Tensile strength and damage of open-cell ceramic foams under cylindrical splitting test

Abstract

To widen the understanding of tensile failure of reticulated ceramic foams and expand the available mechanical method, a cylindrical splitting test is developed in the present study based on alumina open-cell foams of three different pore densities. The biaxial method is validated by characterization of mechanical parameters, and the in-situ fracture process is validated by a digital image correlation, followed by a formula correction for effective tensile strength with consideration of discrete crack paths. For experimental setup curved loading platens, compliant pad and intermediate quasi-static loading rate are proposed for guaranteeing tensile failure under a radial compressive load. Tensile strength, fracture energy, and brittleness increase with the foam pore density, and the fracture behavior is a balanced result of materials and foam structural support strength. An analytical model of splitting tensile strength with structural parameters is derived, which implies its dependence on cell size and critical stress intensity factor of strut materials.

Keywords

• cylindrical splitting test
• mechanical behavior
• structural parameters
• alumina ceramic foams
• digital image correlation