Abstract
Porous ceramics is basically categorized as brittle material. However, it shows a little nonlinear stress-strain behavior and has damage tolerance. To evaluate the extent of damage tolerance of porous ceramic, we have proposed the distributed-micro-crack model and applied it to nonlinear stress-strain behavior analysis of porous ceramics. In the previous studies, the distribution of initial crack sizes was not considered in the model. Though the model without initial crack size distribution can predict the initial stage of deformation (i.e. quasi linear stress-strain region) of porous ceramics, it can't evaluate the final stage of deformation near fracture. It can be considered that this discrepancy is due to the localized damage mechanism that can't be estimated by the model without initial crack size distribution. Therefore, initial crack size distribution is introduced into the model in present studies. In this paper, results from analyses by the modified distributed-micro-crack model with initial crack size distribution are presented. Weibull distribution is employed as the initial crack size distribution profile. It is concluded that this modification can simulate localized damage and not only initial stage of stress-strain relationship but also near fracture stage of it obtained by the model shows good agreement with experimental data.
