Shear mode of the direct piezoelectric effect

For the typical applications of piezoelectric materials, simplifying assumptions with respect to the mechanical and electrostatic fields are reasonable. These may be introduced in consequence of the spatial extent and electroding of the considered structure and, namely, are assumptions of planar mechanical and unidirectional electrostatic fields. Thereby, the variants of the latter, although 

For the intended normal mode actuation or sensing with electrodes responsible for the polarization direction, the latter case is practically not possible, while the prior needs to be further examined. The complications considered in 

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