Thermodynamic, mechanical, and shock response properties of TATB

MSE Seminar
Event Date:
Tuesday, April 18, 2017 - 2:00pm
Location:
MRDC 3515, Hightower Conference Room

Thermodynamic, mechanical, and shock response properties of TATB

Presented by Thomas D. Sewell, Department of Chemistry, University of Missouri-Columbia

1,3,5-triamino-2,4,6-trinitrobenzene (TATB) is of practical interest as a powerful but insensitive high explosive. It is of intellectual interest due to the highly anisotropic triclinic crystal structure in which planar sheets of hydrogen-bonded TATB molecules stack into layers with a graphitic-like packing motif. This structural anisotropy gives rise to pronounced anisotropy in the mechanical and shock response properties. Many of these properties and phenomena are helpful or necessary for the development of high-fidelity mesoscale simulation models, but are difficult or impossible to measure using current experimental techniques. Using atomic-scale simulation methods (mainly molecular dynamics, MD) we have studied several fundamental properties and processes in TATB, including: the PVT equation of state of crystal and liquid, including the melt curve; the elastic tensor; basal-plane plasticity and nano-indentation on basal and non-basal planes; crystal and liquid-state transport coefficients; energy transport from an initial hot spot in oriented crystal; and shock wave response in oriented single crystals and at crystal grain boundaries. I will provide brief vignettes from our studies for several of these topics. I will also make brief mention of a method we have developed recently that allows for the systematic construction of essentially arbitrarily oriented, three-dimensionally periodic homophase or heterophase interfaces involving constituent substances with arbitrary symmetry class. This method, which we have dubbed the Generalized Crystal Cutting Method, enables a wide variety of MD simulations that otherwise would have been quite difficult to perform.

BIOSKETCH:

Thomas D. Sewell is a full professor in the Department of Chemistry at the University of Missouri-Columbia (MU). His research focuses primarily on methods development and applications of atomic- and molecular-scale simulations and theory to condensed phase molecular systems under extreme conditions such as shock wave excitation, intense thermal heating, or large static compression. His interests and experience range from rather fundamental studies of condensed phase chemical dynamics to relatively applied problems in theoretical materials science and multiscale theory and simulation. Sewell has approximately 100 publications in peer-reviewed journals along with a number of invited book chapters and conference proceedings articles. Prior to moving to MU approximately 8.5 years ago to pursue an academic career, Sewell spent about 14.5 years as a technical staff member in the Explosives and Organic Materials Group of the Theoretical Division at Los Alamos National Laboratory. Sewell is on the editorial advisory board of Propellants, Explosives, Pyrotechnics and is an associate technical editor of Journal of Dynamic Behavior of Materials.