Surrogate models for hotspot ignition and growth rates were presented in Part I (Nassar et al., Shock Waves 29(4):537–558, 2018 ), where the hotspots were formed by the collapse of single cylindrical voids. Such isolated cylindrical voids are idealizations of the void morphology in real meso-structures. This paper therefore investigates the effect of non-cylindrical void shapes and void–void interactions on hotspot ignition and growth. Surrogate models capturing these effects are constructed using a Bayesian Kriging approach. The training data for machine learning the surrogates are derived from reactive void collapse simulations spanning the parameter space of void aspect ratio, void orientation $$ (\theta ) $$ ( θ ) , and void fraction $$ (\phi ) $$ ( ϕ ) . The resulting surrogate models portray strong dependence of the ignition and growth rates on void aspect ratio and orientation, particularly when they are oriented at acute angles with respect to the imposed shock. The surrogate models for void interaction effects show significant changes in hotspot ignition and growth rates as the void fraction increases. The paper elucidates the physics of hotspot evolution in void fields due to the creation and interaction of multiple hotspots. The results from this work will be useful not only for constructing meso-informed macroscale models of HMX, but also for understanding the physics of void–void interactions and sensitivity due to void shape and orientation.

中文翻译：

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在震惊的 HMX 中建模中尺度能量定位，第二部分：训练机器学习的空隙形状和空隙相互作用效应的替代模型

热点点火和增长率的替代模型在第一部分（Nassar 等人，Shock Waves 29(4):537–558, 2018）中介绍，其中热点是由单个圆柱形空隙的坍塌形成的。这种孤立的圆柱形空隙是真实细观结构中空隙形态的理想化。因此，本文研究了非圆柱形空隙形状和空隙-空隙相互作用对热点点火和生长的影响。捕捉这些影响的替代模型是使用贝叶斯克里金法构建的。机器学习替代品的训练数据来自反应性空隙坍塌模拟，涵盖空隙纵横比、空隙方向 $$ (\theta ) $$ ( θ ) 和空隙分数 $$ (\phi ) $$ ( φ)。由此产生的替代模型描绘了点火和增长率对空隙纵横比和方向的强烈依赖性，特别是当它们相对于施加的冲击以锐角定向时。空隙相互作用效应的替代模型显示，随着空隙率的增加，热点点火和生长速率发生了显着变化。该论文阐明了由于多个热点的产生和相互作用而导致的空场中热点演化的物理学。这项工作的结果不仅有助于构建 HMX 的细观宏观模型，而且有助于理解由于空隙形状和方向引起的空隙-空隙相互作用和敏感性的物理学。空隙相互作用效应的替代模型显示，随着空隙率的增加，热点点火和生长速率发生了显着变化。该论文阐明了由于多个热点的产生和相互作用而导致的空场中热点演化的物理学。这项工作的结果不仅有助于构建 HMX 的细观宏观模型，而且有助于理解由于空隙形状和方向引起的空隙-空隙相互作用和敏感性的物理学。空隙相互作用效应的替代模型显示，随着空隙率的增加，热点点火和生长速率发生了显着变化。该论文阐明了由于多个热点的产生和相互作用而导致的空场中热点演化的物理学。这项工作的结果不仅有助于构建 HMX 的细观宏观模型，而且有助于理解由于空隙形状和方向引起的空隙-空隙相互作用和敏感性的物理学。