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Proceedings Paper

Multiscale energy release rates in fracture of piezoelectric ceramics
Author(s): Huajian Gao; Chandler C. Fulton; Tong-Yi Zhang; Pin Tong; David M. Barnett
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Paper Abstract

The reliable use of piezoelectric ceramics as actuators in smart structures hinges on a fundamental understanding of the fracture process in these materials. However, despite the success of fracture mechanics theories in explaining the cracking behavior of a wide range of engineering materials, the extension of these accepted criteria to piezoelectrics fails to predict even qualitatively their response to combined electrical and mechanical loads. A new fracture criterion is presented here, in which a multiscale point of view is adopted in order to account for a zone of combined mechanical brittleness and electrical ductility near the crack tip. As a starting point for the investigations, we assume that the region of electrical nonlinearity is confined to aline segment ahead of the crack, analogous to the Dugdatle zone of plasticity in metals. This mathematical simplification represents the physical situation in which a distribution of excess electric dipoles is aligned on a finite segment in an otherwise linear piezoelectric solid. By applying this model to both insulated and conducting cracks subjected to far-field loading, we obtain local-scale energy release rates whose dependence on applied tractions and electric fields agrees with the trends observed experimentally. One important feature of the analytical expressions for crack driving force is that they are independent of the strength and size of the nonlinear zone.

Paper Details

Date Published: 13 June 1997
PDF: 6 pages
Proc. SPIE 3039, Smart Structures and Materials 1997: Mathematics and Control in Smart Structures, (13 June 1997); doi: 10.1117/12.276541
Show Author Affiliations
Huajian Gao, Stanford Univ. (United States)
Chandler C. Fulton, Stanford Univ. (United States)
Tong-Yi Zhang, Hong Kong Univ. of Science and Technology (Hong Kong)
Pin Tong, Hong Kong Univ. of Science and Technology (Hong Kong)
David M. Barnett, Stanford Univ. (United States)

Published in SPIE Proceedings Vol. 3039:
Smart Structures and Materials 1997: Mathematics and Control in Smart Structures
Vasundara V. Varadan; Jagdish Chandra, Editor(s)

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