Electromechanical analysis of a bending-torsion coupling piezoelectric energy harvester

Piezoelectric energy harvester devices have been widely used for collection of the vibration energy. Especially, the cantilever structure has been extensively studied to optimizing its energy harvesting performance. In this paper, a new type of bending torsion coupled piezoelectric energy harvester is proposed with the combination of the elastic connection and the optimized design of the eccentric mass. The energy harvesting performance under indirect impact load is analyzed by the theory of mechanical vibration and Hamiltonian principle. The geometry effect of the tip mass is investigated. The theoretical calculation method is verified by comparison with the finite element method. The results show that reasonable resistance selection and the frequency matching of the main structure and the energy capture structure will significantly change the energy harvesting effect. The frequency matching of the structures can be optimized by improving the eccentric arrangement. It is demonstrated that the proposed structure of the piezoelectric energy harvester has better energy harvesting efficiency as compared with the traditional structures.