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Energy-harvesting characteristics of damped piezoelectric phononic crystals and locally resonant and inertially amplified elastic metamaterials / IBRAHIM PATRICK
Swansea University Author: IBRAHIM PATRICK
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Copyright: The Author, Ibrahim Patrick, 2023. Distributed under the terms of a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0).
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DOI (Published version): 10.23889/SUthesis.63680
Abstract
Vibration energy harvesting is an emerging technology that enables electrical low-power generation using electromechanical structures or devices with piezoelectric elements. The prevailing approach for the characterization of the energy-harvesting performance in these devices is to consider a finite...
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Swansea, Wales, UK
2023
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| Institution: | Swansea University |
| Degree level: | Doctoral |
| Degree name: | Ph.D |
| Supervisor: | Adhikari, Sondipon. and Haddad Khodaparast, Hamed. |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa63680 |
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| Abstract: |
Vibration energy harvesting is an emerging technology that enables electrical low-power generation using electromechanical structures or devices with piezoelectric elements. The prevailing approach for the characterization of the energy-harvesting performance in these devices is to consider a finite structure operating under forced vibration conditions. This thesis introduces an alternative framework whereby the intrinsic energy-harvesting characteristics are rigorously quantified independent of the forcing and the structure size, and by doing so, the notion of a piezoelectric material is considered rather than a finite piezoelectric electromechanical structure. To illustrate the intrinsic quantification termed as “intrinsic energy-harvesting availability,” suspended monoatomic and diatomic piezoelectric phononic crystals (MPPnCs and DPPnCs) are considered and treated with Bloch’s theorem; consequently, the representative energy-harvesting characteristics within the span of the unit cell’s Brillouin zone (BZ) are formally quantified. In the absence of shunted piezoelectric elements, the wavenumber-dependent dissipation (damping-ratio) of the phononic crystal (PnC) is computed and shown to increase, as expected, with the level of prescribed (raw) damping. With the inclusion of the piezoelectric elements, the wavenumber-dependent dissipation rises by an amount proportional to the energy intrinsically available for harvesting; upon summation of this increased amount over all the damping-ratio branches (acoustic and optical modes) and subsequent complete integration over the BZ, a quantity representative of the net, i.e., useful, dissipative energy intrinsically available for harvesting is obtained. Piezoelectric elements comprising purely resistive and inductor-equipped shunt circuits are investigated. A parametric design study yielding optimal piezoelectric-element properties in terms of the proposed intrinsic energy-harvesting availability measure is also presented. Metadamping is the phenomenon of either enhanced or diminished intrinsic dissipation in a material emanating from the material’s internal structural dynamics. It has previously been demonstrated that an elastic locally resonant metamaterial (LRM) may be designed to exhibit higher or lower dissipation compared to a statically equivalent PnC with the same amount of prescribed damping. In this thesis, it is revealed that even further dissipation (positive metadamping) or, alternatively, further reduction of loss (negative metadamping) may be attained in an inertially amplified material (IAM) and an inertially amplified locally resonant metamaterial (IALRM) compared to a statically equivalent PnC and LRM with the same amount of prescribed damping. This is demonstrated by a passive configuration whereby an attenuation peak is generated by the motion of an auxiliary mass connected to the main/baseline mass by an inclined rigid link. It is further illustrated that by coupling the inertially amplified attenuation peak with that of a local-resonance attenuation peak, a trade-off between the temporal- and spatial-attenuation intensities associated with the material properties is observed for a given range of the inertial-amplifier angle, i.e., angle between the inclined rigid links and the central axis of the metamaterial. As a result, design for desired performance is possible along this trade-off regime by adjustment of the inertialamplifier angle, i.e., passive tuning. A region of monotonic increase in both attenuation types also exists for a different range of the inertial-amplifier angle. These results create a pathway for highly expanding the Ashby space for load-bearing and damping capacities orstiffness-damping capacities via design of a material’s internal structure. Building upon the work on characterizing the amount of useful dissipative energy intrinsically available for harvesting in a piezoelectric periodic media, the energy-harvesting availability is illustrated for a locally resonant piezoelectric metamaterial (LRPM) and an inertially amplified locally resonant piezoelectric metamaterial (IALRPM). It is also demonstrated that an LRPM with the same piezoelectric electrical parameters and the same amount of prescribed damping as for a statically equivalent reference piezoelectric phononic crystal (PPnC) exhibits an inherent emergence in the intrinsic energy-harvesting availability. This intrinsic phenomenon is termed as “metaharvesting.” Furthermore, it is shown that an IALRPM with the same piezoelectric electrical parameters and the same amount of prescribed damping as for a statically equivalent LRPM and a statically equivalent reference PPnCexhibits a further emergence in the intrinsic energy-harvesting availability, i.e., enhanced metaharvesting. |
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| Keywords: |
Phononic media, phononic crystal, local resonance, inertial amplification, piezoelectric, energy harvesting, periodic media, metaharvesting, metadamping, elastic metamaterial |
| College: |
Faculty of Science and Engineering |