Dynamic model of an electromagnetic actuator for vibration control of a cantilever beam with a tip mass

Cantilever beams have found intensive and extensive uses as underlying mechanisms for energy transduction in sensors as well as in energy harvesters. In magnetoelectric (ME) transduction, the underlying cantilever beam usually will undergo magnetic coupling effect. As the beam itself is either banded with magnetic transducer or magnets, the dynamic motion of the cantilever can be modified due to the magnetic force between the magnets and ME sensors. In this study, the dynamic response of a typical spiral cantilever beam with magnetic coupling is investigated. The spiral cantilever acts as the resonator of an energy harvester with a tip mass in the form of magnets, and a ME transducer is positioned in the air gap and interacts with the magnets. It is expected that this spiral configuration is capable of performing multiple vibration modes over a small frequency range and the response frequencies can be magnetically tunable. The experimental results show that the magnetic coupling between the magnets and the transducer plays a favorable role in achieving tunable resonant frequencies and reducing the frequency spacings. This will benefits the expansion of the response band of a device and is especially useful in energy harvesting.

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Nonlinear vibration control of a cantilever beam by a nonlinear energy sink

Mechanism and Machine Theory ◽

10.1016/j.mechmachtheory.2011.11.007 ◽

2012 ◽

Vol 50 ◽

pp. 134-149 ◽

Cited By ~ 48

Author(s):

Z. Nili Ahmadabadi ◽

S.E. Khadem

Keyword(s):

Vibration Control ◽

Nonlinear Vibration ◽

Cantilever Beam ◽

Nonlinear Energy Sink ◽

Nonlinear Vibration Control ◽

Energy Sink ◽

Nonlinear Energy

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Multimodal Energy Harvesting System: Piezoelectric and Electromagnetic

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x08099965 ◽

2008 ◽

Vol 20 (5) ◽

pp. 625-632 ◽

Cited By ~ 153

Author(s):

Yonas Tadesse ◽

Shujun Zhang ◽

Shashank Priya

Keyword(s):

Energy Harvesting ◽

Resonance Frequency ◽

Permanent Magnet ◽

Cantilever Beam ◽

Piezoelectric Energy Harvesting ◽

Prototype System ◽

Finite Element Software ◽

Piezoelectric Energy ◽

Energy Harvesting System ◽

Tip Mass

In this study, we report a multimodal energy harvesting device that combines electromagnetic and piezoelectric energy harvesting mechanism. The device consists of piezoelectric crystals bonded to a cantilever beam. The tip of the cantilever beam has an attached permanent magnet which, oscillates within a stationary coil fixed to the top of the package. The permanent magnet serves two purpose (i) acts as a tip mass for the cantilever beam and lowers the resonance frequency, and (ii) acts as a core which oscillates between the inductive coils resulting in electric current generation through Faraday's effect. Thus, this design combines the energy harvesting from two different mechanisms, piezoelectric and electromagnetic, on the same platform. The prototype system was optimized using the finite element software, ANSYS, to find the resonance frequency and stress distribution. The power generated from the fabricated prototype was found to be 0.25 W using the electromagnetic mechanism and 0.25 mW using the piezoelectric mechanism at 35 g acceleration and 20 Hz frequency.

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