Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments

• Published in: Journal of dynamic behavior of materials 2021-06, Vol.7 (2), p.170-187
• Main Authors: Francom, D., Walters, D. J., Barber, J. L., Luscher, D. J., Lawrence, E., Biswas, A., Biwer, C. M., Banesh, D., Lazarz, J., Vogel, S. C., Ramos, K., Bolme, C., Sandberg, R. L., Ahrens, J.
• Format: Article
• Language: English
• Subjects: Chemistry and Materials Science; Continuum modeling; Crystal lattices; Deformation; Diffraction patterns; Dynamic response; Inverse problems; Materials Science; Mechanical analysis; Mesoscale phenomena; Metallic Materials; Parameter sensitivity; Parameterization; Physics; Plate impact tests; RDX; S.I. : High Pressure Strength; Simulation; Single crystals; Solid Mechanics; Statistical models; Thermomechanical analysis; X-ray diffraction
• ISSN: 2199-7446; 2199-7454
• DOI: 10.1007/s40870-020-00254-8

Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a