Finite-element modelling of piezoelectric energy storage device based on cantilever

Simulating a piezoelectric generator which is an element of the energy storage device is considered. A piezoelectric generator appears a cantilever-mounted plate on which the piezoelectric elements are glued, and the inertial mass is attached. Two options of the plate vibration excitation are investigated. In the first case, the fixed side executes heave harmonic motions at a given frequency and with the desired amplitude; in the second - a harmonic force is applied to this side. A three-dimensional boundary-value problem of the linear theory of electroelasticity for the composite elastic and piezoelectric body is considered as a mathematical model of the device. The boundary problem is solved through the finite-element package ANSYS. Under the numerical solution, PKR-7M piezoceramic is taken as a piezoelectric material, whereas fiberglass, duralumin, steel are considered as a plate material. Aluminum is used as a material of the inertial mass. Two cases are studied computationally. In the first case, the fixed side executes vertical harmonic vibrations at a given frequency and with a preset amplitude, in the second case, the force varying in a harmonic fashion is applied to this side. The device resonance frequency dependence upon the plate thickness for various materials and upon the value of the inertial element mass is studied. The results are presented graphically that allows finding the resonant frequency for certain sizes. The output potential dependences at the free electrodes of the piezoelectric elements on the resonant frequencies and in the low-frequency region on the same parameters are investigated. These results are also presented graphically that allows a designer to select reasonable feature sizes and the mix of materials to optimize the device.