Performance enhancement of piezoelectric energy harvesting system using a corrugated cantilever beam

Abstract

In this paper, a piezoelectric energy harvesting device consisting of a proof mass and a corrugated cantilever beam is proposed in order to enhance its performance (i.e., an increase in output voltage as well as a reduction in resonant frequency). The sinusoidal or trapezoidal shape of a cantilever beam is able to make the bonding area of piezoelectric materials (e.g., polyvinylidene fluoride (PVDF) film) much larger, resulting in higher output voltages. Moreover, the natural frequency of the device can be significantly decreased due to low flexural rigidity of the beam member. This lownatural frequency device would fit well for civil engineering applications because most civil structures such as bridges and buildings have low natural frequencies. In order to examine the geometrical characteristics of the proposed device, an analytical development and a numerical simulation are carried out. Besides, shaking table tests are conducted with a prototype of energy harvesting device. It is demonstrated from numerical and experimental studies that the proposed energy harvester can shift down its resonant frequency considerably and generate much higher output power as compared with a conventional one having a flat (or straight) cantilever beam.