Experimentally investigating the effect of viscoelastic joint of a cantilever beam containing piezoelectric patch on the harvested energy

Abstract

The purpose of this study was to examine the effect of the connecting beam to the main structure considering the viscoelastic property, which affects the rate of electrical energy harvested from the piezoelectric patch connected to the aluminum beam. In this research, the connection of the beam to the vibrator was considered viscoelastic to obtain more accurate results. Viscoelastic material decreases the amount of stress and strain along the beam as well as the piezoelectric path due to its softness; thus, less potential difference is expected to be produced than the rigid connection. First, the beam is deformed by a base harmonic excitation on the beam containing the piezoelectric path, which generates an electric potential difference on both sides of the piezoelectric. In this study, the behavior of an aluminum beam with a piezoelectric patch and viscoelastic connection under loading and excitation of the harmonic base is examined based on experimental testing and 3D finite analysis. The experiment was performed by connecting an aluminum beam to a vibrator rotating unbalance system to create a harmonic base excitation under the connection of viscoelastic adhesive and rigid connection of bolts and nuts. The finite element method was used for numerical solution by Ansys software. The piezoelectric patch used in this analysis was of 5A type with two piezoelectric layers and a brass layer. Viscoelastic simulation was modeled in the 3D form using a special viscoelastic element in an Ansys environment. In order to solve the harmonic problem, the loading was considered as the base excitation with input acceleration. The diagrams of the electric potential difference revealed that the amount of energy harvested from the viscoelastic joint was less than that from the rigid joint. In addition, modeling of the viscoelastic joint by the Kelvin–Voigt and the Maxwell mechanical model shows that the results of these two joint models are more consistent with the result obtained by the standard solid joint. Electrical power diagrams were drawn considering different resistances. It is obvious that the amount of harvested power increased with increasing input frequency. Finally, the results of 3D finite element analysis were compared to the results of energy harvesting experimentally for verification.