Characterisation of mechanical properties of cellular ceramic materials using X-Ray computed tomography

Abstract

Carbon foams are refractory cellular materials. The material exhibits an open porosity with a tridimensional architecture offering multifunctional properties. These properties can ever be tailored threw post processing in order to use the material in many fields such as energy (fuel cell) or transport (shock absorber). For all applications, the knowledge of the mechanical properties is important. These properties depend on the 3D architecture and the damage kinetics. In this study the computed X-Ray microtomography (μCT) has been used firstly to analyze the damage kinetics during in-situ compression tests and secondly to simulate the behavior. The µCT compression tests lead to the local damages and global deformations. The analyses of these images will be presented to illustrate the potentiality of tomographic investigations for brittle cellular materials. To assess both the stress and strain fields, a model based on the real material was developed. This model consists in meshing the tridimensional images and modeling the behavior of the constitutive material. The fracture of cells is treated using an adapted law and a brittle criterion. The models are also compared with the measured macroscopic mechanical behavior or adapted to simulate numerically-generated materials.