【作者】 李晓芳；

【导师】 杨晓翔；

【作者基本信息】 福州大学 ， 化学工程， 2006， 博士

【摘要】 在工程上,橡胶与金属粘结件在悬挂与定位系统上得到广泛的使用。在设计过程中,由于橡胶材料的几何与材料双重非线性使我们很难获得问题的简单而精确的解。虽然也存在一些闭式的分析解,但是这些解都是针对简单几何形状的产品,且都是基于两个假设:线弹性小变形和把橡胶看成绝对不可压缩材料。幸运的是,数值技术特别是有限元技术的发展为工程橡胶制品的设计以及优化提供了一个很好的工具。本文主要采用有限元方法对橡胶钢双材料进行非线性有限元分析和破坏机理研究。本文概述了表征橡胶超弹性的基础实验。根据真实的应力应变曲线讨论了橡胶材料模型的局限性。并总结了如何获得有限元分析所必需的应力应变数据及本构模型的选择。对一个存在解析解的经典例子,即橡胶圆柱的扭转问题进行非线性有限元分析,验证有限元法解决橡胶非线性问题的能力。结果表明选择合适的单元,算法和材料模型可以获得与理论解一致的有限元解。用非线性有限元法分析橡胶钢性球模型。计算了不同橡胶层厚度模型的刚度,以及刚度随橡胶材料可压缩性的变化。分析了模型中水静压力分布,预测橡胶钢性球可能失效的位置。用非线性有限元法分析了橡胶纯剪试件变形与理想纯剪变形之间的差异。对橡胶纯剪试件中或橡胶与钢性夹具粘结处存在中心裂纹和边缘裂纹时的撕裂能进行了计算。大裂纹时撕裂能与裂纹尺寸无关,中心小裂纹的撕裂能与裂纹尺寸成线性关系。同时分析了不同材料模型对橡胶纯剪试件变形和断裂属性的影响。文中也计算了裤形试件的撕裂能随拉伸率的变化以及简单拉伸试件中含有不同形状和不同方向的小边缘裂纹时的撕裂能。用非线性有限元法分析了管状橡胶衬套的界面裂纹,对于小裂纹,计算结果与线性分析一致,对于大裂纹,非线性解与线性解存在很大不同,这点是值得注意的。文中还模拟了橡胶钢双材料构件中的另一种失效方式,即空化现象。此外,本文用非线性有限元法对两个实际的橡胶钢粘结件进行分析与重新设计,阐述了有限元法在橡胶材料工程设计及失效分析中的应用。用断裂力学方法预测简单拉伸试件的疲劳寿命,并与实验结果进行比较,根据实验结果,提出了一个新的预测寿命模型。更多还原

【Abstract】 Rubber to metal bonded component are used widely in the engineering industry for applications such as suspension and mounting systems. Nonlinear mechanical properties of rubber in terms of both material and geometric behavior also make it difficult to get simple and rigorous solutions to product design problems. There are a limited number of closed–form analytical equations suitable for application in the design of elastomeric components. However, all appear to deal with components of the most simple geometric shapes and to be based on the assumptions including linear elastic behavior and incompressibility of the rubber. Fortunately, the advent and rapid development of the digital computer and computer based finite element analysis programs handling elastomeric material have provided a powerful means to further the study, understanding, and optimization of rubber in engineering applications. In this paper a thorough mechanical analysis of rubber-steel biomaterial was performed using nonlinear finite element approach. This dissertation mainly contains the following aspects:Describe the experiments of defining rubber material model in this paper. According to the true stress and strain curves the limitations of the material model are discussed. Make a conclusion about how to get stress and strain test data for the purpose of fitting material models in finite element analysis. Perform a nonlinear finite element analysis of torsion of a rubber cylinder which has a theoretical analytical solution. This allows an evaluation of the accuracy of the FEA technique in dealing with rubber material. The results show that with suitable selection of element types, solution algorithms and material models the FEA results consistent with the theoretical solution are obtained.Nonlinear finite element methods are employed to analyze the model of rubber bonded to steel sphere. Values of stiffness are calculated for various thicknesses of the rubber layer with different Poisson’s ratio. They are in good agreement with earlier theoretical solution at small strain. Calculate the hydrostatic pressure distribution in the spherical interface and predict the location of initial failure of the model of rubber bonded to steel sphere.The effects of neglecting deviation from pure shear in the end regions are evaluated using non-linear finite element analysis. Calculations of tearing energy are made for a rubber pure shear specimen with a central crack or a edge crack in the specimen or at the rubber-to-steel bond. The tearing energy is independent of crack更多还原