Digital Repository, ICF12, Ottawa 2009

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Cohesive zone model for intergranular environmental and stress assisted failure and analysis of slow crack growth in ceramic polycrystals
M. Romero de la Osa, R. Estevez, C. Olagnon, J. Chevalier, C. Tallaron

Last modified: 2013-05-03


Ceramic polycrystals are prone to environmentally assisted Slow Crack Growth
(SCG), similarly to vitreous glasses. The kinetics of fracture is known to be
dependent on the load level, the temperature and also on the Relative Humidity
(RH). In addition, there are evidences that the microstructure influences SCG with
an increase in the crack velocity when varying the grain size. This latter
observation motivates a local description of fracture with a cohesive zone model
for the intergranular failure process. A rate and temperature dependent
formulation is proposed to mimic the reaction-rupture mechanism underlying
failure. We indicate how the parameters involved in the description can be
determined from experiments. We present 2D simulations of intergranular
fracture and study the influence of a strong junction or the presence of pores or
poor cohesion properties at the triple connection of grains on SCG.

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