Molecular mechanics (MM) and molecular dynamics (MD) simulation method were applied to explore the impact of temperature (220–380 K) on the thermostability, sensitivity, and mechanical performance of RDX (1,3,5-trinitro-1,3,5-triazacyco-hexane)/HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane) energetic cocrystal and mixture models. The mechanical property, the maximum trigger bond length (\( {L}_{N-{NO}_2} \)), binding energy, and cohesive energy density (CED) of the pure RDX, β-HMX crystal, the cocrystal, and mixture models were acquired and compared. The results manifest that temperature has an important impact on the binding capacity between the components of the cocrystal and mixture. The binding energies decrease as the temperature rises, and the cocrystal has larger values than those of mixture. For all the models, the \( {L}_{N-{NO}_2} \) increases and the CEDs decrease with the rising temperature, implying that the sensitivity of the explosives increases, while the \( {L}_{N-{NO}_2} \) values of the cocrystal are smaller than those of HMX and the CED values are between those of RDX and β-HMX, indicating that the sensitivity has been enhanced through co-crystallization. As the temperature increases, the shear modulus (G), bulk modulus (K), and tensile modulus (E) values of all models have an evident downtrend. Simultaneously, G, K, and E values of the cocrystal model are less than those of RDX and β-HMX, while the K/G ratio and Cauchy pressure (C₁₂–C₄₄) are larger, signifying that co-crystallization can weaken the brittleness and enhance the ductility of the pure crystals. Compared with the mixture, the cocrystal has better ductility and stability.

中文翻译：

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RDX / HMX高能共晶及其混合物的热稳定性，敏感性和机械性能的比较研究。

应用分子力学（MM）和分子动力学（MD）模拟方法探讨温度（220–380 K）对RDX（1,3,5-trinitro - 1,3 ）的热稳定性，敏感性和机械性能的影响1,5-三氮杂癸烷）/ HMX（1,3,5,7-四硝基-1,3,5,7-四唑烷）高能共晶和混合物模型。机械性能，最大触发键长度（\（{L} _ {N- {NO} _2} \）），纯RDX，β-HMX晶体，共晶体和混合物模型的结合能和内聚能密度（CED）已获得并进行了比较。结果表明，温度对共晶组分和混合物之间的结合能力有重要影响。结合能随着温度的升高而降低，并且共晶的值大于混合物的值。对于所有模型，\（{L} _ {N- {NO} _2} \）随着温度的升高而增加，CED降低，这意味着炸药的敏感性增加，而\（{L} _ { N- {NO} _2} \）共结晶的值小于HMX的值，CED值介于RDX和β-HMX的值之间，表明通过共结晶提高了灵敏度。随着温度升高，所有模型的剪切模量（G），体积模量（K）和拉伸模量（E）值都有明显的下降趋势。同时，共晶模型的G，K和E值小于RDX和β-HMX，而K / G比和柯西压力（C ₁₂ –C ₄₄）较大，表明共结晶会减弱脆性增强纯晶体的延展性。与混合物相比，共晶具有更好的延展性和稳定性。