Nonlinear modeling and efficacy of VIV-based energy harvesters: Monostable and bistable designs

• Published in: Mechanical systems and signal processing 2022-04, Vol.169, p.108775, Article 108775
• Main Authors: Naseer, R., Abdelkefi, A.
• Format: Article
• Language: English
• Subjects: Broadband synchronization region; Buckling; Electrical loads; Electrical resistance; Energy harvesting; Excitation; Frequency analysis; Linear analysis; Load resistance; Magnetic fields; Magnets; Mathematical models; Multi-stability; Nonlinearity; Reduced order models; Resonant frequencies; Synchronism; Vortex-induced vibration; Vortex-induced vibrations; Wind resistance; Wind speed
• ISSN: 0888-3270; 1096-1216
• DOI: 10.1016/j.ymssp.2021.108775

•Performance of a magnetoelastic multi-stability energy harvester is investigated.•Combination of vortex-induced vibration (VIV) and base excitation is studied and explained.•A nonlinear reduced-order model based on the Galerkin discretization is derived.•Comparative studies between monostable and bistable configurations are performed.•Quenching phenomenon is observed and affected the harvester’s response depending on various factors. In this effort, performance of a magnetoelastic multi-stability energy harvester is investigated in monostable and bistable configurations while working under combination of vortex-induced vibration (VIV) and base excitation. For this purpose, a mathematical model is developed that accounts for coupled lift force, magnetic force, cylinder’s motion, and generated voltage. First, a linear analysis is carried out to investigate the effects of electrical load resistance on the coupled natural frequency of the system and its impact on the synchronization region. Static and frequency analyses are performed to identify the point of buckling based on the distance between the magnets. Then, a reduced-order model based on the Galerkin discretization is derived to investigate the effects of various nonlinearities on the harvester’s response. A convergence analysis is examined up till seven modes and it is found that three modes are sufficient. To compare the efficacy of the energy harvester at same coupled frequency in monostable and bistable regimes, three pairs of datasets are selected. Various parametric studies are presented to investigate the impacts of distance between the magnets, electrical load resistance, frequency, and wind speed. This study not only presents one of its kind quantitative comparisons of performance of the energy harvester working in monostable and bistable regimes at same coupled frequency but also provides an insight to performance of the harvester under combined effect of VIV and base excitation. In this regard, quenching phenomenon is visible. In addition, performance trends in pre-synchronization region, synchronization region, hysteresis region, and post synchronization regions are explained by presenting four wind speed graphs together. Some phase portraits and time histories are included for further exploration. In nutshell, the study is very useful for understanding of monostable and bistable designs and their working under VIV as well as hybrid excitations.