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Proceedings Paper

Nonlinear fracture mechanics of piezoelectric ceramics
Author(s): Chandler C. Fulton; Huajian Gao
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Paper Abstract

The reliable performance of piezoelectric ceramics in smart structures is hampered by the propagation of cracks from microflaws in the devices. Discrepancies between experimental and analytical results indicate that the established linear theory is insufficient to characterize the cracking behavior of these materials. In fact, the direct extension of linear elastic fracture mechanics to coupled electromechanical problems cannot even reproduce the overall trends observed in the laboratory. In the interest of developing a fundamental understanding of piezoelectric fracture, we present a physics-based analytical model which accounts for nonlinear material response to applied electric fields. By adopting a multiscale viewpoint, the mechanical and electrical singularities at the crack trip are separated. At the local length scale, nonlinear electrical behavior is explained in terms of the effects of discrete electric dipoles, and the crack driving force is altered by the resulting interaction forces. A closed-form expression is obtained for the local energy release rate, which is independent of the exact distribution of dipoles. The model is general enough to account for arbitrary material anisotropy and crystal orientation, for any mechanical or electrical mode of cracking. Analytical predictions of the dependence of fracture stress on applied electric field agree qualitatively with empirical observations in cases for which experimental data are available.

Paper Details

Date Published: 24 July 1998
PDF: 9 pages
Proc. SPIE 3323, Smart Structures and Materials 1998: Mathematics and Control in Smart Structures, (24 July 1998); doi: 10.1117/12.316292
Show Author Affiliations
Chandler C. Fulton, Stanford Univ. (United States)
Huajian Gao, Stanford Univ. (United States)

Published in SPIE Proceedings Vol. 3323:
Smart Structures and Materials 1998: Mathematics and Control in Smart Structures
Vasundara V. Varadan, Editor(s)

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