Abstract This work aims to study the uniaxial dynamic compression response of hexagonal honeycombs with different cell morphologies in the presence of an entrapped gas. A theoretical model is proposed to estimate the dynamic crushing strength of non-auxetic honeycombs while including the effect of the entrapped gas on the crushing process. The theoretical predictions are shown to agree well with the finite element (FE) simulations. From the numerical simulations, Hugoniot relations between the shock velocity and the impact velocity are obtained for various honeycomb geometries. It has been observed that shock velocity varies almost linearly with impact velocity. Using this fundamental relation, we derive the stress-impact velocity Hugoniot from the conservation law of momentum. The dynamic stress-strain states of a regular hexagonal honeycomb obtained from the FE simulations show a good agreement with the Hugoniot predictions. It is shown that the dynamic stress-strain states for various impact velocities lie on a unique curve, which is different from the quasi-static stress-strain response. The local strains behind the shock front are significantly lowered in the presence of an entrapped gas, and the stresses behind the shock front are higher as compared to the case where there is no entrapped gas. The variation of the plateau stresses with the cell morphology has been explained, and correlated to the energy absorption capacity of the honeycombs. A new method to characterize the energy absorption capacity of honeycombs is proposed, and the performance of various honeycombs has been compared through the dissipation performance parameter.

中文翻译：

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含气体的拉胀和非拉胀六边形蜂窝的动态压缩行为

摘要 本工作旨在研究在夹带气体存在下具有不同蜂窝形态的六边形蜂窝的单轴动态压缩响应。提出了一种理论模型来估计非拉胀蜂窝的动态抗压强度，同时包括夹带气体对压碎过程的影响。理论预测与有限元 (FE) 模拟非常吻合。从数值模拟中，获得了各种蜂窝几何形状的冲击速度和冲击速度之间的 Hugoniot 关系。已经观察到冲击速度几乎随冲击速度线性变化。使用这个基本关系，我们从动量守恒定律推导出应力-冲击速度 Hugoniot。从有限元模拟获得的正六边形蜂窝的动态应力应变状态与 Hugoniot 预测非常吻合。结果表明，不同冲击速度下的动态应力应变状态位于一条独特的曲线上，这与准静态应力应变响应不同。在存在夹带气体的情况下，激波前缘后面的局部应变显着降低，并且与没有夹带气体的情况相比，激波前缘后面的应力更高。已经解释了平台应力随细胞形态的变化，并与蜂窝的能量吸收能力相关。提出了一种表征蜂窝能量吸收能力的新方法，