Flexible nozzle extension technology has been extensively researched throughout the world, but traditional materials cannot meet the growing demands in harsh environments. Short‐cut carbon fiber‐reinforced nitrile rubber (CF/NBR) composites, which are similar to the phenolic impregnated carbon ablator, are currently a hot research topic in this field. The mechanical properties of CF/NBR composites were experimentally tested to study the change in the mechanical behavior of a rocket engine's flexible nozzle extension section under thermal coupling. As indicated by the results, existing models cannot accurately predict changes in materials' mechanical behavior. The theoretical foundation of the nonlinear viscoelastic intrinsic model of rubber is utilized. The uniaxial tensile intrinsic model of CF/NBR composites has been improved by introducing physical parameters, such as fiber reinforcement, strain rate‐dependent correction and temperature‐dependent correction coefficients, and fiber volume fraction. Results show that the intrinsic model developed in this article provides a guide to the uniaxial tensile mechanical behavior of randomly distributed short‐cut CF/NBR composites with known mass‐part formulations and fiber volume fractions at room temperature and under different pyrolysis conditions.

中文翻译：

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不同热解状态下短切碳纤维/丁腈复合材料应变率依赖本征模型的建立

柔性喷嘴延伸技术在世界范围内得到了广泛的研究，但传统材料无法满足恶劣环境下日益增长的需求。短切碳纤维增强丁腈橡胶（CF/NBR）复合材料与酚醛浸渍碳烧蚀剂类似，是目前该领域的研究热点。通过实验测试CF/NBR复合材料的力学性能，研究热耦合下火箭发动机柔性喷嘴延伸段力学行为的变化。结果表明，现有模型无法准确预测材料机械行为的变化。利用橡胶非线性粘弹性本征模型的理论基础。通过引入纤维增强、应变率相关校正和温度相关校正系数以及纤维体积分数等物理参数，改进了 CF/NBR 复合材料的单轴拉伸本征模型。结果表明，本文开发的内在模型为已知质量份配方和纤维体积分数的随机分布短切 CF/NBR 复合材料在室温和不同热解条件下的单轴拉伸力学行为提供了指导。