Parametric Analysis and Voltage Generation Performance of a Multi-directional MDOF Piezoelastic Vibration Energy Harvester

Piezoelectric vibration energy harvesting has been extensively investigated in recent years and the majority of results focus on using the cantilever beam model under base driven motion. The main focus of this paper is to perform a parametric analysis of multi degrees of freedom piezo-elastic energy harvester to optimize the capability curve exploiting crossing/veering between modes. The structure under test consists of a combination of slender beams with one or more orthogonal beam segments placed on it. The resulting combined structure exhibits bending vibration modes in orthogonal planes. The cross and veering phenomena are studied in deep, attempting to improve the resulting mechanical-electrical energy conversion of the combined structure. A numerical model of the system under investigation is developed considering also non-classical damping. A parametric analysis of the system’ s performance due to geometrical and electrical properties variations are investigated to design a broadband harvester. An experimental analysis is performed on a test rig specially built to investigate the crossing and veering phenomena effects on the resulting output voltage from the energy harvester. Numerically simulated and experimental data are compared to provide information for updating the model as well as to address the efficiency of the harvester in terms of voltage generation.