Design Considerations for Optimal Absorption of Energy from a Vibration Source by an Array of Harvesters

AbstractDynamic vibration absorption is a passive technique for suppressing unintended vibrations. Optimal absorption of energy from a vibration source entails the determination of absorber parameters such as resonant frequency and damping. In the present work, we propose a method to obtain these parameters for a generic case of large number of identical vibration absorbers placed on a vibration source. We discuss an iterative procedure to find the optimum absorber resonant frequency and damping by minimizing the total energy absorbed by the system. We also analyse the influence of damping of the entire set of absorbers on the total energy absorbed and the effect of the absorber mass on the bandwidth of absorption. The proposed method is verified by analysing the response of a set of cantilever absorber beams placed on a vibrating cantilever plate. The resonant frequencies of the system with different number of absorbers are verified experimentally. We identify, using our method, the absorber mass, resonant frequency and damping of the absorber at which significant amount of energy supplied to the system flows into absorbers. A potential application of this method in the context of energy harvesting is the design of harvesters for a given vibration source. We emphasize through our work that monitoring energies in the system and optimizing them is both rational and vital for designing multiple harvesters that absorb energy from a given vibration source optimally.

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01 / Determination of analytical precision in calculating total energy expenditure using the doubly labelled water method in humans

10.26226/morressier.5b1a467c3b823805c63bffb8 ◽

2018 ◽

Author(s):

Ruby Baker ◽

Michelle Venables

Keyword(s):

Energy Expenditure ◽

Total Energy ◽

Total Energy Expenditure ◽

Doubly Labelled Water ◽

Analytical Precision

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Enhancement of a New Methodology Based on the Impulse Excitation Technique for the Nondestructive Determination of Local Material Properties in Composite Laminates

Applied Sciences ◽

10.3390/app11010101 ◽

2020 ◽

Vol 11 (1) ◽

pp. 101

Author(s):

Carlo Boursier Niutta

Keyword(s):

Resonant Frequency ◽

Elastic Properties ◽

Composite Laminates ◽

Concentrated Mass ◽

Modal Shape ◽

Nondestructive Determination ◽

Material Orientation ◽

Impulse Excitation ◽

Clamping System

A new approach for the nondestructive determination of the elastic properties of composite laminates is presented. The approach represents an improvement of a recently published experimental methodology based on the Impulse Excitation Technique, which allows nondestructively assessing local elastic properties of composite laminates by isolating a region of interest through a proper clamping system. Different measures of the first resonant frequency are obtained by rotating the clamping system with respect to the material orientation. Here, in order to increase the robustness of the inverse problem, which determines the elastic properties from the measured resonant frequencies, information related to the modal shape is retained by considering the effect of an additional concentrated mass on the first resonant frequency. According to the modal shape and the position of the mass, different values of the first resonant frequency are obtained. Here, two positions of the additional mass, i.e., two values of the resonant frequency in addition to the unloaded frequency value, are considered for each material orientation. A Rayleigh–Ritz formulation based on higher order theory is adopted to compute the first resonant frequency of the clamped plate with concentrated mass. The elastic properties are finally determined through an optimization problem that minimizes the discrepancy on the frequency reference values. The proposed approach is validated on several materials taken from the literature. Finally, advantages and possible limitations are discussed.

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Determination of total energy expenditure, resting metabolic rate and physical activity in lean and overweight people

Zeitschrift für Ernährungswissenschaft ◽

10.1007/bf01617805 ◽

1997 ◽

Vol 36 (4) ◽

pp. 310-312 ◽

Cited By ~ 4

Author(s):

F. Thielecke ◽

J. Möseneder ◽

A. Kroke ◽

K. Klipstein-Grobusch ◽

H. Boeing ◽

...

Keyword(s):

Physical Activity ◽

Energy Expenditure ◽

Metabolic Rate ◽

Total Energy ◽

Resting Metabolic Rate ◽

Total Energy Expenditure ◽

Overweight People

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The determination of resonant frequencies and decay factors

Journal of the Institution of Electrical Engineers ◽

10.1049/jiee-1.1924.0078 ◽

1924 ◽

Vol 62 (330) ◽

pp. 517-525

Author(s):

E. Mallett

Keyword(s):

Resonant Frequencies

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The Determination of Total Energy and Nutrient Intake in Older Adults in Turkey

Studies on Ethno-Medicine ◽

10.1080/09735070.2015.11905449 ◽

2015 ◽

Vol 9 (3) ◽

pp. 319-326

Author(s):

Nurcan Yabanci Ayhan ◽

Pelin Bilgic ◽

Isil Simsek ◽

Muhittin Tayfur ◽

Nobuko Hongu

Keyword(s):

Older Adults ◽

Total Energy ◽

Nutrient Intake ◽

Energy And Nutrient Intake

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Piezoelectric MEMS Acoustic Transducer with Electrically-Tunable Resonant Frequency

Micromachines ◽

10.3390/mi13010096 ◽

2022 ◽

Vol 13 (1) ◽

pp. 96

Author(s):

Alessandro Nastro ◽

Marco Ferrari ◽

Libor Rufer ◽

Skandar Basrour ◽

Vittorio Ferrari

Keyword(s):

Acoustic Emission ◽

Resonant Frequency ◽

Piezoelectric Layer ◽

Flexural Mode ◽

Resonant Frequencies ◽

Voltage Mode ◽

Acoustic Transducer ◽

Aln Film ◽

Doped Silicon ◽

Piezoelectric Mems

The paper presents a technique to obtain an electrically-tunable matching between the series and parallel resonant frequencies of a piezoelectric MEMS acoustic transducer to increase the effectiveness of acoustic emission/detection in voltage-mode driving and sensing. The piezoelectric MEMS transducer has been fabricated using the PiezoMUMPs technology, and it operates in a plate flexural mode exploiting a 6 × 6 mm doped silicon diaphragm with an aluminum nitride (AlN) piezoelectric layer deposited on top. The piezoelectric layer can be actuated by means of electrodes placed at the edges of the diaphragm above the AlN film. By applying an adjustable bias voltage Vb between two properly-connected electrodes and the doped silicon, the d31 mode in the AlN film has been exploited to electrically induce a planar static compressive or tensile stress in the diaphragm, depending on the sign of Vb, thus shifting its resonant frequency. The working principle has been first validated through an eigenfrequency analysis with an electrically induced prestress by means of 3D finite element modelling in COMSOL Multiphysics®. The first flexural mode of the unstressed diaphragm results at around 5.1 kHz. Then, the piezoelectric MEMS transducer has been experimentally tested in both receiver and transmitter modes. Experimental results have shown that the resonance can be electrically tuned in the range Vb = ±8 V with estimated tuning sensitivities of 8.7 ± 0.5 Hz/V and 7.8 ± 0.9 Hz/V in transmitter and receiver modes, respectively. A matching of the series and parallel resonant frequencies has been experimentally demonstrated in voltage-mode driving and sensing by applying Vb = 0 in transmission and Vb = −1.9 V in receiving, respectively, thereby obtaining the optimal acoustic emission and detection effectiveness at the same operating frequency.

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Investigation On The Optimal Tunable Bi-Stable Clustered Energy Conversion Inspired Dynamic Vibration Absorbers: A Theoretical Study

10.21203/rs.3.rs-796801/v1 ◽

2021 ◽

Author(s):

Xingbao Huang ◽

Xiao Zhang ◽

Bintang Yang

Keyword(s):

Energy Conversion ◽

Vibration Control ◽

Conversion Efficiency ◽

Energy Conversion Efficiency ◽

Vibration Absorbers ◽

Input Energy ◽

Mass Ratio ◽

Vibration Absorption ◽

Dynamic Vibration Absorbers ◽

Conversion Performance

Abstract This paper introduces an energy conversion inspired vibration control methodology and presents a representative prototype of tunable bi-stable energy converters. This work is concerned on improving the vibration absorption and energy conversion performance of tunable bi-stable clustered energy conversion inspired dynamic vibration absorbers (EC-DVAs). The deterministic parametric analysis of the energy transfer performance of clustered EC-DVAs is conducted. Firstly, nonlinear vibration behaviors including transient energy transfer and snap-through motions are studied, and then effects of EC-DVA number on vibration control is investigated. Furthermore, the optimal computation based on adjusting the length ratio (namely bi-stable potential barrier height) is developed to obtain the maximum energy conversion efficiency of clustered EC-DVAs and the minimum residual kinetic energy of the primary system considering different number of clustered EC-DVAs. Moreover, the optimal calculation based on optimal EC-DVA number is also developed to achieve the most excellent vibration absorption and energy conversion performance. Finally, the optimal calculation based on optimal mass ratio is conducted. Numerical simulations show that when the total mass ratio is constant the snap-through motions of each EC-DVA depend remarkably on EC-DVA number; the energy conversion efficiency and residual kinetic energy after dynamic length ratio optimization is independent on ambient input energy and EC-DVA number; The energy conversion efficiency and vibration absorption performance based on optimal EC-DVA number maintain high efficiency and stable when the ambient input energy or the potential energy of clustered EC-DVAs varies. The optimal mass ratio is large when the system’s potential barrier is too large and the ambient input energy is small. Therefore, the presented tunable bi-stable system of clustered EC-DVAs with appropriate bi-stable potential function and proposed optimization strategies is a potential alternative for vibration control of mechanical components exposed to varying impulses.

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THE STUDY OF ACOUSTIC CHARACTERISTICS OF THE PERFORATED AND HOMOGENOUS PLATES WITH SIMILAR GEOMETRICAL DIMENSIONS

Akustika ◽

10.36336/akustika20193279 ◽

2019 ◽

Vol 32 ◽

pp. 79-82

Author(s):

Valery Kirpichnikov ◽

Lyudmila Drozdova ◽

Alexei Koscheev ◽

Ernst Myshinsky

Keyword(s):

Resonant Frequency ◽

Acoustic Radiation ◽

Perforated Plate ◽

Acoustic Characteristics ◽

Resonant Frequencies ◽

Perforated Plates ◽

Resonance Frequencies ◽

Flexural Vibrations ◽

Geometrical Dimensions

The resonance frequencies of the flexural vibrations, input vibration excitability and acoustic radiation of the homogeneous and perforated plates were investigated. It is established that the average reduction range of the lower resonant frequency of flexural vibrations of the tested plates with the holes virtually coincides with the predictive estimate. The levels of the input vibration excitability of the perforated plate at the lower resonant frequencies exceeded the levels at the corresponding frequencies of the homogeneous plates greater than the calculated value. The levels of resonance acoustic radiation of the perforated plate were significantly less than of the homogeneous one.

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