SBIR-STTR Award

We propose to develop a set of multiscale modeling tools for structural energetic materials (SEMs) that explicitly treat microscale, mesoscale and macroscale coupling of mechanical response, thermal properties and chemical reactions.At the macroscale, a combined material point method (MPM, solid)/Eulerian (ICE, fluid) methodology, MPM-ICE, will be employed to investigate the behavior of select Al/Ni intermetallic SEMs and SEM/PBX-9501 devices as a function of device geometry for various loading and impact scenarios.While some properties and material response models for the macroscale simulations will be taken from the literature or our previous work, many, including EOS, constitutive laws, and frictional heating for the SEM, will be obtained from mesoscale simulations of the SEM carried out using MPM.Here the individual phases (e.g., Al and Ni particles, voids, and interfaces) are considered explicitly and numerical simulations are conducted in order to obtain homogenized material response laws and models that depends upon the microstructure.These microstructure dependent models can be employed in mesoscale simulations utilizing a stochastic seeding approach.Finally, many properties and response models for the individual phases and interfaces (e.g., Al/Ni contact models) needed for the mesoscale simulations will be obtained using atomistic molecular dynamics (MD) simulations.

We propose to develop a set of multiscale modeling tools for structural reactive materials (SRMs) that explicitly treat microscale, mesoscale and macroscale coupling of mechanical response, thermal properties and chemical reactions. At the macroscale, a combined material point method (MPM, solid)/Eulerian (ICE, fluid) methodology, MPM-ICE, will be employed to investigate the behavior of select intermetallic SRMs that will experience various shock impact scenarios. Most properties/materials models for macroscale simulations will be obtained will be obtained from mesoscale simulations of the SRM carried out using MPM where the individual phases (e.g., Al and Ni grains and interfaces) are considered explicitly and numerical simulations are conducted in order to obtain stochastic homogenized material response models that depends upon the microstructure.Properties and constitutive models for the individual phases and interfaces (e.g., Al/Ni contact models) needed for the mesoscale simulations will be obtained using reactive atomistic molecular dynamics. In Phase II the proposed multiscale modeling approach will primarily focus on accurate description of SRM reaction and failure mechanisms. Correlations between SRM microstructure and device performance characteristics such as fragments size and shape distribution, flying time, reactivity, and energy release upon target impact will be key design objectives.