UTILIZATION OF VERSATILE TABLETOP EXPERIMENTAL DIAGNOSTICS TO CHARACTERIZE MATERIALS RESPONSE
We strive to enhance our ability to more confidently design or predict the performance, safety, and reliability/assurance of munition systems by developing experimentally constrained semiempirical models. In this talk, we will briefly discuss three versatile tabletop diagnostic tools used to characterize mechanical and/or chemical properties of energetic materials including polymers and detonation products. We utilize ultra- fast laser-based compression experiments to further elucidate wave dynamics within single crystal HEs - to aid in the development of plasticity models- and for polycrystal-line HEs or polymers to measure unreacted equations of state (EOS) up to higher particle velocities than accessible by longer timescale compression platforms. We apply photo- acoustic light scattering to measure adiabatic sound-speeds from virtually any dense fluid (detonation products and mixtures) in order to constrain the parameterization of exponential-6 intermolecular interaction potentials used within semi-empirical thermodynamic based predications of detonation performance. In a third example, we have recently proven that one can use white-light optical interferometry with microscopy to measure P-V EOS curves (to 10s of GPa) of energetic materials or polymers or PBXs and thus complement conventional DAC EOS measurement techniques such as synchrotron-based X-ray diffraction. The advantages and disadvantages of an all-optical approach to direct pressure dependent volume mea- surements will be presented. The impact of using tabletop diagnostics to characterize materials is that they greatly enhance data throughput with, in the long run, reduced costs. The small length-scale of high-pressure tabletop measurements (< mm) may imply that deflagration-to-det- onation studies are not feasible i.e., tabletop compression platforms. However, the ability to rapidly characterize high-strain-rate response of HEs or polymers serves well to direct larger platform tests to study the most promising material systems. Moreover, semi-empirical derived predictions serve well to guide large-scale munitions tests and thus ultimately enable us to more rapidly reach mission objectives with less cost and danger to personnel.
This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
JOSEPH (JOE) ZAUG is the founder and group leader of the experimental component of the reaction dynamics group within the Materials Sciences Division at Lawrence Livermore National Laboratory. He has over twenty-five years of hands-on experience innovating laser-based diagnostic tools to address long-standing grand-challenge science issues that cut across multiple disciplines such as geophysics, high-pressure physics and chemistry including chemical synthesis, and materials science. In 2003-2004 he co-developed the first (and only) dedicated high-pressure synchrotron beamline 12.2.2 in the western U.S. including the experimental end-station at Lawrence Berkeley National Laboratory's Advanced Light Source. Joe's team works with international and U.S. collaborators and receives funding from DOE and DOD sponsors to advance U.S. national defense programs and initiatives.