Analyzing On The Influence Of Interface On Mechanical Capabilities Of Ceramic Matrix Composites

Ceramic Matrix Composites(CMC) has excellente capabilities such as high strength, high rigidity, high elastic modulus and good chemical stabilization and was considered as the perfect high temperature structural material to be used on the aero engine of which the ratio of thrust to weight is high than 10. As the interface is one of the most important part of CMC, the structural characteristic, mechanical capabilities and damage rules may directerly affect the whole capabilities of the material. So it's meaningful to investigate CMC's structural, mechanical properties and damage rules.The research work of this paper is mainly including following:(1)The stress distribution of the RVE which with or without an interphase and the effect of the interface properties on RVE in the two conditions based on the shear-lag model are analyzed.The results indicate that the stress distribution of the RVE is influenced by the elastic modulus, volume fraction and the Poisson's ratio of the interphase.(2)The stress distribution of the thermal residual stress of the RVE that caused during material producing is further considered and two conditions of the RVE that with or without the interphase are compared.The results indicate that besides the interphase properties, the thermal expansion coefficient also has distinct influence on the stress distribution of the RVE and these two factors should be considered during material designing.(3)Fiber, matrix and interface criterions are used to model the progressive damage of CMC. The effects of the interface properties on the stress-strain curves of CMC are also analyzed. The results indicate that increasing elastic modulus and interphase volume fraction is helpful for material bearing the stress and increasing the Poisson's ratio and interface shear stress are helpful for preventing material fail catastrophically.