The Use of a Shunted Piezoelectric Element to Ensure the Best Dissipative Characteristics of Viscoelastic Shells

The paper studies the dependence of the dynamic characteristics of an electro-viscoelastic system, which is a piecewise homogeneous body consisting of elastic, viscoelastic, electroelastic (piezoelectric) elements, as well as external passive electrical circuits attached to the electroded surfaces of piezoelectric elements, on the parameters determining its geometric configuration (dimensions and location of viscoelastic and piezoelectric elements, forming the system, in relation to structure and each other). In these systems, two methods of energy dissipation are used to reduce vibration: internal friction in viscoelastic materials and the conversion of mechanical vibration energy into electrical energy which is then dissipated in electrical circuits. Resistive (R) and resonant (RL) circuits are considered as examples of external electrical circuits. The study was conducted based on a numerical solution to the natural vibration problem for a thin-walled, spatial structure having the form of a semi-cylindrical shell. All possible geometrical configurations for the arrangement of viscoelastic and piezoelectric components were considered. There were found designs that could provide optimal damping properties within a specific frequency range, either via internal friction or by converting vibration energy using a piezoelectric component. As a result of a series of computational experiments, we obtained quantitative estimates demonstrating how the damping properties of the system change when each of the considered vibration energy dissipation mechanisms is used separately or jointly. The obtained quantitative estimates of changes in the dissipative properties of the shell show, in which cases both energy dissipation mechanisms lead to an increase in the damping characteristics of electro-viscoelastic systems, and in which cases they lead to a decrease.