提出一种新型的磁耦合变势能阱双稳态压电颤振能量收集器，设计了外部磁场作用下颤振能量收集系统的双稳态构型，并利用弹性支撑的外部磁铁的运动实现了变势能阱技术，解释了变势能阱双稳态对颤振能量收集系统的性能增强机理。建立了磁力-压电-气动弹性耦合的颤振能量收集系统的动力学分析模型，根据非线性磁偶极模型以及平衡点稳定性理论，讨论了系统出现双稳态构型的参数条件。对磁耦合双稳态颤振能量收集系统的动态特性进行了数值仿真研究，结果显示，双稳态构型能够使无磁力颤振能量收集系统的超临界颤振行为转变为亚临界颤振，发生极限环振动的风速能够降低50%以上，拓宽了能量收集器的有效工作风速范围，并分析了磁铁间距、磁偶极矩对能量收集性能的影响规律。采用弹性支撑的外部磁铁的运动来自适应调节内外部磁铁之间的距离，达到变势能阱的目的，有效地降低了双稳态的势能阱深度，使系统更容易发生双稳态势能阱间的跃迁运动，从而在双稳态的设计基础上，实现了能量收集工作风速范围和输出电功率的同步提升，为低风速下的能量收集提供了一种有效的设计途径。
This paper proposes a novel magnet-coupled variable-potential-well bi-stable flutter energy harvester to enhance energy harvesting performance in low air speed regions. The bi-stable configuration under the action of the external magnetic field is designed and the variable-potential-well technique realized using the nonlinear magnetic force and the motion of external magnet with elastic support. The energy harvesting performance is enhanced and its mechanism revealed. The governing equation of the magnet-coupled flutter energy harvester is established. The bi-stable configuration is theoretically analyzed according to the nonlinear magnetic dipole model and the stability theory. The dynamic responses of the energy harvester are numerically simulated. The results show that the bi-stable configuration transforms the supercritical flutter behavior of the non-magnet-coupled system into subcritical flutter one. Therefore, the cut-in air speed of the limit cycle oscillation can be reduced by more than 50%, significantly broadening the effective air speed range for energy harvesting. The influence of the magnet separation distance and magnetic dipole moment on the flutter energy harvesting performance is investigated. Based on the variable-potential-well technique, the separation distance and the corresponding potential well are adaptively adjusted, enabling easier undertaking of the inter-well vibration by the system. Therefore, the beneficial enhancements of the air speed range and output power are simultaneously realized, providing a new design approach for energy harvesting application in low speed air flow.
[1] ERTURK A, RENNO J M, INMAN D J. Modeling of piezoelectric energy harvesting from an L-shaped beam-mass structure with an application to UAVs[J]. Journal of Intelligent Material Systems and Structures, 2009, 20(5):529-544.
[2] 刘莉, 杜孟尧, 张晓辉, 等. 太阳能/氢能无人机总体设计与能源管理策略研究[J]. 航空学报, 2016, 37(1):144-162. LIU L, DU M Y, ZHANG X H, et al. Conceptual design and energy management strategy for UAV with hybrid solar and hydrogen energy[J]. Acta Aeronautica et Astronautica Sinica, 2016, 37(1):144-162(in Chinese).
[3] WANG Y, INMAN D J. Simultaneous energy harvesting and gust alleviation for a multifunctional composite wing spar using reduced energy control via piezoceramics[J]. Journal of Composite Materials, 2013, 47(1):125-146.
[4] JUNG H J, KIM I H, JANG S J. An energy harvesting system using the wind-induced vibration of a stay cable for powering a wireless sensor node[J]. Smart Materials and Structures, 2011, 20(7):075001.
[5] ZHAO D, EGA E. Energy harvesting from self-sustained aeroelastic limit cycle oscillations of rectangular wings[J]. Applied Physics Letters, 2014, 105(10):103903.
[6] De MARQUI Jr C, ERTURK A, INMAN D J. Piezoaeroelastic modeling and analysis of a generator wing with continuous and segmented electrodes[J]. Journal of Intelligent Material Systems and Structures, 2010, 21(10):983-993.
[7] ERTURK A, VIEIRA W G R, De MARQUI Jr C, et al. On the energy harvesting potential of piezoaeroelastic systems[J]. Applied Physics Letters, 2010, 96(18):184103.
[8] ABDELKEFI A, GHOMMEM M. Piezoelectric energy harvesting from morphing wing motions for micro air vehicles[J]. Theoretical and Applied Mechanics Letters, 2013, 3(5):052004.
[9] BRYANT M, GARCIA E. Modeling and testing of a novel aeroelastic flutter energy harvester[J]. Journal of Vibration and Acoustics, 2011, 133(1):011010.
[10] XIANG J, WU Y, LI D. Energy harvesting from the discrete gust response of a piezoaeroelastic wing:Modeling and performance evaluation[J]. Journal of Sound and Vibration, 2015, 343:176-193.
[11] STANTON S C, MCGEHEE C C, MANN B P. Nonlinear dynamics for broadband energy harvesting:Investigation of a bistable piezoelectric inertial generator[J]. Physica D:Nonlinear Phenomena, 2010, 239(10):640-653.
[12] ZHOU S, CAO J, WANG W, et al. Modeling and experimental verification of doubly nonlinear magnet-coupled piezoelectric energy harvesting from ambient vibration[J]. Smart Materials and Structures, 2015, 24(5):055008.
[13] TANG L, YANG Y, SOH C K. Improving functionality of vibration energy harvesters using magnets[J]. Journal of Intelligent Material Systems & Structures, 2012, 23(13):1433-1449.
[14] LI K, YANG Z, GU Y, et al. Nonlinear magnetic-coupled flutter-based aeroelastic energy harvester:modeling, simulation and experimental verification[J]. Smart Materials and Structures, 2018, 28(1):015020.
[15] ALHADIDI A H, ABDERRAHMANE H A, DAQAQ M F, et al. Exploiting stiffness nonlinearities to improve flow energy capture from the wake of a bluff body[J]. Physica D:Nonlinear Phenomena, 2016:30-42.
[16] ZHANG L B, ABDELKEFI A, DAI H, et al. Design and experimental analysis of broadband energy harvesting from vortex-induced vibrations[J]. Journal of Sound and Vibration, 2017, 408:210-219.
[17] ZHOU Z, QIN W, ZHU P, et al. Scavenging wind energy by a Y-shaped bi-stable energy harvester with curved wings[J]. Energy, 2018, 153:400-412.
[18] COTTONE F, VOCCA H, GAMMAITONI L. Nonlinear energy harvesting[J]. Physical Review Letters, 2009, 102(8):080601.
[19] LAN C, QIN W. Enhancing ability of harvesting energy from random vibration by decreasing the potential barrier of bistable harvester[J]. Mechanical Systems and Signal Processing, 2017:71-81.
[20] 刘祥建, 陈仁文. Rainbow型压电单膜片换能结构负载电压和输出功率分析[J]. 航空学报, 2011, 32(3):561-570. LIU X J, CHEN R W. Analysis of load voltage and output power for rainbow shape piezoelectric monomorph energy transferring elements[J]. Acta Aeronautica et Astronautica Sinica, 2011, 32(3):561-570(in Chinese).
[21] WANG H, TANG L. Modeling and experiment of bistable two-degree-of-freedom energy harvester with magnetic coupling[J]. Mechanical Systems and Signal Processing, 2017, 86:29-39.
[22] ABDELKEFI A, NAYFEH A H, HAJJ M R. Design of piezoaeroelastic energy harvesters[J]. Nonlinear Dynamics, 2012, 68(4):519-530.
[23] LI K, YANG Z, ZHOU S. Performance enhancement for a magnetic-coupled bi-stable flutter-based energy harvester[J]. Smart Materials and Structures, 2020,29(8):085045.
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