An interface electrode between two piezoelectric layers

An interface electrode in a bi-layer piezoelectric medium is investigated. Closed-form expressions for the electromechanical fields at the electrode tip are obtained as functions of the applied electric field intensity factor. The values of the electric field intensity factors are obtained exactly for infinite layer thickness and numerically for finite layer thickness. Effect of the layer thickness to electrode length ratio on the stress, electric displacement, and electric field are graphically shown. Energy density theory is used to analyze the crack initiation behavior near the electrode tip. It is found that the stresses, field intensities, and the energy densities at the electrode tip can be reduced significantly by reducing the thickness of the piezoelectric layer. In addition to the single interface electrode, the problem of two identical and collinear interface electrodes is also investigated. Relative distance between the electrodes is observed to have considerable influence on the electromechanical field near the electrode tip in the piezoelectric layer. (C) 2008 Elsevier Ltd. All rights reserved.