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At least 325 records · Page 18

A Limited-Ranged Two-Phase Iron Equation of State Model

This report describes the construction of a two-phase EOS for Fe that includes both (hcp) and liquid phases, and which is meant to be valid over the restricted range: V ϵ [4 : 7] °A 3 /atom, and T ϵ [1000 : 20000] K. It was recently used as the basis for a theoretical study of liquid → solid phase transformation kinetics in Fe which appeared in the Supplemental Material for a paper describing a series of NIF shock + ramp compression experiments aimed at constraining the high-P melt curve of Fe.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

GnarlyX: Eulerian multi-material hydrodynamics coupled to equation of state and hyperelastic, plastic constitutive models

GnarlyX is a new hydrocode for direct numerical simulations of the microstructural behavior of high explosives at the mesoscale. We summarize the computational framework for multidimensional, Eulerian multi-material hydrodynamics coupled to EOS and hyperelastic, plastic constitutive models. We present 1D verification tests of multi-material only and combined multimaterial and strength capabilities with comparisons to exact solutions of shock states resulting from an incident shock impacting the material interface of PBX9502 and aluminum. We show that GnarlyX performs well in capturing the resulting shock waves in examining numerical convergence with exact solutions. In later work, we will summarize the thermomechanics and multi-dimensional, parallel computing capabilities in GnarlyX with multi-dimensional verification tests.

42 ENGINEERING↗

SESAME 2163: an updated tin equation of state

This writeup summarizes a new tin EOS, which we refer to as SESAME 2163. The new EOS is very similar to SESAME 2162, containing the β, γ, δ, and ϵ solid phases and the liquid phase. The main differences in 2163 compared to 2162 are: (1) the β-γ phase boundary has been moved slightly higher in pressure, to better agree with recent measurements by Hinton et. al (2020), (2) the γ-δ phase boundary has been moved to slightly lower pressures, (3) the δ-ϵ phase boundary has been adjusted at pressures above 200 GPa to exclude the possibility of melt from the ϵ phase, with δ existing at pressures exceeding roughly 800 GPa, and (4) the melt curve has been moved to lower temperatures based on measurements and recommendations by Briggs et. al. Importantly, we also point out thatthe windows used for multiphase constructionhave changed to the δ phase. We summarize changes in plots showing comparisons of 2162 and 2163 to the relevant experimental data.

36 MATERIALS SCIENCE↗