Analytical solution for an arbitrarily oriented void crack and fracture ofpiezoceramics

The solutions for a piezoelectric plane with an arbitrarily oriented ellipt ical void and a crack are derived by the method of extended Lekhnitskii's f ormalism. Analytical solutions are obtained for all electroelastic field Va riables around the Void and at the crack tip. The generalized solutions pre sented in this study can be reduced to the results reported in the literatu re for special cases of defect orientation, i.e. defects parallel or perpen dicular to the poling direction. It is found that the effect of defect orie ntation 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 dire ction 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 di rection, and a negative one tends to close a crack except for the crack par allel to the poling direction. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.