Proposal of a brittle fracture model based on pore and crack interaction effect

The brittle fracture model taking into account of the interaction between pores and cracks is proposed in this paper. The model is applicable to the prediction of tensile strength of graphite materials. In the model, pores are assumed as initial cracks, and cracks are treated by the fracture mechanics method with statistical approach. From comparison between the experimental tensile strength data and the analytical results of the proposed model, it was found that the model predicts not only fairly good the mean tensile strength but also the tensile strength distribution of graphite materials, leading to the validity of the proposed model. Furthermore, it was found that the graphite with larger pore and high porosity is predicted to have a larger pore/grain interaction effect. The grain size dependence on strength is also predicted to have the same trend as the experimental results observed for ordinary ceramics.