Abstract In this study, a systematic experimental program was conducted to understand the stress−strain behavior of a composite solid propellant after different accelerated aging times (30–120 days) with different pre-strains (0%–15%). The effects of accelerated aging time and pre-strain during aging on the mechanical behavior of the propellant were analyzed. The pre-strain effect on the microstructure was observed by a scanning electron microscope to demonstrate the pre-strain dependence of the mechanical behavior of the propellant. The microscopic variation with pseudo-strain was also detected by an optical microscope to analyze the damage process of the propellant. The effects of accelerated aging time and pre-strain on the damage growth were discussed. Finally, a constitutive model was proposed, considering the synergistic effects of viscoelasticity, accelerated aging time, pre-strain during aging, and damage growth. The calibrated model accurately predicted the stress-strain behavior of the composite solid propellant after different accelerated aging times with different pre-strains.

中文翻译：

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加速老化时间、预应变和损伤增长协同作用下复合固体推进剂的力学性能和本构模型

摘要 在本研究中，进行了系统的实验程序以了解复合固体推进剂在不同预应变（0%–15%）下不同加速老化时间（30–120 天）后的应力-应变行为。分析了加速老化时间和老化过程中的预应变对推进剂力学行为的影响。通过扫描电子显微镜观察预应变对微观结构的影响，以证明推进剂力学行为的预应变依赖性。还通过光学显微镜检测了假应变的微观变化，以分析推进剂的损伤过程。讨论了加速老化时间和预应变对损伤增长的影响。最后，提出了一个本构模型，考虑到粘弹性、加速老化时间、老化过程中的预应变和损伤增长的协同效应。校准后的模型准确预测了复合固体推进剂在不同预应变下不同加速老化时间后的应力-应变行为。