Study On Modeling And Properties Of New Lightweight Ceramic Matrix Composites

Ceramic matrix composites are widely used in energy environmental protection,aerospace and biomedical fields due to their excellent high temperature resistance,thermal stability and low density.With the improvement of the preparation process,the original brittleness of the material has been reduced,but due to the purity of the prepared raw materials,the stability of the preparation environment and the external force factors in the use process,the material may have microscopic defects,causing significant losses in practical applications.Therefore,it is necessary to study the impact of defects on performance.In this paper,a new type of lightweight ceramic matrix composites is studied,and the modeling and analysis methods of materials are studied to obtain the influence of microscopic defects on material properties.The specific research content is divided into the following three aspects:According to the microscopic characteristics of the new lightweight ceramic matrix composites,this paper uses scanning electron microscopy and particle size analysis software to scan and analyze the structure and composition of the internal fibers of the material,by calculating the porosity of the material and Density to determine the type of material.The fiber orientation of the electron microscopy images was statistically analyzed by image processing.The results showed that the fibers in the in-plane direction had no obvious orientation,and the fiber orientation in the cross-section direction was normally distributed.The orientation characteristics of the fibers were consistent with the distribution of anisotropic laminates.For complex internal structures,the finite element model is established by ANSYS Workbench software,and the basic thermal performance of the material is analyzed according to the simulation model data.Applying external force in the vertical direction of the model and observing the degree of fiber deformation,the material has the ability to effectively relieve the impact of external force in this direction,and at the same time verify the relationship between the elastic modulus of the material and the porosity and internal fiber diameter.The gap between the fibers of the material reduces the overall thermal conductivity,and the material organic matter decomposes and absorbs heat under high temperature conditions to reduce the heat transferred inside the material,thereby achieving the overall heat insulation effect.3)For the fiber model with defects after the external force is loaded,the CT scanning technology is used to detect the internal defects of the fiber model,combined with the defect detection results and using the finite element simulation method for the transverse fiber break defects and longitudinal fiber break defects.The finite element model is studied and analyzed,indicating that the fracture is more likely to occur when the load is applied in the in-plane direction.In addition,when the material is at a high temperature of 10000 C,the organic matter is thermally decomposed,thereby causing a decrease in the overall strength of the material.Therefore,the research work in this paper is of great significance for the study of the effects of defects in porous laminate materials.