Multi Directional Piezoelectric Plate Energy Harvesters Designed By Topology Optimization Algorithm

In this letter, piezoelectric plate energy harvesters are designed by using topology optimization algorithm to harvest the excitation from different directions. The goal is to minimize the volume and weight of the whole structure so the harvesters can be used in small scale applications. To this aim, the profile of polarization is optimized by the topology optimization to overcome charge cancellation which is the main challenge in random direction excitation. Two optimized designs with uniform and nonuniform polarization profiles are obtained. Separated electrodes in the surfaces of the optimized design with non-uniform polarization are used to simulate the polarization profile. Numerical simulations by COMSOL multi-physics software show that the optimized design with separated electrodes can provide three times higher voltage and power than those obtained with non-optimized piezoelectric plate. Experimental investigation demonstrated that the same design with separated electrodes can have 2.17 and 1.93 times higher voltage than the full plate for out of plane and in-plane forces respectively.