Dependences of Mechanical Properties of Ceramics with Bimodal Pore Size Distribution on the Porosity at Various Scale Levels

Resumo

Peculiarities in the dependences of the elastic and strength properties of ceramics with a hierarchically organized pore structure on the porosity are revealed. To exclude the influence of other microstructural factors, such as, for example, grain size, the study was carried out on the basis of multilevel computer modeling using movable cellular automata and a probabilistic approach. A special computer model of the mechanical behavior of porous ceramics with a bimodal pore size distribution has been developed. At the lower level of the model, small isolated pores are explicitly taken into account and series of calculations are carried out for the representative samples with individual pore arrangement in space. The values of the elastic and strength characteristics of these samples obtained as a result of Weibull analysis serve as effective properties of the porous material matrix at the mesoscale. At the mesoscale, large pores of both equiaxial and elongated shapes are considered explicitly. At the macrolevel, the heterogeneity of the material is described implicitly by setting to the automata the unique elastic and strength properties obtained from the Weibull analysis of the calculation results obtained at the mesoscale.