The solutions for a piezoelectric plane with an arbitrarily oriented elliptical void and a crack are derived by the method of extended Lekhnitskii's formalism. Analytical solutions are obtained for all electroelastic field Variables around the Void and at the crack tip. The generalized solutions presented in this study can be reduced to the results reported in the literature for special cases of defect orientation, i.e. defects parallel or perpendicular to the poling direction. It is found that the effect of defect orientation on the electroelastic fields around a void and at the crack tip is rather subtle. Solutions for defects oriented parallel or perpendicular to polarization cannot be always considered as the critical case. A change of crack orientation may alter the trend of toughness variation, and initiate failure along different planes or cause crack closure depending on the direction of electrical field and ratio of electrical to mechanical loading. It is shown that a positive electric held may retard or enhance crack growth depending on the orientation of a crack with respect to the polarization direction, and a negative one tends to close a crack except for the crack parallel to the poling direction. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. References: 18
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