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Exploiting Non-linearity to Improve the Performance of Point Wave Energy Absorbers.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Exploiting Non-linearity to Improve the Performance of Point Wave Energy Absorbers./
Author:	Khasawneh, Mohammad Ahmad.
Description:	1 online resource (205 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 85-05, Section: B.
Contained By:	Dissertations Abstracts International85-05B.
Subject:	Mechanical engineering. -
Online resource:	click for full text (PQDT)
ISBN:	9798380855846

Exploiting Non-linearity to Improve the Performance of Point Wave Energy Absorbers.
Khasawneh, Mohammad Ahmad.

Exploiting Non-linearity to Improve the Performance of Point Wave Energy Absorbers. - 1 online resource (205 pages)

Source: Dissertations Abstracts International, Volume: 85-05, Section: B.

Thesis (Ph.D.)--New York University Tandon School of Engineering, 2023.

Includes bibliographical references

The heaving point wave energy absorber (PWA) has emerged as the most popular and promising solution for harnessing wave energy. This technology currently occupies 40\\% of the market share and is favored over other types of wave energy absorbers due to its simplicity, efficiency, and scalability. In its most basic form, a PWA consists of a partially submerged buoy connected to a linear electromagnetic generator by a rigid cable that is fixed to the seabed. When sea waves set the buoy into motion, the cable is pulled and relative motion is created between a magnet and a coil, generating a current in the coil as per Faraday's law of induction.Despite their success, PWAs still face two major challenges that, when resolved, can make them the ideal choice for wave energy generation. First, current PWAs are resonance-based and, therefore, operate efficiently only within the resonance bandwidth of the absorber. This happens when the natural frequency of the absorber is close to one of the dominant frequencies in the wave energy spectrum. However, because of the high stiffness of the hydrostatic restoring force resulting from buoyancy, the natural frequency of the absorber is typically higher than that of the dominant frequencies in the wave energy spectrum. As a result, to reduce its natural frequency, the absorber must be augmented with a heavy submerged body or other complex mechanical and control solutions. Second, even when incorporating the proper design means to reduce the frequency of the PWA, much of the available wave energy is still lost. This is because the resonant bandwidth of the PWA is much narrower than the spectrum of the incident waves whose energy is distributed over a wide range of frequencies.To address these issues, this dissertation aims to intentionally introduce nonlinearities into the design of PWAs and exploit their influence to develop broadband PWAs whose response is less sensitive to variations in the wave frequency. The proposed research is twofold. The first is concerned with the development, analysis, and testing of a novel PWA concept that utilizes nonlinear modal interactions, specifically a two-to-one internal resonance energy pump to achieve a broadband frequency response. The second builds upon the current literature, which deals with utilizing a bi-stable restoring force to improve the transduction of PWAs. While a few papers have discussed this concept through numerical simulations, none addressed it using analytical and experimental tools. Analytical tools will pave the way towards optimizing the design parameters for enhanced performance, while experiments will serve to validate the notion that bi-stability can indeed be used to improve the performance of PWAs. This work serves to fill these two gaps by analyzing the response of bi-stable PWAs using analytical tools and building a proper experimental testbed to assess their performance under real harmonic wave conditions.By addressing these issues, this research is expected to lead to a step-change in the performance limits of current PWAs, making the technology more viable. It will also contribute significantly to delineating the influence of nonlinearities on the performance of PWAs, leading to more efficious wave energy harvesting systems.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9798380855846Subjects--Topical Terms:

557493
Mechanical engineering.
Subjects--Index Terms:

Bi-stabilityIndex Terms--Genre/Form:

554714
Electronic books.

Exploiting Non-linearity to Improve the Performance of Point Wave Energy Absorbers.
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504 $a Includes bibliographical references
520 $a The heaving point wave energy absorber (PWA) has emerged as the most popular and promising solution for harnessing wave energy. This technology currently occupies 40\\% of the market share and is favored over other types of wave energy absorbers due to its simplicity, efficiency, and scalability. In its most basic form, a PWA consists of a partially submerged buoy connected to a linear electromagnetic generator by a rigid cable that is fixed to the seabed. When sea waves set the buoy into motion, the cable is pulled and relative motion is created between a magnet and a coil, generating a current in the coil as per Faraday's law of induction.Despite their success, PWAs still face two major challenges that, when resolved, can make them the ideal choice for wave energy generation. First, current PWAs are resonance-based and, therefore, operate efficiently only within the resonance bandwidth of the absorber. This happens when the natural frequency of the absorber is close to one of the dominant frequencies in the wave energy spectrum. However, because of the high stiffness of the hydrostatic restoring force resulting from buoyancy, the natural frequency of the absorber is typically higher than that of the dominant frequencies in the wave energy spectrum. As a result, to reduce its natural frequency, the absorber must be augmented with a heavy submerged body or other complex mechanical and control solutions. Second, even when incorporating the proper design means to reduce the frequency of the PWA, much of the available wave energy is still lost. This is because the resonant bandwidth of the PWA is much narrower than the spectrum of the incident waves whose energy is distributed over a wide range of frequencies.To address these issues, this dissertation aims to intentionally introduce nonlinearities into the design of PWAs and exploit their influence to develop broadband PWAs whose response is less sensitive to variations in the wave frequency. The proposed research is twofold. The first is concerned with the development, analysis, and testing of a novel PWA concept that utilizes nonlinear modal interactions, specifically a two-to-one internal resonance energy pump to achieve a broadband frequency response. The second builds upon the current literature, which deals with utilizing a bi-stable restoring force to improve the transduction of PWAs. While a few papers have discussed this concept through numerical simulations, none addressed it using analytical and experimental tools. Analytical tools will pave the way towards optimizing the design parameters for enhanced performance, while experiments will serve to validate the notion that bi-stability can indeed be used to improve the performance of PWAs. This work serves to fill these two gaps by analyzing the response of bi-stable PWAs using analytical tools and building a proper experimental testbed to assess their performance under real harmonic wave conditions.By addressing these issues, this research is expected to lead to a step-change in the performance limits of current PWAs, making the technology more viable. It will also contribute significantly to delineating the influence of nonlinearities on the performance of PWAs, leading to more efficious wave energy harvesting systems.
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