Optimization of the electro-mechanical response of the multilayer piezoelectric energy harvester

In this contribution, a design of novel cantilever beam energy harvester, composed of several ceramic layers with introduced high residual stresses, is proposed. The main aim of residual stresses is to protect the piezoelectric layer from cracking during the service of the harvester. A way to optimize composition of the multilayer energy harvester to receive both high apparent fracture toughness of the structure and simultaneously high electrical power of the harvester during its operation is presented. Both an analytical and a numerical model of the vibrational energy harvester are developed for this purpose. The increased resistance to fracture is achieved by means of high compressive stresses in the external ceramic layers. The electrical power output of the harvester is further optimized with respect to connected resistive load and excitation acceleration of vibrations. It was found that the optimal resistive load also leads to lowest mechanical stresses in particular laminate layers.