填充橡胶温度依赖的非弹性力学行为实验研究

An Experimental Investigation on the Temperature-dependent Inelastic Behaviors of Filled Rubber

填充橡胶具有复杂的非弹性力学行为,主要包括应变率依赖的粘弹性效应和变形历史依赖的Mullins效应.当前大多数对填充橡胶的实验研究集中于室温条件,针对以上问题,本论文通过单轴压缩实验系统地研究了温度对氟橡胶粘弹性和Mullins效应这两种非弹性行为的影响.首先采用多次循环加载获得了完全消除了Mullins效应的预处理试样.通过对原试样和预处理试样的单轴加卸载实验应力响应进行对比,发现Mullins效应不受变形温度和应变率的影响.通过对消除Mullins效应橡胶材料应力松弛实验结果进行分析,发现粘弹性行为不仅与变形的温度、应变率相关,还受加载应变的影响,表现为较大的加载应变会抑制氟橡胶的应力松弛.

Filled rubbers have been widely used in various industrial applications,including tires,sealing materials,shock absorbers,artificial muscles and soft robotics.They exhibit complex inelastic behaviors,including the rate-dependent viscoelastic effect and the deformation-history-dependent Mullins effect.In the past,various studies have been conducted to characterize the mechanical behaviors of filled rubber.However,most of these studies were either performed at room temperature or only focused on one type of the inelastic behaviors.To overcome this limitation,in this work,we performed a series of experiments to investigate the influences of temperature and strain rate on the Mullins effects and viscoelastic behaviors of a filled rubber Viton.To separate the coupled response due to viscoelastic and Mullins effects,repeated loading-unloading tests were conducted to obtain the preconditioned specimens without the Mullins effect.Thus,under the same loading condition,the difference between the stress responses of the virgin specimens and the preconditioned specimens is only contributed by the Mullins effect.The results show that the Mullins effect is independent of temperature and deformation rate.Uniaxial compression tests were also performed on the preconditioned specimens at different temperatures and strain rates.The results show that the viscoelastic response is significantly influenced by temperature and strain rate.At lower temperatures,an obvious strain hardening response can also be observed.The results of the stress relaxation tests demonstrate that the applied strain also affects the viscoelastic behaviors.More specifically,a large applied strain suppresses the stress relaxation of Viton.These results can facilitate our understanding of the inelastic behaviors of filled rubber.