Auxetic clamped-clamped resonators for high-efficiency vibration energy harvesting at low-frequency excitation

Here, we utilize the auxetic concept to improve output electrical power and reduce resonance frequency for the piezoelectric vibration energy harvesting. An energy harvester consists of a proof mass and two supporter beams with piezoelectric patches, is proposed. Presented energy harvester prototype is appropriate for applications with limited allowable displacement. Three different auxetic structures are proposed and their performances are compared to the conventional plain system. Finite element (FE) modelling is provided to evaluate these structures and optimize their geometrical parameters and electrical resistance to achieve the best energy harvesting performance. The FE model is validated through experimental tests in which the energy harvesters with optimized parameters are excited by an electrodynamic shaker in different frequencies. It is shown that the proposed designs are able to remarkably enhance the harvested electrical power with respect to the plain structure. The experimental tests show that the Auxetic-I, II and III could enhance the output electrical power with a magnification factor of 10, 6.7 and 6.1 respectively, compared to the conventional structure. The resonant working frequency reduced up to 30.45%, 19.55% and 27.53% for different designs.

Automated summary

The utilization of auxetic concept enhances output electrical power and reduces resonance frequency for piezoelectric vibration energy harvesting. Finite element modeling is used to evaluate and optimize structures for optimal energy harvesting performance. Experimental tests demonstrate the significant increase in harvested electrical power with the new designs.