Prediction Of The Strength And The Stiffness Of Filled Polymer Composite

Polymer composites,which are characterized with their outstanding mechanical properties,low weight and shaping easily,are widely used in the so many domains such as aerospace,automobile,health care and sports.Among all the properties,mechanical properties have been the focus of peoples.Many researchers have been conducting experiments and doing researches to improve the mechanical properties of polymer composites.And among all the mechanical properties,tensile strength and elastic modulus are the key indicators.The tensile strength and elastic modulus of short fiber/particles/polymer composites are studied in this paper.The predicting formulas of the tensile strength and elastic modulus are proposed.The main contents are as follows:(1)By analyzing the debonding stress of particle and matrix,and considering the influence of particle cluster,a predicting formula for the tensile strength of spherical particle filled polymer composites is put forward.This formula is suitable for the composites in which there is good interface adhesion between particles and matrix.(2)The influence of fiber end and the influence of fiber cluster are taken into consideration.The fiber end is modeled as a semi-sphere.The debonding stress and the crack stress of fibers are considered comprehensively.A predicting formula for the tensile strength of unidirectional short fiber filled polymer composites is presented.(3)Based on the studies from chapter 2 and chapter 3,the influence of fiber cluster and particle cluster is considered comprehensively.A prediction for the tensile strength of short fiber and particle filled hybrid polymer composites is proposed.(4)The Halpin-Tsai model and laminate analog approach are applied.By considering the influence of material porosity,A prediction of the anisotropy of the elastic modulus for hybrid composites reinforced by short fibers and particles is made.The results show the reinforcing hybrid effect.A approach to find the optimal design for the elastic modulus of composites in a random 3D direction is presented.The comparison between the theory in this paper and experimental data is made,is shows that the prediction matches very well with experimental data,which shows the correctness and accuracy of the theory in this paper.The study in this paper can provide a guidance to improve the tensile strength and elastic modulus of polymer composites in practical engineering application.