Research On Mechanical Performance And The Dispersion Of Ceramic Composites With Porosity

Carbon fiber reinforced Silicon carbide ceramic matrix composites are promising candidates foraerospace and aircraft thermo-structural components, which has been the emphasis of compositeresearch. However, the research of both unidirectional and2.5D woven ceramic matrix composites atits beginning stage, and most models of the composite are simple to simplify problems. To make surethe reliable use of ceramic composites on actual components, it is necessary to perform theinvestigation on the mechanical and failure behavior of C/SiC ceramic composites.The methods for predicting the elastic properties of micro-scale model are proposed，includingstiffness average method, Mori-Tanaka and finite element method. The elastic properties of2.5Dwoven ceramic matrix composites were predicted by using unit cell for the composite, the resultsagreed well with the experimental data, and the parametric study also demonstrates that porosity havegreat effect on the result. Finally, the dispersion of the elastic modules was studied throughMonto-Carlo method.Based on analytical model and finite element method of unidirectional composites, the thermalexpansion coefficient and the thermal conductivity coefficient for2.5D woven ceramic matrixcomposites are calculated, the results are compared with the experimental data, and the dispersion ofthe thermal expansion coefficient and the thermal conductivity coefficient were also studied. Finally,Due to the models are complex, the simulation and analysis system software of2.5D woven ceramicmatrix composites has been designed and developed. The system has the clear interface management,powerful performance of human-computer interaction, which enhances practical application value ofceramic matrix composites.The nonlinear spring element method for the interface and the new micromechanical method areemployed to predict the stress–strain curve and fracture behaviour of ceramic matrix composites, themethods considered the interfacial bonding in composites. Finally, an approach to predict thestress–strain curve of2.5D woven ceramic matrix composites by stiffnes reduction model has beenproposed. The results show that the theoretical results can fit the experimental results well and thetheoretical method is validity.