The influence of Poisson contraction on matrix cracking stress in fiber reinforced ceramics

The influence of Poisson contraction on the stresses for propagating a semi-infinite fiber-bridged crack in unidirectional fiber reinforced ceramics is studied in this paper. The situation of bonded fibers that is subjected to compressive pressure due to thermal expansion mismatch between the fiber and the matrix is considered in the present analysis. The results show that the Poisson contraction has profound effects on the matrix cracking stress predictions in the ceramic matrix composites, especially for the composites with high coefficient of friction. The Poisson contraction effects can be evidenced by the comparison of the present analysis with the Aveston, Cooper and Kelly (ACK) model. The roles played by the interfacial properties of the interfacial bonding energy and the coefficient of friction on the stresses for matrix cracking are discussed.