Abstract The deformation behavior of solid polymers under isothermal, quasi-static loadings is investigated. A comprehensive test program consisting of tension, torsion, and combinations thereof was conducted on a polycarbonate polymer under both monotonic and long-term cyclic loadings. The effects of different loading modes, creep load conditions, mean stress, stress amplitude, and loading rate are addressed. The possibility of simulating costly tests with existing models is also demonstrated. A viscoelastic-viscoplastic constitutive model proposed by Barriere et al. 2019 is applied for this purpose. Compared to state-of-the-art models, this model requires a reduced set of material parameters to be defined. The validation experiments demonstrate the model robustly predicts various loading scenarios. In light of both the experimental and model results, the material shows an apparent hardening with increasing loading rates, and the ratcheting strain increases with the stress amplitude and mean stress. When applying the same stress ratio, stress rate, and maximum axial and torsional stresses relative to the strengths, the superimposed tension increased the torsional ratcheting for all load combinations. The ratcheting-fatigue failure interaction is also investigated. The experimental data show the interaction at least 90% of the fatigue life, which the important observation is used for the development of a fatigue model.

中文翻译：

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大单调长期循环变形下固体聚合物的测试与分析

摘要 研究了等温、准静态载荷下固体聚合物的变形行为。在单调和长期循环载荷下对聚碳酸酯聚合物进行了由拉伸、扭转及其组合组成的综合测试程序。讨论了不同加载模式、蠕变载荷条件、平均应力、应力幅值和加载速率的影响。还展示了使用现有模型模拟昂贵测试的可能性。Barriere 等人提出的粘弹-粘塑性本构模型。2019 年适用于此目的。与最先进的模型相比，该模型需要定义一组减少的材料参数。验证实验表明该模型可以稳健地预测各种负载情况。根据实验和模型结果，材料随着加载速率的增加表现出明显的硬化，棘轮应变随着应力幅度和平均应力的增加而增加。当应用相同的应力比、应力速率以及相对于强度的最大轴向和扭转应力时，叠加的张力增加了所有载荷组合的扭转棘轮。棘轮疲劳失效相互作用也进行了研究。实验数据显示交互作用至少占疲劳寿命的 90%，重要的观察结果用于疲劳模型的开发。以及相对于强度的最大轴向和扭转应力，叠加张力增加了所有载荷组合的扭转棘轮。棘轮疲劳失效相互作用也进行了研究。实验数据显示交互作用至少占疲劳寿命的 90%，重要的观察结果用于疲劳模型的开发。以及相对于强度的最大轴向和扭转应力，叠加张力增加了所有载荷组合的扭转棘轮。棘轮疲劳失效相互作用也进行了研究。实验数据显示交互作用至少占疲劳寿命的 90%，重要的观察结果用于疲劳模型的开发。