In recent years, the functions of porous ceramics have been paid high attention. Porous ceramics have advantages of porous materials and advantages of ceramics simultaneously, such as high strength, high elastic modulus, high corrosion resistance, high thermal resistance. The mechanical properties of porous ceramics have come to occupy an important position in application. Various reports have been published on the mechanical properties of foams(porosity above than 70%) over a long period of time. However, No complete interpretation about typical porous ceramics(porosity below than 70%) has been formulated and it seems to be a worthwhile subject to investigate.
The mechanical properties of porous ceramics with the controlled pore design were investigated through experiments and numerical analysis. Elastic modulus changes with different pore structure and pore shape were calculated by using finite element method(FEM). Porous ceramics containing well-defined pore structure and shape were prepared by incorporation of fugitive additives into alumina and incomplete sintering of silica. Processing variables provide various microstructure and the amount of porosity as well. Elastic modulus was evaluated by the impulse excitation of vibration method.
Effect of pore structure on elastic modulus was investigated. Elastic modulus of the inter-connected pore structure was more sensitive to porosity than that of the isolated pore structure and open porosity/closed porosity ratio could be used to predict elastic modulus. Effect of pore shape on elastic modulus was examined. It was found that elastic modulus changed as loading condition and pore shape changed. Semi-empirical equation was derived from FEM results in order to predict elastic modulus with aspect ratio of ellipsoidal pores. Finite element analysis was confirmed as a useful tool to simulate the effect of pore structure and shape on the mechanical properties of porous ceramics.
