Discrete Element Analysis On Macro-micro Scale Mechanical Behavior Of Polymer-bonded Particle Composite Pi/SiO₂

As a kind of important structural and functional composites, polymer bondedparticulate-reinforced composites has widespread applications in machinery,construction, aerospace, national defense and electronics fields. These compositespossess the characteristic of strong viscoelasticity and the capacity of largedeformation. There are many difficulties in predicting the behavior of largedeformation and interface failure using conventional finite element method(DEM),such as the simulation of the process of interface debonding and expansion of cracks.In this paper, large deformation simulation on a typical polymer bondedparticulate-reinforced composites PI/SiO2is taken to analyze stress and strainbehavior and the process of interface debonding.First, the numerical simulation of the deformation of polymer matrixparticle-reinforced composite PI/SiO2is taken by PFC2D based on discrete elementmethod. The polymer matrix is dispersed by hexagonally arranged elements and theviscoelastic behavior of polymer matrix material is characterized by viscoelasticBurger’s bond model among discrete elements. The relationship between microscalemodel parameters and macroscale material properties is derived through theoreticalanalysis, and the Burger’s bond model parameters of polymer matrix material aredetermined. Then randomly distributed rigid particles are filled in the matrix model tobuild the DEM model of polymer matrix particle-reinforced composite. Deformationcharacterizations and mechanical performances of the composite with different fillercontent are calculated. Secondly, DEM models of different particle dopping level aregenerated. The analysis of stress and strain is taken to obtain the creep curves, thestress time history curves, the strain ratio time history curves, stress-strain curves,stress and strain contour map, and the influence of different particle dopping level.Finally, four DEM models with different dopping level are generated, and certainconnection strength is given between two contact particles. Simulation of these fourmodels under different loading is taken to observe the dynamic process of matrixdestruction, cracks generation and expansion and interface failure, and to analyze the micro-mechanism of large deformation. The work in this paper will provide a kind oftheoretical guidance of large deformation analysis on polymer bondedparticle-reinforced composite.