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Single and Double Deflections of Cracks at the Carbon‐Carbon/BN Coating Interfaces in Ceramic‐Matrix Composites
Author(s) -
Kumar Susmit,
Singh Raj N.
Publication year - 1998
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1998.tb02486.x
Subject(s) - materials science , composite material , deflection (physics) , boron nitride , penetration (warfare) , strain energy release rate , finite element method , coating , ceramic , ceramic matrix composite , fracture mechanics , composite number , structural engineering , physics , operations research , optics , engineering
A finite element technique is used to study the effects of coating properties on the deflection and penetration of cracks which terminate perpendicular to the bimaterial interfaces in SCS6‐zircon composites having three coatings (two carbon coatings and one boron nitride) on the fibers. Although, the change in the thickness of coatings has a very small effect on the stress ratio (ratio of hoop stresses along a crack and at the interface) and the energy release rate ratio (ratio of energy release rates for crack penetration and crack deflection), the magnitudes of the stresses and energy release rates change substantially. The finite element results are compared with experimental observations of Kumaria et al. on the nature of crack propagation behavior in these composites. Our finite element results explained the evidence of the doubly deflected cracks at the carbon‐carbon interface as experimentally seen by Kumaria et al.