未硫化橡胶非线性粘弹性本构模型研究

RESEARCH ON NONLINEAR VISCOELASTIC CONSTITUTIVE MODEL FOR UNCURED RUBBER

建立一种新的未硫化橡胶力学行为的描述方法。为了充分研究未硫化橡胶在不同变形模式下复杂的应力-应变行为,设计了3种不同的力学特性实验:单轴拉伸、压缩与剪切试验。发现未硫化橡胶的应力-应变关系表现出很强的非线性和率相关性。提出结合Yeoh应变能函数的广义Maxwell粘超弹性模型,拟合分析表明试验结果与模拟结果一致性较好。发现与硫化橡胶一样,必须采用多工况下的实验数据才能得到变形协调的粘弹性本构模型。实验结果和建立的本构模型有助于工程师更好的理解未硫化橡胶的力学行为,为橡胶的制造过程仿真提供理论基础。

A novel characterization method for the mechanical behavior of uncured rubber is developed in this paper. To fully investigate the complex stress-strain behavior of the uncured rubber under different deformation patterns, three kinds of mechanical tests are designed, i.e., the uniaxial tensile test, the compression test and the shear test. It can be found that the stress-strain relationship of the uncured rubber is highly nonlinear and rate dependent. A generalized Maxwell model combined with the Yeoh strain energy function is proposed to describe the observed phenomena, and a good agreement between the simulation and test is obtained by curve fitting procedure. Furthermore, it is shown that the compatible constitutive model for the uncured rubber can be obtained only by using the experimental data in multiple kind of deformation, which is similar to vulcanized rubber. The experimental results and the established constitutive model are helpful for rubber engineers to understand the mechanical behavior of uncured rubber, and provide theoretical basis for rubber manufacturing process simulation.