Research On The Relationship Between Microstructure And Mechanical Properties Of The 3D Woven Composites

Scantling size maximization,structure complication and lightweight is the development trend of composites in the field of aerospace and national defense.The 3D Composite Flexible Woven(3D-CFW)technique offers a method to some technical problems,such as the 3D woven and Z-reinforcement of complex variable-section parts,which is quite necessary for the realization of composites flexible 3D woven,and for the study of the microstructure model of 3D woven composites and the effect of material performance.In this paper,by the methods of structural modeling,finite element model and experimental test,the relation between microstructure and macro mechanics is builded.The mechanical performance of structure is predicted by the basic performance of component material.Furthermore,the integration of microstructure design and mechanical performance design is realized,and theoretical support is offered to the engineering application of composites 3D woven technique.The relation between the microstructure model of 3D woven composites and mechanical performance is studied in this paper.Composites microstructure model with loop curve and eight-shape curve weaving paths is builded innovatively,and the relationship of fiber volume fraction and micro model structure parameters is builded.The error between theoretical calculated value and the experimental value is less than 5%.The effect of weaving path and structure parameters on fiber volume fraction is studied.The study shows that,when the radius of guide sleeve is 1mm and the center distance of sleeves is 6mm,the fiber volume fraction of prefabricated part by curve ring weaving path is greater,and 34.71%could be reached.Aim at the problems of being difficult to predict the mechanical performance of 3D woven composites,which is due to material components,weaving path and several variable loads,the finite element analyzing model of micro structure model of 3D woven composites is builded innovatively,and macro mechanical performance of 3D woven composites could be predicted effectively.By elastic modulus and poisson's ratio experimental tests of different weaving paths and structure parameters,the accuracy of finite element analyzing model is further validated,and it could be used for the prediction of elastic performance of 3D woven composites.On the basis of the study of 3D woven composites micro structure model and finite element analyzing model,the effect rule of different weaving paths and structure parameters on the in-plane mechanical performance and Z-direction mechanical performance of composites is further studied.The structure parameters and weaving path of better in-plane mechanical performance and Z-direction mechanical performance are studied,and the failure mode and the failure mechanism of 3D woven composites are analyzed.