颗粒填充复合材料细观力学行为的数值分析

FINITE ELEMENT ANALYSYS OF MICROMECHANIC BEHAVIOR ON PARTICLE-FILLED MATERIALS

通过三相材料中基体应力分布的分析计算,结合损伤萌生的力学条件,对颗粒填充复合材料的强化效应和增韧效应进行力学分析。计算结果表明,当聚合物受力变形时,刚性无机粒子的存在产生应力集中效应,引发其周围的基体屈服,这种基体的屈服将吸收大量变形功,从而达到增韧效果。文中通过界面的厚度以及界面相材料的刚度对颗粒填充复合材料的力学行为进行分析,对于较薄的界面层,外载作用下基体容易产生脱粘开裂,随着界面厚度的增加,界面屈服的趋势优于基体的脱粘开裂。因此,采用柔性界面层包覆刚性粒子进行填充改性是实现材料强韧化的有效途径。

Based on the mechanical condition of the initiation of damage, the microscopic stress distribution in particle-filled material is studied by RVE（representative volume element）finite element method. The second-phase particle in the form of spheres is modeled as elastic with a ductile interphase between matrix and the rigid particle. Detail parametric analysis of the effects of the size Of particles and the thickness of interfacial layer on the stress distribution are discussed. The results of numerical calculation indicate that debonding has a strong tendency to be initiated when the rigidity of particle is higher than that of the matrix. Thus the toughness of material is difficult to be enhanced. But if a ductile layer is coated with the matrix and the rigid particle, the stress field in the matrix will be strongly affected. As the result, matrix yielding becomes the dominant mode of microdamage. Then both toughening effect and the reinforcing effect on the particle-filled material can be improved.