed-phase decomposition kinetics and detailed gas-phase kinetics for AP/HTPB/AL will be implemented. The cookoff model will be coupled to a 3-dimensional structural mechanics code to incorporate the effects of pressurization on the propellant and surrounding container. This model will accurately estimate pressurization rate and time to explosion for fast cookoff. Alice Atwood of at the Naval Air Warfare Center Weapons Division (China Lake) will team with us to provide validation data from ongoing cookoff experimental tests. In Phase II, the cookoff prediction capability will be tailored to differentiate between fast/slow cookoff behaviors. Condensed-phase physics pertinent to slow cookoff will be implemented. Also, the detailed cookoff model will be integrated into a robust 3D hydrocode to accurately couple effects of additional IM stimuli. Finally, in-depth experimental characterization of IM phenomena will be performed at China Lake.