Cavity defects and failure study of ceramic components

摘要

Failure of brittle materials like ceramics is discussed along with computational analysis techniques. Damage by cracking on the microscopic scale is investigated by a model based on the material structure. The progression of damage and the failure mode - quasi-brittle or brittle - are seen to be sensitive to the material structure and the loading. On the continuum level statistical test data are utilized in order to estimate the variation in material strength within structural components. Results from stress analysis combined with repeated sampling of the random strength distribution in the finite element mesh estimate the potential of single locations to initiate failure. Assessment of the survival probability relies on the Weibull approach. The formalism for structural components implies evaluation of the stress volume integral by simple post-processing in finite element stress analysis. Adaptive mesh modification may be based on an error criterion proposed in terms of the stress volume integral. It considers the statistical characteristics of the brittle material, and has been found to perform well.