Size effect on the effective thermal shock strength of porous ceramics with temperature-dependent material properties

Abstract

This work develops a novel numerical micro-discrete model to investigate the size effect on the effective thermal shock strength (TSS) of porous ceramics with irregular and randomly distributed cells. It is observed that the effective TSS increases with the increasing geometric size and reaches a plateau when the size is large enough. The physical mechanisms responsible for that trend are identified. The empirical formula of the effective TSS incorporating geometric size and density is provided. Then the critical thermal load of porous ceramics is calculated. It increases with the increasing geometric size before level out a stable value while decreases gradually with the ascending relative density. And the magnitude will be underestimated around 25% when the temperature-dependent material properties are not considered. The findings provide an efficient approach to predict the integrity and stability of porous materials at elevated temperatures.