Fracture Toughness Model of Fiber Reinforced Ceramics
This paper addresses the fracture resistance mechanism in fiber reinforced ceramics, and focuses attention on the specific effects associated with the nonlinear nature of the fiber pullout mechanism. The model is based on a consideration of the representative boundary value problem typical for the bridging process. The theoretical solution includes an accurate account of the nonlinear fiber matrix friction. An explicit incorporation into the analysis of a discrite fiber distribution and formulation of an exact solution to the corresponding problem are distinck features of this model. The developed approach allows consideration of several types of nonlinear fiber pullout - force dependence. The distinct features of the nonlinear process demonstrate that, contrary to the linear case, the universal fracture resistance curves cannot be developed in cases with significant nonlinear contribution in the fiber friction law. The resulting resistance curves strongly depend on the absolute values of the matrix fracture toughness. On the other hand, these distinct patterns may be used for identification of the particular friction law and determination of the friction parameters.