Porous microcracked ceramics under compression: Micromechanical model of non-linear behavior

Stress-strain curves for porous microcracked ceramics (such as aluminum titanate) under compression exhibit non-linearity, hysteresis, and a sharp increase in stiffness when changing from loading to unloading. A micromechanical model is developed that expresses these features in terms of porosity and crack density. The mentioned features are linked, in a quantitative way, to closures and frictional sliding of microcracks. The model also allows one to extract information on crack densities from stress-strain curves, which provides insight into the evolution of open, closed and sliding cracks. The model is approximate due to uncertainty factors, but its predictions are generally in agreement with the data and the information conveyed by SEM images. (C) 2013 Elsevier Ltd. All rights reserved.