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Crack Propagation in Laminar Ceramics
Last modified: 2013-03-15
Abstract
The contribution presented deals with crack propagation in ceramiclaminates. Assumptions of linear elastic fracture mechanics and small scale yieldingare considered. The crack behaviour in ceramic laminate body under external loadingis investigated. Strong residual stresses due to different coefficients of thermalexpansion of individual material layers are taking into account in finite elementcalculations. The change of crack propagation direction on material interface isestimated on the base of strain energy density and maximum tangential stress criteria.The influence of thickness of laminate layers on crack propagation direction isestimated. The stepwise crack propagation path of the crack propagating throughAl2O3-ZrO2 ceramic laminate is numerically estimated. The comparison of estimatedcrack path with experimental data is done and mutual good agreement is found. Theresistance to crack propagation through laminate body depends on the level of crackdeflection on material interfaces, thus the estimation of the crack propagation directionor generally of the crack path is necessary for determination of so-called apparentfracture toughness of the laminate. The procedure suggested can contribute toenhancing of reliability of structural ceramics or generally of layered composites withstrong interfaces.
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