炭黑填充橡胶复合材料大变形宏细观力学行为研究

In this research, a method that combines experimental research, theoretical analysis and computer simulation has been used to study the macro and micro mechanical behavior of carbon black filled rubber composites within large deformation. Based on the relation of macroscopic and microscopic structure characteristics of carbon black filled rubber composites, Representative Volume Elements with uniform distribution pattern and random distribution pattern have been proposed, and several different kinds of micromechanical numerical models have been established to study and analyze the influence of shape, distribution pattern, particle size, elastic modulus and volume fraction of the carbon black particles on the macro mechanical properties of the rubber composites which include stress-strain behavior, effective elastic modulus, Mullins effect and energy loss. A new theoretical estimation model for effective elastic modulus of filled rubber has been presented, which can better reveal the dependence of the effective elastic modulus of the rubber composites on the volume fraction of carbon black particles at small deformation. A more reasonable macroscopic constitutive model for rubber materials has been put forward, which can give a more accurate characterization of uniaxial tensile mechanical behavior of carbon black filled rubber composites within large deformation, and it lays the theoretical foundations for the design of rubber materials. To explore the effect of carbon black on the mechanical properties of rubber composites, multiple kinds of rubbers filled with different volume fraction of carbon black and unfilled rubber are studied by quasi-static mechanical tensile experiments. And simultaneously, the rationality, the validity and the prediction ability of the macroscopic constitutive model and the micromechanical numerical models are verified by experiments. Finally, the effects of carbon black on the macroscopic mechanical behavior of rubber composites are obtained through the numerical simulation method and the experimental verification method, which provides the theoretical basis and the analytical method for the design of material and structure and also for the security analysis and the performance optimization of material and structure with regard to rubber products.

采用实验研究、理论分析与计算机模拟相结合的方法，对炭黑填充橡胶复合材料大变形宏细观力学行为进行研究。在分析宏观与细观特征之间联系的基础上，提出均匀分布和随机分布形态的代表性体积单元，建立不同的细观力学数值模型，分析炭黑颗粒的形状、分布形态、粒径大小、弹性模量以及体积含量等对橡胶材料宏观应力应变行为、有效弹性模量、Mullins效应及其能量损耗的影响规律。提出新的有效弹性模量理论估计式，更好地反映小变形阶段时炭黑填充量对橡胶有效弹性模量的影响规律。提出更为合理的宏观本构模型，更加精确的表征炭黑填充橡胶材料大变形范围内的拉伸力学行为，为橡胶材料的设计奠定理论基础。采用实验验证宏观本构模型和细观力学数值模型的合理性及其预报能力。通过数值模拟和实验验证手段，研究获得炭黑的填充对橡胶复合材料相关力学行为的影响规律，为橡胶制品相关结构设计选材，材料和结构的安全分析及其性能优化提供理论依据和分析方法。

本项目主要采用实验研究、理论分析与数值模拟相结合的方法，对炭黑填充橡胶复合材料的宏细观力学行为进行了研究。.对不同体积含量的炭黑填充橡胶和未填充橡胶进行了单轴拉伸、循环拉伸加卸载以及多步松弛拉伸加卸载等准静态力学实验，探索了炭黑的填充对硫化橡胶相关力学行为的影响规律。. 在通过电镜试验分析炭黑填充橡胶复合材料的宏观与细观结构特征之间联系的基础上，提出了代表性体积单元，对随机序列吸附算法进行了改进，并通过周期性边界条件的推导及其约束，建立了更为精细、更加符合炭黑颗粒随机分布真实情况的多颗粒夹杂三维细观力学模型，采用非线性有限元分析方法对炭黑填充橡胶复合材料的力学行为进行了研究。主要讨论了炭黑颗粒的形状、分布形态、粒径大小、弹性模量以及体积分数等对复合材料宏观力学行为的影响规律。并采用实验验证了细观力学数值模型的合理性及其预报能力，为橡胶制品相关结构设计、选材、材料和结构的安全分析及其性能优化提供理论依据和分析方法。. 对若干经典本构模型进行了评估，分析了这些模型表征橡胶材料力学性能的优缺点。重点分析了Mooney模型不适用于表征橡胶大变形力学行为的原因，在此基础上，基于Ogden和Treloar的基本假设，提出了一个改进Mooney模型。根据宋名实提出的橡胶本构模型，在八链模型的基础上添加了两个修正项，提出了一个修正八链模型。考虑到橡胶分子之间的相互约束作用，提出了一种考虑分子约束的三链模型，并在此基础上，进一步提出了Mullins模型。最后根据橡胶分子网络分解概念，提出了一个复合本构模型。通过与实验数据对比，这些本构模型都可较好地表征炭黑填充橡胶材料小变形到中等变形范围的力学特性，并对橡胶复杂变形具有良好的预测能力。