Shear mode of the converse piezoelectric effect

For sensor applications, use is made of the direct piezoelectric effect and thus the piezoelectric cube described above now has to be subjected to mechanical fields. Strains and stresses are applied via associated surfaces either by prescribed displacements in a clamped configuration or by applied forces in a free configuration. Besides the intended sensor application, this, of corrse, is also relevant to the case of solely passive transmission of loads. Consequently, the subsequent examinations are also important for the general application of electromechanically coupled materials in adaptive structures. For mechanical fields operating opposed or transverse to the polarization direction, the field levels are limited by the risk of repolarization similar to the actuation case. 

When the electrodes on the associated surfaces are connected, only the particular electric flux density component shows a constant non-zero distribution with opposed orientation. Charges cannot accumulate on the electrodes as they flow off instantaneously. For a dynamic process, this flow of charges may be determined by a current measurement, and is proportional to the strain rate, respectively stress rate. From the energetic point of view, the charge compensation must also have consequences for the mechanical fields. This becomes apparent by reorganization of the constitutive relation for these conditions and is reflected in the dissimilar stiffness and compliance matrices of Eqs. (4.10a) and (4.10b). These influences may be summarized for the basic load cases with resulting electrostatic fields in g-direction  

These switchable properties may be used to tune the frequency response of a structure, for example, when eigenfrequencies need to be avoided during the run-up of rotating machinery. Furthermore, the coimection of electrodes via resistors or inductors permits the damping or insulation of vibrations by 

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