title: Peculiarities of the third natural frequency vibrations of a cantilever for the improvement of energy harvesting.
abstract: This paper focuses on several aspects extending the dynamical efficiency of a cantilever beam vibrating in the third mode. A few ways of producing this mode stimulation, namely vibro-impact or forced excitation, as well as its application for energy harvesting devices are proposed. The paper presents numerical and experimental analyses of novel structural dynamics effects along with an optimal configuration of the cantilever beam. The peculiarities of a cantilever beam vibrating in the third mode are related to the significant increase of the level of deformations capable of extracting significant additional amounts of energy compared to the conventional harvester vibrating in the first mode. Two types of a piezoelectric vibrating energy harvester (PVEH) prototype are analysed in this paper: the first one without electrode segmentation, while the second is segmented using electrode segmentation at the strain nodes of the third vibration mode to achieve effective operation at the third resonant frequency. The results of this research revealed that the voltage generated by any segment of the segmented PVEH prototype excited at the third resonant frequency demonstrated a 3.4-4.8-fold increase in comparison with the non-segmented prototype. Simultaneously, the efficiency of the energy harvester prototype also increased at lower resonant frequencies from 16% to 90%. The insights presented in the paper may serve for the development and fabrication of advanced piezoelectric energy harvesters which would be able to generate a considerably increased amount of electrical energy independently of the frequency of kinematical excitation.
authors.affiliation: Institute of Mechatronics, Kaunas University of Technology, Studentu 56-123, Kaunas LT-51368, Lithuania. vytautas.ostasevicius@ktu.lt.
authors.forename: Vytautas
authors.initials: V
authors.lastname: Ostasevicius
authors.affiliation: Faculty of Mechanical Engineering and Design, Kaunas University of Technology, Studentu 56-338, Kaunas LT-51368, Lithuania. giedrius.janusas@ktu.lt.
authors.forename: Giedrius
authors.initials: G
authors.lastname: Janusas
authors.affiliation: Institute of Mechatronics, Kaunas University of Technology, Studentu 56-123, Kaunas LT-51368, Lithuania. ieva.milasauskaite@gmail.com.
authors.forename: Ieva
authors.initials: I
authors.lastname: Milasauskaite
authors.affiliation: Faculty of Electrical and Electronics Engineering, Kaunas University of Technology, Studentu 48-211, Kaunas LT-51368, Lithuania. mindaugas.zilys@ktu.lt.
authors.forename: Mindaugas
authors.initials: M
authors.lastname: Zilys
authors.affiliation: Faculty of Informatics, Kaunas University of Technology, Studentu 48-213, Kaunas LT-51368, Lithuania. laura.kizauskiene@ktu.lt.
authors.forename: Laura
authors.initials: L
authors.lastname: Kizauskiene
keywords: holography system; laser vibrometry; optimal configuration; piezoelectric layer; resonant frequency; vibration energy harvesting; vibro-impact motion