Dong Yifeng, Fu Yutong, He Chunwang, Fang Daining
Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China.
Beijing Key Laboratory of Lightweight Multi-Functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, China.
Polymers (Basel). 2023 Jul 13;15(14):3033. doi: 10.3390/polym15143033.
Rubber composites are hyperelastic materials with obvious stress-softening effects during the cyclic loading-unloading process. In previous studies, it is hard to obtain the stress responses of rubber composites at arbitrary loading-unloading orders directly. In this paper, a hyper-pseudoelastic model is developed to characterize the cyclic stress-softening effect of rubber composites with a fixed stretch amplitude at arbitrary loading-unloading order. The theoretical relationship between strain energy function and cyclic loading-unloading order is correlated by the hyper-pseudoelastic model directly. Initially, the basic laws of the cyclic stress-softening effect of rubber composites are revealed based on the cyclic loading-unloading experiments. Then, a theoretical relationship between the strain energy evolution function and loading-unloading order, as well as the pseudoelastic theory, is developed. Additionally, the basic constraints that the strain energy evolution function must satisfy in the presence or absence of residual deformation effect are derived. Finally, the calibration process of material parameters in the hyper-pseudoelastic model is also presented. The validity of the hyper-pseudoelastic model is demonstrated via the comparisons to experimental data of rubber composites with different filler contents. This paper presents a theoretical model for characterizing the stress-softening effect of rubber composites during the cyclic loading-unloading process. The proposed theoretical model can accurately predict the evolution of the mechanical behavior of rubber composites with the number of loading-unloading cycles, which provides scientific guidance for predicting the durability properties and analyzing the fatigue performance of rubber composites.
橡胶复合材料是超弹性材料，在循环加载-卸载过程中具有明显的应力软化效应。在以往的研究中，很难直接获得橡胶复合材料在任意加载-卸载顺序下的应力响应。本文建立了一个超伪弹性模型，以表征橡胶复合材料在任意加载-卸载顺序下、固定拉伸幅度时的循环应力软化效应。超伪弹性模型直接关联了应变能函数与循环加载-卸载顺序之间的理论关系。首先，基于循环加载-卸载实验揭示了橡胶复合材料循环应力软化效应的基本规律。然后，建立了应变能演化函数与加载-卸载顺序之间的理论关系以及伪弹性理论。此外，推导了应变能演化函数在有或无残余变形效应时必须满足的基本约束条件。最后，还给出了超伪弹性模型中材料参数的校准过程。通过与不同填料含量橡胶复合材料的实验数据进行比较，验证了超伪弹性模型的有效性。本文提出了一个用于表征橡胶复合材料在循环加载-卸载过程中应力软化效应的理论模型。所提出的理论模型能够准确预测橡胶复合材料力学行为随加载-卸载循环次数的演变，为预测橡胶复合材料的耐久性性能和分析其疲劳性能提供了科学指导。
