Development of Low-Frequency Broadband Vibration Energy Harvester based on Soft Magneto-Sensitive Elastomer

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dc.contributor.advisor Aw, KC en
dc.contributor.advisor Tang, L en Yang, Zhaoshu en 2020-03-26T19:12:20Z en 2019 en
dc.identifier.uri en
dc.description.abstract Vibration energy harvester (VEH) is an electromechanical device that can convert the ambient vibrational energy into useful electricity. This technology is believed to be a promising alternative to conventional batteries as energy source for small electronics. However, the traditional VEHs are usually designed as a linear oscillator with narrow frequency bandwidth and constructed by inflexible structure. These properties may significantly limit their applications in many scenarios, where the ambient vibrations are confined in low frequency domain and contain multiple frequency components. In this thesis, we endeavour to develop a light-weight broadband VEH operating in low frequency domain (< 10 Hz) and small acceleration (<0.2 g) conditions. This VEH is constructed by a cantilever based on soft magneto-sensitive elastomer (SMSE) material. This material is fabricated by mixing some iron particles in a soft polymer base before crosslinking. The SMSE is quite flexible, so that a low resonance frequency could be easily achieved without largely increasing the mass. Moreover, the SMSE cantilever exhibit a unique softening nonlinearity, which could be applied to broaden the frequency bandwidth of the VEH. Experimental and theoretical studies are conducted for fabrication, charactering the SMSE material and analysing its unique nonlinearity. A piezoelectric VEH is developed with the SMSE cantilever and a polyvinylidene fluoride (PVDF) layer. This harvester can achieve a broad frequency bandwidth in low frequency domain and low acceleration levels, but its energy harvesting efficiency is extremely low due to the fact that the soft substrate of SMSE is difficult to deform the PVDF layer with relatively high stiffness, apart from the low coupling coefficient of PVDF itself. An electet-based VEH (eVEH) is then developed using the SMSE cantilever. The voltage generation mechanism of the eVEH is studied in view of its charge migration process. The impact-based frequency up-conversion technology is utilized in the eVEH and an asymmetrical frequency response profile of the SMSE cantilever is proposed to mitigate the side effect of the impacts and preserve the broadband behaviour of the eVEH. Efficient broadband energy harvesting is achieved with such an SMSE eVEH device. According to the experimental results, the proposed broadband eVEH based on SMSE cantilever can deliver an average power output of 40.32 μW at its optimal load resistance and the effective working frequency bandwidth is 4.0 Hz to 8.2 Hz. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof PhD Thesis - University of Auckland en
dc.relation.isreferencedby UoA99265292514002091 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights.uri en
dc.rights.uri en
dc.title Development of Low-Frequency Broadband Vibration Energy Harvester based on Soft Magneto-Sensitive Elastomer en
dc.type Thesis en Mechatronics Engineering en The University of Auckland en Doctoral en PhD en
dc.rights.holder Copyright: The author en
dc.rights.accessrights en
pubs.elements-id 797020 en
pubs.record-created-at-source-date 2020-03-27 en

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