Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7178220 | Journal of the Mechanics and Physics of Solids | 2014 | 29 Pages |
Abstract
In brittle polycrystalline materials, anisotropic shape changes-such as those due to thermal expansion, composition changes, and piezoelectricity-can induce stresses severe enough to drive fracture. The stresses developed are microstructurally heterogeneous and develop in proportion to a generalized external stimulus rather than an applied load; as a consequence, traditional Weibull models do not capture the relevant scaling of failure probabilities with respect to applied stimulus or microstructural feature sizes. These limitations are surmounted by a stochastic method, called Finite Element plus Monte Carlo (FE+MC), which enables quantification of reliability statistics in brittle polycrystalline materials subjected to microstructurally heterogeneous stresses which may be driven by non-mechanical stimulii. A finite element analysis computes the stress distributions for a hypothetical defect-free virtual microstructure and a subsequent Monte Carlo analysis distributes flaws throughout the microstructure with sizes chosen from an experimental flaw size distribution. The FE+MC method is validated for uniaxial tensile loading, for which the expected Weibull distribution of failure probability is reproduced. As a demonstration of the utility of this method in a more complex stress state, we consider electrochemical shock of polycrystalline LiXCoO2 electrodes; the computed composition-dependent failure probabilities reproduce key features of experimental acoustic emission measurements not explained by previous modeling approaches.
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Physical Sciences and Engineering
Engineering
Mechanical Engineering
Authors
William H. Woodford, Yet-Ming Chiang, W. Craig Carter,