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Determining Mechanical Reliability of Brittle Materials

Published

Author(s)

Stephen W. Freiman, Jeffrey Fong

Abstract

The widespread existence of slow crack growth in most glasses and ceramics due to a stress-enhanced reaction between an external environment and strained bonds at a crack tip greatly complicates the challenge of assuring the reliability of components which could experience even low levels of stress over a period of time. Water in either liquid or gaseous form is the environment most likely to cause crack growth. Further, because it is the partial pressure of water dissolved in another liquid or present as a gas, rather than its absolute concentration that is important, almost no environment can be considered as absolutely safe. While it has been shown that fracture mechanics expressions can be derived which can predict failure times of brittle materials under such conditions, the uncertainty of these predictions is generally unknown, and can range over many orders of magnitude in time. In this chapter we put forth a description of the testing methodology, analysis techniques, and statistics needed to assure safe operation over specific times, including a discussion of the methods by which the results of laboratory-scale specimens can be used to predict the reliability of a system of parts. We show how advanced statistical methods including the use of three-parameter Weibull models can be applied.
Citation
Handbook of Ceramics, 2nd ed.
Publisher Info
Elsevier, Amsterdam, -1

Keywords

Brittle fracture, error propagation theory, failure prediction, fracture testing, reliability, statistics, tolerance limits, uncertainty quantification, Weibull distribution.

Citation

Freiman, S. and Fong, J. (2013), Determining Mechanical Reliability of Brittle Materials, Handbook of Ceramics, 2nd ed., Elsevier, Amsterdam, -1, [online], https://doi.org/10.1016/B978-0-12-385469-8.00036-8 (Accessed April 16, 2024)
Created April 17, 2013, Updated October 12, 2021