纳米TiO2颗粒弱界面增强树脂基复合材料宏观力学行为有限元模拟

基于蒙特卡罗法, 编写了随机分布颗粒增强复合材料的二维代表体积单元生成程序, 建立了纳米颗粒增强树脂基复合材料的有限元模型, 其中采用双线性内聚力模型描述复合材料弱界面的应力与位移关系。通过纳米TiO₂ 颗粒增强环氧树脂基复合材料应力应变行为模拟结果与文献结果对比, 证明了模型的有效性。讨论了弱界面情况下, TiO₂颗粒质量分数与颗粒尺寸对复合材料宏观有效模量的影响, 并对复合材料弱界面渐进损伤过程进行了非线性分析。结果表明: 随着纳米TiO₂颗粒质量分数增加, 复合材料杨氏模量和断裂延伸率均有所增强, 但材料屈服强度有所降低; 相同颗粒质量分数情况下, 随着颗粒尺寸的增大, 颗粒与基体材料之间界面单元总长度减小, 复合材料断裂延伸率有所下降。

Finite element simulation for macroscopic mechanical behavior of nano TiO2 particulate reinforced epoxy composites with weak interface

An algorithm for the automatic generation of 2D representative volume element (RVE) of nano-particle reinforced composites is developed by using Monte-Carlo method. The bilinear cohesive zone model was adopted to evaluate the weak interface traction and separation distance. The macroscopic mechanical behavior of nano TiO2 particle reinforced epoxy composite was simulated by using ABAQUS software, and the validity of model is demonstrated by comparison of test results and simulation results. The effects of TiO2 particle mass fraction and particle size on composite macroscopic effective modulus, and the progressive damage process of composites, were discussed under weak interface condition. The results show that the Young’s modulus and fracture elongation of composite increase gradually with the increasing of mass fraction of TiO2 particle, while the yield strength decreases. Under the same mass fraction of particulate, the total length of interfacial unit between particulates and matrix, and the fracture elongation of composite, were gradually reduced with the increasing of TiO2 particle size.