Now showing 1 - 10 of 11
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    Dynamics of symmetric and asymmetric potential well-based piezoelectric harvesters: A comprehensive review
    (01-10-2021)
    Giri, Abhijeet Madhukar
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    Arockiarajan, Arunachalakasi
    Small and micro-scale energy harvesting is an essential and viable option for the powering of portable and maintenance free electronic devices, wireless sensor nodes, and similar applications. In this regard, piezoelectric harvesters have presented promising outcomes. This article provides a sequential, comprehensive, and informative survey of potential well based models and studies related to piezoelectric harvesters (PEH). Piezoelectric materials used for energy harvesting are discussed briefly, following which a non-dimensional generalized model is derived to set the discussion on a common platform. Dynamics of various potential well configurations are presented using the generalized model before discussing specific models and related studies. The survey is classified into symmetric and asymmetric potential well categories. Under the symmetric head, lumped and distributed parameter linear models and tuning methods for improving the broadband response are discussed. Subsequently, studies related to nonlinear mono-stable, bi-stable, and tri-stable potentials showing interwell, multi-periodic and chaotic oscillations with improved broadband response are discussed. The asymmetric section studies the influence of asymmetries on the performance of the mono-stable, bi-stable, and tri-stable configurations. Few other configurations outside the cantilever type PEH were mentioned, realizing the widespread research in this field. Important observations and future challenges for performance improvement are also discussed.
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    The effect of noise on the response of a vertical cantilever beam energy harvester
    (01-05-2015)
    Friswell, M. I.
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    Bilgen, O.
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    Litak, G.
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    Adhikari, S.
    An energy harvesting concept has been proposed comprising a piezoelectric patch on a vertical cantilever beam with a tip mass. The cantilever beam is excited in the transverse direction at its base. This device is highly nonlinear with two potential wells for large tip masses, when the beam is buckled. For the pre-buckled case considered here, the stiffness is low and hence the displacement response is large, leading to multiple solutions to harmonic excitation that are exploited in the harvesting device. To maximise the energy harvested in systems with multiple solutions the higher amplitude response should be preferred. This paper investigates the amplitude of random noise excitation where the harvester is unable to sustain the high amplitude solution, and at some point will jump to the low amplitude solution. The investigation is performed on a validated model of the harvester and the effect is demonstrated experimentally.
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    Energy generation in a hybrid harvester under harmonic excitation
    (01-01-2018)
    Rajarathinam, M.
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    A hybrid energy harvester combining piezoelectric and electromagnetic transduction mechanisms is designed to harvest vibration energy. The system comprises of a cantilever beam PZT harvester and a magnetic mass hung through a spring at the free end. The beam with PZT harvests energy using piezoelectric effect while the hanging mass oscillates through a copper coil to harvest electromagnetic energy. This paper studies power harvested from the hybrid harvester under harmonic excitation using experimental and analytical evaluations. Comparisons are made with the standalone piezoelectric and electromagnetic harvesters under similar excitation environment. The study shows that the present hybrid harvester can harvest energy at a broad range of frequencies. Furthermore, a few parametric studies are carried out to understand the device output performance. The bandwidth of the harvester and the power harvested within the bandwidth can be designed based on the stiffness of the system and also by changing the electromechanical coupling coefficient. Studies reported also show that bandwidth of harvester can also be increased by increasing the magnetic mass.
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    Array enhanced stochastic resonance for augmented energy harvesting
    (01-08-2022)
    Aravindan, M.
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    Research studies on vibration energy harvesting have shown from time to time that bistable harvesters offer a lucrative solution for harnessing substantial magnitude of power across a broad range of frequencies. This exciting potential of bistable harvesters has bred interest towards investigating the possibility of enhancement in power by coupling multiple of them. In this regard, the present work analyzes the behavior of a 1-D array of bistable piezoelectric harvesters mechanically coupled in the nearest-neighbor configuration under a noise perturbed periodic base excitation. The numerical study reports a resonant-like behavior of the total power with system size for certain noise levels of excitation. The parametric regimes to which the system size resonance effect is confined have been identified. The present work attempts to provide an intuitive understanding into the role of system size on the total harvested power under a noisy environment. Inferences drawn from the results of this work shall help in designing a harvesting system to realize broadband power generation.
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    Energy harvesting from near periodic structures
    (01-01-2015)
    Malaji, P. V.
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    In this research energy harvesting from near periodic structure is discussed. The near periodic system consists of two pendulums connected using a common linear spring. Mistuning in the simple coupled pendulum system is achieved by varying the length of one of the pendulums. Effect of this mistuning on amount of energy harvested is developed analytically and numerically. This will be discussed in this paper and at the same time effect of harvesting on mistuning will be presented. It is shown that with a proper electrical damping, optimal power can be obtained and effect of mistuning can be minimized. Same analysis is carried out with energy harvesting from both the pendulums. In case of harvesting from both the pendulums the harvesting bandwidth is increased and electrical damping required to minimize mistuning is more than that in case of harvesting with mistuned pendulum alone.
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    Exploring 1:3 internal resonance for broadband piezoelectric energy harvesting
    (15-05-2021)
    Aravindan, M.
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    Recent literature has shown that the spectral characteristics of a harvester can be significantly improved by invoking internal resonance between the modes. Taking motivation from this premise, the present work analyzes the nonlinear dynamics and harvesting performance of a 1:3 internally resonant piezoelectric cantilever beam with a lumped mass under harmonic excitation. The governing modal equations are derived using Galerkin's approach and Hamilton's principle of least action. The method of multiple scales has been used to study the dynamics of the harvester in the proximity of primary resonances. The steady state periodic responses of the harvester are obtained using a pseudo-arc continuation technique and subsequently, their implications on the harvested power are discussed. The frequency responses of the harvested power are shown to boast significantly high magnitudes across a wide frequency band due to the energy transfer between the modes near the primary resonances. Results presented in the study show that the higher mode invoked through internal resonance plays a significant role in broadband power generation. The transfer of energy between the modes is found to occur only within a certain threshold of excitation level which in turn affects the magnitude of harvested power. Numerical simulations have also been carried out the results of which are compared against the analytical results. The outcomes of this first-hand analysis shall aid in the proposition of an efficient design for a broadband energy harvester.
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    Broadband energy harvesting with mechanically coupled harvesters
    (01-03-2017)
    Malaji, P. V.
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    This article investigates an array of pendulums as a potential broadband energy harvester. Closed form expression of the total power is analytically obtained. Effect of parameters on the total power harvested and on frequency band of the harvested power is accessed numerically. Finally experiments are carried out for arrays with two to five pendulums, which strongly supports the numerical observations. Different configurations are studied; (a) pendulums in the array are independent of each other, (b) pendulums are coupled using springs in between. The effect of mechanical grounding, where in the extreme pendulums are connected to the support through a spring, is also investigated. Observations show that array of coupled pendulums with mechanical grounding increased the bandwidth of harvesting frequency. The bandwidth and the total power harvested saturates with the number of pendulums.
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    Analysis of Harvesting Energy from Mistuned Multiple Harvesters with and without Coupling
    (01-01-2016)
    Malaji, P. V.
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    Adhikari, S.
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    Friswell, M. I.
    Energy harvesting has received a lot of attention in the recent past. At present a single device does not harvested energy enough to power up an electronic sensors. In order to increase the power output multiple identical harvesters are used. When multiple harvesters are used, they bring in non-uniformity in their physical parameters due to variability during manufacturing or even during deployment. Therefore, 'n' numbers of harvesters do not necessary produce 'n' times the harvested power of a single device. The variability in parameters is less enough to be coined as mistuning. In this paper, an analysis of multiple energy harvesters is studied. The harvesters are assumed to show mistuning. The study is further extended to understand the effect of mechanical coupling between the harvesters. For simplification, pendulums are considered as the harvesters, with magnetic tip masses for the electromagnetic energy harvesting. Mistuning is achieved by varying the length of the pendulums. A generalized mathematical model for n coupled harvesters with mistuning is developed. Simulations are performed with the number of harvesters varying from 2 to 6 with ±1% non-repetitive mistuning in the lengths of the harvesters, and a comparison of the power harvested between mechanically coupled and uncoupled harvesters is presented.
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    Energy harvesting from dynamic vibration pendulum absorber
    (01-01-2019)
    Malaji, P. V.
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    Rajarathinam, M.
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    Jaiswal, V.
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    Howard, I. M.
    Dynamic vibration absorbers (DVAs) have proven to be an effective passive technique to suppress device vibration, with many realistic implementations in structures, buildings, and machines. Vibration energy harvesting is a process used to convert unwanted vibrations of a host structure into electrical energy. In this paper, a harmonic single degree-of-freedom system is considered consisting of a pendulum absorber and electromagnetic energy harvesting transduction mechanism. These types of DVAs are suitable for control of multi-story buildings, where for the simplicity of analysis a two degree-of-freedom system which models the building with the absorber is considered. Controlling the vibrations of buildings is the primary objective, and harvesting the energy from the dynamic vibration pendulum absorber at the same time is the secondary objective. Parametric analyses are performed. It is observed that proper system parameter selection is key for reducing the vibration amplitude of the primary system and for enhancing the energy harvested from the secondary system. Optimization analysis based on the genetic algorithm approach is used to optimize the system parameters. It is observed that with a proper selection of parameters, wideband energy can be harvested along with reduction in vibration of the building.
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    Coupled piezo-multiple electromagnetic energy harvesting
    (01-01-2023)
    Rajarathinam, M.
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    Aravindan, M.
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    Vinothkrishnan, V.
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    This work studies the performance of a hybrid energy harvester with multiple electromagnetic generators under harmonic and random motions. A reduced order model is derived for numerical analysis. Experiments are conducted to validate the numerical results. Results show that the hybrid harvester with two electromagnetic subsystems can generate sufficient magnitude of power sustained over a large frequency region. Parametric studies are carried out and reported. The proposed harvester is capable of producing high voltage and high current simultaneously. Finally, a finite element model is developed for further analysis to find the optimal position and number of electromagnetic subsystems for enhanced power.