The Study Of Properties For Interface In Composite And Effect Of Moisture On Macro-Properties Of Composite

Composites have the properties of high specific modulus,high specific strength and low cost,which are the advantages that the traditional materials do not possess.Composites have been used widely in a lot of fields,concluding aerospace,building,traffic,mechanics and medicine.The mechanical properties of composite are not only dependent on the material of matrix and fiber,but also dependent on the interfacial bonding mostly.However,the methods of experiment are difficult to determine the mechanical properties of interface for the specificity of it.On the other hand,the theoretical models considered many assumptions or did not consider the effect of interface,which could not represent the reality of composite.Based on the classical shear lag model,bilinear CZM is introduced to represent the mechanical behavior of interface for re-analyzing the transfer mechanism of microscopic stress between interfaces of fiber-reinforced composite materials.The new results of distribution for stress are obtained.We also analyze the effect of different parameters of interface and model on the simulation results,combined with theoretical analysis to explain some phenomena that occurred in single fiber fragmentation experiments.Thereafter,cohesive element is introduced to establish a three-dimensional finite element model that simulates the single fiber fragmentation experiment.The model is built by Python,script of ABAQUS.A new method of estimating interfacial parameters is put forward based on theoretical analysis,the result of FEM and single fiber fragmentation experiment.The FEM results are in good agreement with the theoretical analysis results and the result of experiment.Python program is used to establish signal direction carbon fiber reinforced material model for which the matrix is epoxy resin and fiber are random distribution.The model is used to simulate the diffusion of water in the composite.The result of FEM is compared with the result of experiment.Thereafter,a 2D representative volume element is generated by Python program.Bilinear CZM is introduced to represent the mechanical behavior of interface.The distribution of stress caused by moisture is obtained which is combined with the method of energy to analyze the effect of moisture and interface on the stiffness of composite.This paper can provide some help for understanding the interface of composite and the effect of moisture on composite.On the other hand,it can provide some support for the design of composite...