Multiple parallel cracks interaction problem in piezoelectric ceramics

This paper has two goals. First, we propose the 'pseudo-traction-electric d isplacement' method for solving the interaction problem of multiple paralle l cracks in transversely isotropic piezoelectric ceramics. Second, we prese nt a fundamental understanding for the role that the electric displacement loading plays in the interaction problem. Detailed comparisons between the results under the compound mechanical-electric loading conditions and those derived under purely mechanical loading conditions are performed. It is sh own that the mechanical fracture parameters such as the stress intensity fa ctors are no longer independent of the electric loading as they would be in single crack problems. Quite contrary, the electric displacement loading h as a significant influence on the stress intensity factors, the total poten tial energy release rate and the mechanical strain energy release rate. Thi s important conclusion is mainly due to the interaction effect, i.e., one o f the multiple cracks releases the stresses and disturbs the electric field s near the other crack. It is also found that there are some special relati ve locations for the multiple parallel cracks at which the electric displac ement loading has no effect on the Mode I stress intensity factor. However, the mechanical strain energy release rate has no such a property. (C) 1999 Elsevier Science Ltd. All rights reserved.