A new approach to the subcritical propagation of cracks in ceramics

Martin Genet (1) , Pierre Ladevèze (1, 2)

1 LMT - Laboratoire de Mécanique et Technologie
2 EADS Foundation Chair Advanced Computational Structural Mechanics

A new modeling approach to subcritical crack propagation (i.e. static fatigue) in ceramics has recently been introduced [9] and applied to the case of ceramic fibers. This approach relies on classical fracture mechanics, in which the zone near the crack's tip is modified by the environment (particularly through oxidation, corrosion, etc). In some cases, it comes down to the widely-used three-parameters Paris-like subcritical crack propagation law. For the general case, a two-parameter propagation law is derived that only depends on the total oxygen flux reacting at the crack's tip. Consequently, this model is valid for any temperature, oxygen or water pressure, etc, which can vary along time, as long as the environment is modelled properly. For Hi-Nicalon fibers up to 1000°C in dry atmosphere, the chemical phenomena observed are introduced through simple diffusion/reaction models in order to define the true oxygen flux reacting at the crack's tip. The resulting identified model is validated on experimental data.

Domaines: Mécanique des matériaux [physics.class-ph]

Martin Genet, Pierre Ladevèze. A new approach to the subcritical propagation of cracks in ceramics. 14th European Conference on Composites Materials (ECCM14), Jun 2010, Budapest, Hungary. ⟨hal-01274841⟩