Dynamic Shearing Resistance of an Energetic Material Simulant: Sucrose
Dynamic Shearing Resistance of an Energetic Material Simulant: Sucrose
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DOI：
10.1016/j.jmps.2021.104624
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发表时间：
2021-08
影响因子：
5.3
通讯作者：
P. Malhotra;T. Jiao;D. Henann;R. Clifton;P. Guduru
中科院分区：
文献类型：
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作者：
P. Malhotra;T. Jiao;D. Henann;R. Clifton;P. Guduru
蔗糖是β-HMX常用的含能材料模拟物。然而，其在极端载荷条件下的行为仍然知之甚少。为了建立蔗糖的本构模型，进行了压力剪切平板冲击（PSPI）实验。实验在两个不同的标称正应力值，3和9.5 GPa，名义剪切应变率的顺序为10 6 s-1。蔗糖在此压力范围内的剪切强度为400-500 MPa，压力敏感性相对较小。然而，在足够大的剪切应变下，蔗糖中观察到明显的应变软化，在某些情况下甚至剪切阻力急剧下降。本文提出了一种自洽的本构理论来模拟蔗糖的热弹性、热粘塑性响应。对数应变和一组适当的不变量的使用允许分离的柯西应力成压力和偏项。提出了一个完整的Mie-Gruneisen状态方程来模拟体积行为，同时通过Johnson-Cook模型来捕获偏差响应。材料模型能够捕获实验观察结果并预测绝热剪切带形式的局部化，这解释了实验中观察到的蔗糖剪切阻力的灾难性下降。这样的本地化事件进行的热点形成的背景下，高能材料的重要影响，并强调动态剪切强度测量的重要性。
Sucrose is a commonly used energetic material simulant for β-HMX. However, its behavior under extreme loading conditions remains poorly understood. Pressure-Shear Plate Impact (PSPI) experiments have been conducted to provide an experimental foundation for developing a suitable constitutive model for sucrose. Experiments have been performed at two different nominal normal stress values, 3 and 9.5 GPa, with nominal shear strain-rates of the order of 10 6 s− 1. Sucrose exhibits a shear strength of∼ 400-500 MPa in this pressure range, with a relatively small pressure sensitivity. However, pronounced strain softening is observed in sucrose at sufficiently large shear strains-even a dramatic drop in shearing resistance in some cases. A thermodynamically-consistent constitutive theory is presented to model the thermoelastic, thermo-viscoplastic response of sucrose. The use of the logarithmic strain and an appropriate set of invariants allows for separation of the Cauchy stress into pressure and deviatoric terms. A complete Mie-Gruneisen equation of state is presented to model the volumetric behavior while the deviatoric response is captured through the Johnson-Cook Model. The material model is able to capture experimental observations and predicts localization in the form of adiabatic shear bands, which explains the catastrophic drop in shearing resistance of sucrose observed in the experiments. Such localization events carry important implications for energetic materials in the context of hot-spot formation and underline the importance of dynamic shearing strength measurements.