Wei Wei, Yuan Yong, Gao Xiaoyu
School of Civil and Hydraulic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
Polymers (Basel). 2020 Oct 11;12(10):2322. doi: 10.3390/polym12102322.
Filled rubber has been extensively used in the repairing, retrofitting, and protecting of civil infrastructures due to its superior physical and mechanical properties. However, effects of large deformation and velocity impacts on the mechanical behavior of filled rubber are not well recognized, one of the major challenges in the past investigations is that the material exhibits significant nonlinearity and sensitivity to velocity. This paper presents a hyper-viscoelastic constitutive modeling and experimental study to capture both the hyperelastic and viscoelastic behaviors of filled rubber under large shear deformation and velocity impacts. Motivated by the micro-mechanism of filled rubber, the constitutive modeling consists of an equilibrium element in parallel with an improved Maxwell element to incorporate both nonlinear hyperelasticity and rate-dependent performance governed by the readjustment and rearrangement of molecular chains in the material. A new strain energy function is developed and the physical description of parameters in the strain energy function is highlighted. The Clausius-Duhem inequality is employed to consider the thermodynamic consistency of the model. Then, stress relaxation property and stress-strain response of filled rubber upon cyclic shear loading with different strain rates (ranging from 0.08 to 12.0 s) are experimentally studied, and some key observations are summarized. Subsequently, a "Gau-Poly" function is proposed based on the experimental data to describe the viscoelastic property of filled rubber versus strain and strain rate. Finally, stress-strain relationship and hysteretic area obtained from the experimental results were compared with the numerical results of the model, good agreement was achieved and the capacity of the model to accurately reproduce the mechanical behavior of filled rubber under a wide range of deformation and velocity impacts was verified.
由于其优异的物理和力学性能，填充橡胶已广泛应用于土木基础设施的修复、翻新和保护。然而，大变形和速度冲击对填充橡胶力学行为的影响尚未得到充分认识，过去研究中的一个主要挑战是该材料表现出显著的非线性和对速度的敏感性。本文提出了一种超粘弹性本构模型及实验研究，以捕捉填充橡胶在大剪切变形和速度冲击下的超弹性和粘弹性行为。基于填充橡胶的微观机制，本构模型由一个与改进的麦克斯韦单元并联的平衡单元组成，以纳入材料中分子链重新排列和调整所控制的非线性超弹性和速率依赖性性能。开发了一种新的应变能函数，并突出了应变能函数中参数的物理描述。采用克劳修斯-杜亥姆不等式来考虑模型的热力学一致性。然后，对填充橡胶在不同应变率（范围为0.08至12.0 s）的循环剪切加载下的应力松弛特性和应力-应变响应进行了实验研究，并总结了一些关键观察结果。随后，基于实验数据提出了一个“Gau-Poly”函数来描述填充橡胶的粘弹性与应变和应变率的关系。最后，将实验结果得到的应力-应变关系和滞后面积与模型的数值结果进行了比较，取得了良好的一致性，并验证了该模型在广泛的变形和速度冲击下准确再现填充橡胶力学行为的能力。
