Mechanical Failure of Brittle Porous Ceramics

Brittle porous materials used for batteries, fuel cells,  filters, and pharmaceutical applications display a great degree of variability on their  fracture strength and Weibull statistics–limiting a wider use. In this context, finite element simulations was used to rationalize the classical fracture mechanics to quantify the pore-pore stress interactions and  the relationship between the local pore volume fraction and fracture statistics. Simulations show that the maximum reliability of porous ceramics is  limited by the underlying pore–pore interactions. Three different types of deviation from classic Weibull behavior are identified: P-type corresponding to a positive lower tail deviation, N-type corresponding to a negative lower tail deviation, and S-type corresponding to both positive upper and lower tail deviations. Pore-pore interac- tions result in either P-type or N-type deviation in the limit of low porosity, whereas S-type behavior occurs when clusters of low and high fracture strengths coexist in a fracture data.