Multi-Scale Analysis Of Hole Edge Stress In Plain Weave Ceramic Matrix Composites

The plain weave ceramic matrix composite material overcomes the shortcomings of the brittleness of conventional ceramics,and it has reliability at high temperatures,as well as corrosion resistance and wear resistance.It is used for hot end parts of aerospace vehicles and has good application prospects.The research on its mechanical behavior has important engineering significance and value.In this paper,experiments and numerical analysis are carried out for the damage characterization,stress concentration at the hole edge,and meso-level simulation of mechanical properties of plain weave ceramic matrix composites.The acoustic emission characteristics of the ceramic matrix composite during the stretching process were monitored.Based on the principal component analysis method and K-means cluster analysis method,the acoustic emission signal is clustered.The acoustic emission signal is classified from the energy point of view,and matched with the type of damage and failure during the stretching process.The ARAMIS digital speckle strain measurement system was used to test the strain field around the hole of the plain weave ceramic matrix composite.The effect of the hole diameter on the tensile strength of the hole-containing specimen was experimentally studied.The strain change law in different areas of the cross-section of the via was explored.Combined with the non-porous plate,the true stress curve of the cross-section of the via is obtained.Through the unit cell model,the influence of random fiber distribution on the properties of composite materials is discussed,and the mechanical properties of the previous scale are predicted.The subroutine is used to define the material damage and failure criteria,and the finite element results are compared with the test results and the integrity is better.Through the finite element model,the influence of the opening position and opening size of the plain weave structure on the stress distribution is analyzed.The results show that the stress is mainly concentrated on the fiber bundles near the opening.Different opening positions show obvious differences,and the double cross-shaped opening has the greatest impact on the stress of the material.And not all plain weave structures have a smaller opening diameter,the higher their safety.