Identification of a damage criterion of a highly porous alumina ceramic
Résumé
This paper aims at identifying the multiaxial compression behavior of highly porous ceramics used as
catalyst supports. For this purpose, instrumented spherical indentation tests are performed, together
with uniaxial and hydrostatic compression tests. A transition from a brittle to a damageable behavior
with densification of the material is noted when increasing the triaxiality of the test. The collapse of large
pores is shown as being responsible for the densification phenomenon, as confirmed by SEM and
mercury intrusion porosimetry. A multiaxial damage criterion is proposed and identified thanks to a
numerical finite element model.
The results described in this paper coupled with a previous work (Staub et al., Oil and gas science and
technology 2015, vol 70, n 3, 475e86) on the behavior of the same material under tension loading, allow
for the first time to define a multiaxial criterion both in tension and in compression for highly porous
ceramics. These materials are shown to present a typical behavior of dense ceramics in tension, whereas
in compression, their behavior is close to that of porous rocks.