Simulation and experimental demonstration of improved efficiency in coupled piezoelectric cantilevers by extended strain distribution

A piezoelectric energy harvester design is proposed, which will achieve a wider bandwidth without compromising energy conversion efficiency for future use in e g gas turbines. By coupling two cantilevers where the tip of the bottom one is attached to the base of the upper one, the harvester will have a wider bandwidth and a higher power output compared to two optimally tuned single cantilevers, which to a large part is the effect of an extended strain distribution in the bottom cantilever in the coupled configuration. The design is compact, using only half the area compared to two parallel single cantilevers at the price of only a small increase in height. The coupled harvester displays approximately five times higher power output than two tuned single cantilevers. (C) 2015 Elsevier B.V. All rights reserved.