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The paper demonstrates the possibility of controlling the dissipative properties of structures containing viscoelastic elements by adding piezoelectric elements, to the electrodes of which external electrical circuits are connected. On the basis of the results of solution to the problem of natural vibrations of piecewise-homogeneous electro-viscoelastic bodies with passive external electric circuits, an analysis of the effect of a shunted piezoelectric element on the damping coefficients of an electro-viscoelastic system was carried out. A two-layer shell structure is adopted as the object of research. The outer layer of the shell is made of elastic, and the inner one is made of viscoelastic materials. For the case of attaching resistive-shunted piezoelectric element it was shown that a resulting damping coefficient for the specified vibration mode is not a simple algebraic sum of damping coefficient obtained for a viscoelastic structure without piezoelectric element and the one obtained for an elastic structure with resistive-shunted piezoelectric element (in case when resistance of a shunting circuit is optimally chosen). At the same time, an attention is drawn to the fact that if the damping coefficient of the corresponding vibration mode decreases when only a piezoelectric element is connected, then even when a resistive circuit with optimal parameters is connected to it, the final damping coefficient for this vibration mode may be lower than that of a structure without a piezoelectric element. [ABSTRACT FROM AUTHOR]

The paper is devoted to investigation of mechanical response of an electro-viscoelastic structure (a structure with piezoelectric element attached to its surface) in case when electric voltage with prescribed parameters is applied to electrodes of piezoelectric element. A cantilever plate was considered as such a structure. An amplitude of displacements of the free end of the plate at resonant modes is considered as a mechanical response in case when forced steady-state vibrations occurring under kinematic or force loading are considered. Mechanical response of the structure is determined numerically using the ANSYS software package. Viscoelastic properties of a material of the plate are taken into account using the model with complex dynamic moduli. Within the frameworks of this paper relations between mechanical response of the structure and magnitude and polarity of electric voltage applied to electrodes of a piezoelectric element was obtained with respect to a type of excitation of vibrations. [ABSTRACT FROM AUTHOR]