ORCID Profile
0000-0002-6229-4871
Current Organisation
University of New South Wales
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Solid Mechanics | Mechanical Engineering | Numerical Modelling and Mechanical Characterisation
Emerging Defence Technologies | Expanding Knowledge in Engineering | Energy not elsewhere classified |
Publisher: IOP Publishing
Date: 12-05-2014
Publisher: SPIE
Date: 09-03-2014
DOI: 10.1117/12.2044993
Publisher: AIP Publishing
Date: 06-09-2021
DOI: 10.1063/5.0063488
Publisher: Springer Science and Business Media LLC
Date: 28-04-2020
Publisher: Elsevier BV
Date: 04-2019
Publisher: AIP Publishing
Date: 11-02-2013
DOI: 10.1063/1.4792737
Abstract: This letter presents a comparative study of different tip cross-sections for small scale wind energy harvesting based on galloping phenomenon. A prototype device is fabricated with a piezoelectric cantilever and a tip body with various cross-section profiles (square, rectangle, triangle, and D-shape) and tested in a wind tunnel. Experimental results demonstrate the superiority of the square-sectioned tip for the low cut-in wind speed of 2.5 m/s and the high peak power of 8.4 mW. An analytical model is established and verified by the experimental results. It is recommended that the square section should be used for small wind galloping energy harvesters.
Publisher: IOP Publishing
Date: 12-06-2015
Publisher: ACM
Date: 11-11-2013
Publisher: Elsevier BV
Date: 07-2017
Publisher: AIP Publishing
Date: 03-02-2020
DOI: 10.1063/1.5134948
Abstract: This Letter proposes a compact bistable galloping oscillator for achieving enhanced power generation from concurrent wind and base vibration. The harvester consists of a D-shaped bluff body attached to a piezoelectric cantilever, with magnetic interaction introduced between the bluff body and a fixed windward prism. Both theoretical analysis and experiment demonstrate the remarkably broadened synchronization bandwidth for concurrent energy harvesting. In the experiment, the voltage steadily increases from 26.6 V at 8.5 Hz to 40.7 V at 12 Hz, achieving a 10 times wider bandwidth than the linear galloping harvester.
Publisher: IOP Publishing
Date: 15-11-2019
Publisher: Elsevier BV
Date: 02-2018
Publisher: IEEE
Date: 07-2018
Publisher: Hindawi Limited
Date: 09-07-2021
DOI: 10.1155/2021/5511817
Abstract: In this study, based on the lumped-parameter theory and the Lagrange approach, a novel and generalized bending-torsional-axial coupled dynamic model for analyzing the load sharing behavior in the herringbone planetary gear train (HPGT) is presented by taking into account the actual structure of herringbone gears, manufacturing errors, time-dependent meshing stiffness, bearing deflections, and gyroscopic effects. The model can be applied to the analysis of the vibration of the HPGT with any number of planets and different types of manufacturing errors in different floating forms. The HPGT equivalent meshing error is analyzed and derived for the tooth profile errors and manufacturing eccentric errors of all components in the HPGT system. By employing the variable-step Runge–Kutta approach to calculate the system dynamic response, in conjunction with the presented calculation approach of the HPGT load sharing coefficient, the relationships among manufacturing errors, component floating, and load sharing are numerically obtained. The effects of the combined errors and single error on the load sharing are, respectively, discussed. Meanwhile, the effects of the support stiffness of the main components in the HPGT system on load sharing behavior are analyzed. The results indicate that manufacturing errors, floating components, and system support stiffness largely influence the load sharing behavior of the HPGT system. The research has a vital guiding significance for the design of the HPGT system.
Publisher: AIP Publishing
Date: 10-04-0001
DOI: 10.1063/5.0136134
Abstract: This Letter reports an litude-robust nonlinear dual-functional metastructure that combines bistable and monostable-hardening mechanisms in the local resonators for simultaneous energy harvesting and vibration suppression. The concept is verified by experiments using a primary beam with six pairs of piezoelectric cantilevered oscillators and numerical analyses using a fully coupled electromechanical model for varying base vibration acceleration and load resistance. The results show that the design offers a wide bandgap at high accelerations, attenuation of transmission peaks, and generation of power over a broad bandwidth, outperforming its linear, pure bistable, and pure monostable counterparts. The dual-functional capabilities are further quantitatively assessed by using a weighted index that reflects both the vibration and power generation behaviors. This study demonstrates opportunities in development of the smart nonlinear metastructures for simultaneous vibration suppression and energy harvesting.
Publisher: SAGE Publications
Date: 19-02-2015
Abstract: Energy harvesting from aeroelastic instabilities has attracted numerous interests with the purpose of implementing self-powered wireless sensing networks. Meanwhile, considerable efforts have been devoted to optimizing the interface circuit to boost the power output from vibration-based piezoelectric energy harvester, such as impedance matching, synchronized charge extraction, and synchronized switching harvesting on inductor. However, application of these circuits in aeroelastic energy harvesting has received far less attentions. With an experimentally validated equivalent circuit model, this article investigates the feasibility of employing the synchronized charge extraction interface for a galloping-based piezoelectric energy harvester. The performance of synchronized charge extraction circuit is compared with a standard circuit, revealing three main advantages of synchronized charge extraction in galloping-based piezoelectric energy harvester system: first, the output power from synchronized charge extraction is independent of electrical load, eliminating the requirement of impedance matching and thus ensuring the flexibility of adjusting the galloping-based piezoelectric energy harvester system for practical applications second, the synchronized charge extraction circuit helps to save piezoelectric materials by 75% compared to the standard circuit and third, the displacement litude of galloping-based piezoelectric energy harvesters with synchronized charge extraction is much smaller, alleviating the fatigue problem and enhancing the durability of the harvesting system. Finally, a theoretical criterion is proposed to determine the applicable region of synchronized charge extraction in galloping-based piezoelectric energy harvester.
Publisher: Elsevier BV
Date: 08-2020
Publisher: SPIE
Date: 21-03-2019
DOI: 10.1117/12.2522088
Publisher: Elsevier BV
Date: 02-2023
Publisher: Elsevier BV
Date: 2021
Publisher: ACM
Date: 11-11-2013
Publisher: SPIE
Date: 02-04-2015
DOI: 10.1117/12.2084000
Publisher: Hindawi Limited
Date: 05-2020
DOI: 10.1002/ER.5228
Publisher: American Society of Mechanical Engineers
Date: 19-09-2012
Abstract: A conventional vibration energy harvester is usually designed as a linear single-degree-of-freedom (1DOF) resonator. The efforts to improve its efficiency involve two aspects, i.e., enlarging the magnitude of output and widening the operating bandwidth. In this paper, we propose a magnetic coupled cantilever piezoelectric energy harvester (PEH) to achieve the above two goals. Different from other reported magnetic coupled PEHs, the magnetic interaction in the proposed design is introduced by a magnetic oscillator. Firstly, the lumped parameter models are established for the conventional linear PEH, the nonlinear PEH with a fixed magnet and the proposed PEH with a magnetic oscillator. The governing equations of the three systems are then provided in the state space form and their dynamics can be simulated by numerical integration. Subsequently, experimental tests are performed to validate the models. Both experiment and simulation show that the dynamics of the magnetic oscillator is able to not only broaden the operating bandwidth but also enhance the maximum power output of the PEH. Based on the validated model, parametric study is conducted to optimize the system performance.
Publisher: SPIE
Date: 24-04-2020
DOI: 10.1117/12.2558465
Publisher: AIP Publishing
Date: 06-02-2023
DOI: 10.1063/5.0128616
Abstract: Vortex-induced vibration (VIV) and wake galloping are two aeroelastic instability phenomena with similar underlying mechanisms related to vortex shedding. Inspired by this common feature, a two-degree-of-freedom (2DOF) piezoelectric aeroelastic energy harvester (PAEH) is proposed, which employs VIV and wake galloping mechanisms with their respective benefits to improve the wind energy harvesting performance in a wide wind speed range. The proposed 2DOF PAEH overcomes the limitations of conventional one-degree-of-freedom VIV and wake galloping energy harvesters, with the former being only effective in a single and narrow lock-in wind speed range and the latter failing to work at low wind speeds. The modal frequencies of the 2DOF PAEHs are easily manipulated, and the twin mechanisms improve power generation over two lock-in regions at low wind speeds by the VIV mechanism and a third power generation region at relatively higher wind speeds due to wake galloping. A coupled aero-electro-mechanical model is developed and verified by wind tunnel experiments on a prototype. The results show that the proposed harvester efficiently extracts wind energy in a wide wind speed range from 1.1 to 6 m/s. The influence of the distance between the two parallel bluff bodies, in which distance is a critical parameter, on the voltage output is experimentally investigated, revealing three distinct aerodynamic behaviors at different distances.
Publisher: IOP Publishing
Date: 19-02-2015
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 10-2022
Publisher: SAGE Publications
Date: 25-06-2022
DOI: 10.1177/1045389X211026381
Abstract: This paper proposes a softening nonlinear aeroelastic galloping energy harvester for enhanced energy harvesting from concurrent wind flow and base vibration. Traditional linear aeroelastic energy harvesters have poor performance with quasi-periodic oscillations when the base vibration frequency deviates from the aeroelastic frequency. The softening nonlinearity in the proposed harvester alters the self-excited galloping frequency and simultaneously extends the large- litude base-excited oscillation to a wider frequency range, achieving frequency synchronization over a remarkably broadened bandwidth with periodic oscillations for efficient energy conversion from dual sources. A fully coupled aero-electro-mechanical model is built and validated with measurements on a devised prototype. At a wind speed of 5.5 m/s and base acceleration of 0.1 g, the proposed harvester improves the performance by widening the effective bandwidth by 300% compared to the linear counterpart without sacrificing the voltage level. The influences of nonlinearity configuration, excitation magnitude, and electromechanical coupling strength on the mechanical and electrical behavior are examined. The results of this paper form a baseline for future efficiency enhancement of energy harvesting from concurrent wind and base vibration utilizing monostable stiffness nonlinearities.
Publisher: Hindawi Limited
Date: 2017
DOI: 10.1155/2017/3585972
Abstract: The concept of harvesting ambient energy as an alternative power supply for electronic systems like remote sensors to avoid replacement of depleted batteries has been enthusiastically investigated over the past few years. Wind energy is a potential power source which is ubiquitous in both indoor and outdoor environments. The increasing research interests have resulted in numerous techniques on small-scale wind energy harvesting, and a rigorous and quantitative comparison is necessary to provide the academic community a guideline. This paper reviews the recent advances on various wind power harvesting techniques ranging between cm-scaled wind turbines and windmills, harvesters based on aeroelasticities, and those based on turbulence and other types of working principles, mainly from a quantitative perspective. The merits, weaknesses, and applicability of different prototypes are discussed in detail. Also, efficiency enhancing methods are summarized from two aspects, that is, structural modification aspect and interface circuit improvement aspect. Studies on integrating wind energy harvesters with wireless sensors for potential practical uses are also reviewed. The purpose of this paper is to provide useful guidance to researchers from various disciplines interested in small-scale wind energy harvesting and help them build a quantitative understanding of this technique.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2015
Publisher: IOP Publishing
Date: 11-2013
Publisher: SPIE
Date: 20-04-2022
DOI: 10.1117/12.2613326
Publisher: Elsevier BV
Date: 04-2023
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2017
Publisher: Association for Computing Machinery (ACM)
Date: 13-02-2018
DOI: 10.1145/3173039
Abstract: Whereas a lot of efforts have been put on energy conservation in wireless sensor networks (WSNs), the limited lifetime of these systems still h ers their practical deployments. This situation is further exacerbated indoors, as conventional energy harvesting (e.g., solar) may not always work. To enable long-lived indoor sensing, we report in this article a self-sustaining sensing system that draws energy from indoor environments, adapts its duty-cycle to the harvested energy, and pays back the environment by enhancing the awareness of the indoor microclimate through an “energy-free” sensing. First of all, given the pervasive operation of heating, ventilation, and air conditioning (HVAC) systems indoors, our system harvests energy from airflow introduced by the HVAC systems to power each sensor node. Secondly, as the harvested power is tiny, an extremely low but synchronous duty-cycle has to be applied whereas the system gets no energy surplus to support existing synchronization schemes. So, we design two complementary synchronization schemes that cost virtually no energy. Finally, we exploit the feature of our harvester to sense the airflow speed in an energy-free manner. To our knowledge, this is the first indoor wireless sensing system that encapsulates energy harvesting, network operating, and sensing all together.
Publisher: SPIE
Date: 20-04-2022
DOI: 10.1117/12.2611733
Publisher: SAGE Publications
Date: 12-01-2022
DOI: 10.1177/1045389X211072520
Abstract: This paper presents a study of a two-degree-of-freedom (2DOF) piezoelectric energy harvester (PEH) under concurrent aeroelastic and base excitation. The governing equations of the theoretical model under the combined excitation are developed and solved analytically using the harmonic balance method. Based on the electro-mechanical analogies, an equivalent circuit model is established. The energy harvesting performance of the 2DOF PEH under different wind speeds but the same base excitation is investigated. Voltage litudes of various response components with different frequencies are predicted by the analytical method and verified by the circuit simulation. The root-mean-square (RMS) voltage is used to measure the actual performance of the 2DOF PEH. Around the resonance state, the 2DOF PEH has been found to produce a larger voltage output than the conventional SDOF PEH. Moreover, several interesting phenomena, such as the quasi-periodic oscillation and the peak-to-valley transition, have been observed in the circuit simulation and explained by the analytical solution. The developed methodology in this paper can be easily adapted to analyze other similar types of multiple-degree-of-freedom (MDOF) PEHs under concurrent aeroelastic and base excitation.
Publisher: IOP Publishing
Date: 09-2019
DOI: 10.1088/1757-899X/531/1/012081
Abstract: This paper presents a novel energy harvesting device driven by concurrent aeroelastic vibration and base vibratory excitation. The harvester undergoes flow-induced limit-cycle oscillation under galloping instability, and at the same time, inertia force induced vibration is present due to the base vibratory excitation. A limitation with a traditional linear aeroelastic energy harvester is that effective energy harvesting from combined sources is only achievable within a narrow frequency range. To overcome this issue, bistability is introduced by exploiting nonlinear restoring force. A lumped aero-electro-mechanical model is established to incorporate the mutual coupling between the wind flow, piezoelectric element, nonlinear structure and circuit. Dynamic responses are investigated for different bistable configurations. Results show that the proposed harvester achieves a significantly widened bandwidth over which the two excitation frequencies are forced to lock into each other, and both vibratory and aeroelastic energy are effectively harnessed.
Publisher: American Society of Mechanical Engineers
Date: 19-09-2012
Abstract: A galloping piezoelectric harvester for small wind energy harvesting usually consists of a cantilever beam cl ed at one end and a tip body attached to its free end. The tip body has significant influence on the aeroelastic characteristic of the harvester thus the efficiency of energy harvesting. However, no systematic study on the tip body is available in the literature. This article focuses on the effect of tip body on the performance of the harvester. A prototype device is fabricated with different tip bodies having various cross sections, lengths, and masses. Wind tunnel tests are conducted to determine the influence of these parameters on the power generated. A peak output power of 8.4 mW is achieved at a wind velocity of 8 m/s for the harvester with a tip of square section. An analytical model integrating electromechanical and aerodynamic formulations is established, and the results agree well with the experiments. It is recommended that the tip of square section should be used for galloping energy harvesters.
Publisher: SPIE
Date: 22-03-2021
DOI: 10.1117/12.2585151
Publisher: Elsevier BV
Date: 07-2022
Publisher: Elsevier BV
Date: 04-2020
Publisher: MDPI AG
Date: 20-06-2019
Abstract: This paper presents an analysis of galloping-based wind energy harvesters with piezoelectric and electromagnetic transductions. The lumped parameter models of the galloping-based piezoelectric energy harvester (GPEH) and galloping-based electromagnetic energy harvester (GEMEH) are developed and the approximate analytical solutions of the equations are derived using the harmonic balance method (HBM). The accuracy of the approximate analytical solutions is validated by the numerical solutions. A parametric study is then conducted based on the validated models and solutions to understand the effects of the dimensionless load resistance, r, and electromechanical coupling strength (EMCS) on various quantities indicating the performance of the harvesters, including the dimensionless oscillating frequency, cut-in wind speed, displacement, and average power output. The results show that both r and EMCS can affect the dimensionless oscillating frequencies of the GPEH and GEMEH in a narrow frequency range around the natural frequency. A significant decrease in the displacement around r = 1 for GEPH and at a low r for GEMEH indicates the d ing effect induced by the increase in EMCS. There are two optimal r to achieve the maximal power output for GPEH given strong EMCS while there is only one optimal r for GEMEH. Both GPEH and GEMEH show similar characteristics in that the optimal power outputs can reach saturation with an increase of the EMCS. The findings from the parametric study provide useful guidelines for the design of galloping-based energy harvesters with different energy conversion mechanisms.
Publisher: Hindawi Limited
Date: 09-2020
DOI: 10.1002/ER.5878
Start Date: 02-2021
End Date: 02-2025
Amount: $425,775.00
Funder: Australian Research Council
View Funded Activity