Structural study of TATB under detonation-induced shock conditions

Equations of state for solids at high pressures and temperatures from shock-wave data

This paper deals with the analytic derivation of a complete equation of state (EOS) for solids from shock-wave data in the range of pressures and temperatures, attained by detonation of chemical explosives. The caloric, the thermal and the incomplete EOS are determined as well. An equation for the shock temperature along the Hugoniot curve is derived also.

Sensitivity effects of void density and arrangement in a REBO high explosive

The shock response of two-dimensional model high explosive crystals with various arrangements of circular voids is explored. We simulate a piston impact using molecular dynamics simulations with a Reactive Empirical Bond Order (REBO) model potential for a sub-micron, sub-ns exothermic reaction in a diatomic molecular solid. In square lattices of voids (of equal size), reducing the size of the voids or increasing the porosity while holding the other parameter fixed causes the hotspots to consume the material more quickly and detonation to occur sooner and at lower piston velocities. The early t…

Critical velocities for deflagration and detonation triggered by voids in a REBO high explosive

The effects of circular voids on the shock sensitivity of a two-dimensional model high explosive crystal are considered. We simulate a piston impact using molecular dynamics simulations with a Reactive Empirical Bond Order (REBO) model potential for a sub-micron, sub-ns exothermic reaction in a diatomic molecular solid. The probability of initiating chemical reactions is found to rise more suddenly with increasing piston velocity for larger voids that collapse more deterministically. A void with radius as small as 10 nm reduces the minimum initiating velocity by a factor of 4.

Detonation-induced transformation of graphite to hexagonal diamond

We explore the structural evolution of highly oriented pyrolytic graphite (HOPG) under detonation-induced shock conditions using in-situ synchrotron X-ray diffraction in the ns time scale. We observe the formation of hexagonal diamond (lonsdaleite) at pressures above 50 GPa, in qualitative agreement with recent gas gun experiments. First-principles density functional calculations reveal that under uniaxial compression the energy barrier for the transition towards hexagonal diamond is lower than cubic diamond. Finally, no indication of cubic diamond formation was observed up to >70 GPa.

物理感知深度学习模型用于多尺度冲击起爆模拟中异质含能材料的能量局域化

A physics-aware deep learning model for energy localization in multiscale shock-to-detonation simulations of heterogeneous energetic materials

针对异质含能材料冲击起爆模拟，提出物理感知循环卷积神经网络（PARC）作为替代模型，建模介观能量局域化，降低计算成本并改进亚网格物理表征。

Mapping microstructure to shock-induced temperature fields using deep learning

The response of materials to dynamical, or shock, loading is important to planetary science, aerospace engineering, and energetic materials. Thermal-activated processes, including chemical reactions and phase transitions, are significantly accelerated by the localization of the energy deposited into hotspots. These results from the interaction of a supersonic wave with the materials microstructure and are governed by complex, coupled processes, including the collapse of porosity, interfacial friction, and localized plastic deformation. These mechanisms are not fully understood and today we lac…

一种物理感知深度学习模型，用于模拟冲击含能材料中塌缩孔洞周围的剪切带形成

A physics-aware deep learning model for shear band formation around collapsing pores in shocked reactive materials

本文提出改进的物理感知循环卷积神经网络PARCv2，用于快速预测弱至中等冲击载荷下含能材料中塌缩孔洞周围的剪切带形成与塑性加热，相较于傅里叶神经算子和神经常微分方程模型展现出更优的时空动力学捕捉性能。

Intergranular Hotspots: A Molecular Dynamics Study on the Influence of Compressive and Shear Work

Numerous crystal- and microstructural-level mechanisms are at play in the formation of hotspots, which are known to govern high explosive initiation behavior. Most of these mechanisms, including pore collapse, interfacial friction, and shear banding, involve both compressive and shear work done within the material and have thus far remained difficult to separate. We assess hotspots formed at shocked crystal-crystal interfaces using quasi-1D molecular dynamics simulations that isolate effects due to compression and shear. Two high explosive materials are considered (TATB and PETN) that exhibit …

从原子模型到机器学习：在极端条件下纳米碳的预测性设计

From Atomistic Models to Machine Learning: Predictive Design of Nanocarbons under Extreme Conditions

研究通过机器学习模拟极端条件下纳米碳的形成与转化，探讨淬火-减压条件对纳米碳 allotrope 的影响，提出优化合成路径的方法。