Broadband vibration energy harvester utilizing three out-of-plane modes of one vibrating body

Park, Shi Baek; Jang, Seong-Cheol; Kim, In Ho; Choi, Yong Je

doi:10.1088/1361-665x/aa891e

Cited by 6 publications

(5 citation statements)

References 21 publications

(26 reference statements)

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“…The stiffness matrix ( ) and modal matrix ( ) in (47) must satisfy the following five constraints for the realization of stiffness: 1) The first constraint is such that the orthogonality of the vibration modes (or, vibration centers) with respect to the inertia matrix has to be satisfied. We obtained (20) from this constraint and the coordinates of vibration centers given by (20) are rewritten in terms of , , and ( Fig. 10):…”

Section: Design Methodsmentioning

confidence: 99%

“…To satisfy (20), the remaining coordinates of vibration centers can be written as 2) Under the assumption of low damping with the identical modal damping ratio, i.e., ( = 1 , ⋯ , 6) = , another constraint was given by (42-1) and (42-2). If we substitute the coordinates obtained from the first constraint of (48) and (49) into (42-1) and (42-2), we obtain the expressions for the distances of 1 , 3 , 1 and 3 ( Fig.…”

Section: Design Methodsmentioning

confidence: 99%

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Design for Prespecified Ratios Between Six Energy Peaks Using a Planar Symmetric Dual-Body Vibration System

et al. 2020

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When the design of a vibration system requires a broad bandwidth, the numbers and the ratios of energy peaks become major design factors. In particular, within a specific range of frequency, an increase in the number of peaks can widen the valid working bandwidth by decreasing the distances between peaks. In this paper, a planar symmetric dual-body vibration system is used to implement desired work ratios at six target frequencies. The geometrical relation between vibration modes and energy peaks is investigated to develop the design method and introduces geometrical representation of vibration modes of a symmetric dualbody system together. Six vibration modes of a symmetric dual-body system are divided into two groups with three vibration modes that represent the centers of vibration. It is shown that the orthocenters of two modal triangles of each of two rigid bodies coincide with its center of mass. The frequency responses to both direct and base excitations are derived in terms of vibration centers and target frequencies, and thus work ratios are obtained. Finally, the derived equation of work ratios is used to determine the modal matrix composed of the vibration modes when the desired mass, specific work ratios, and target resonant frequencies are given. Consequently, the corresponding stiffness matrix is found and realized. Numerical examples of four cases with different work ratios are presented to illustrate the proposed design method.

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Section: Design Methodsmentioning

confidence: 99%

Section: Design Methodsmentioning

confidence: 99%

Design for Prespecified Ratios Between Six Energy Peaks Using a Planar Symmetric Dual-Body Vibration System

et al. 2020

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“…Recently, some researchers [5]- [7] presented design methods of planar vibration system by use of geometric properties of in-plane modes. Park and Choi [8] utilized geometric properties of out-of-plane modes to design energy harvester with desired resonant frequencies. The transparent geometrical nature of vibrating systems may provide useful tools for design of a vibration system.…”

Section: Aaamentioning

confidence: 99%

The Conditions for a Linear Vibration System to Have Only Pure Rotation Modes

Lee

Ryu

Choi³

et al. 2020

IEEE Access

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This paper proposes a geometric approach to the conditions for mode decoupling of a vibration system of an elastically supported single rigid body and presents the conditions that the system has only pure rotation modes of vibration. A small oscillation of a rigid body is indeed a repetitive screw motion and thus vibration modes are expressed by screws in general, which results in the difficulty involved in solving a vibration problem. The complexity of a vibration system can be alleviated for both analysis and synthesis if the system has only rotation modes. In order to acquire the decoupling techniques, this paper begins by investigating a stiffness matrix which can be separated into the sum of two rank 3 stiffness matrices, which are realizable by using co-reciprocal line vectors. From the co-reciprocity, the separable stiffness matrix can be regarded as a linear transformation between two 3-systems of screws containing only line vectors. Using the properties of the linear transformation and the screw systems, the conditions for mode decoupling, or the conditions for only pure rotation modes are derived and described by geometric relations between inertia and stiffness, and three cases of vibration systems with simple geometric nature are identified. INDEX TERMS Screw theory, linear vibration, mode decoupling, planes of symmetry, pure rotation mode.

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“…This approach has been implemented using a serial or parallel array of structures with different resonant frequencies, 4–10 nonlinear springs or structures, 11–15 or multi-mode vibrating bodies. 16–19 These structures do not require any control power, but have disadvantages associated with their design complexity. The second approach is to continuously or intermittently tune the device.…”

Section: Introductionmentioning

confidence: 99%

Tunable yo-yo energy harvester with oblique springs

Kim

Jang

Park

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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In this study, a yo-yo vibrational energy harvesting device that can adjust its resonant frequency to the desired excitation frequency using geometrical control is proposed and investigated. The device employs a spring system, suspended proof mass, and set of reels and gears to convert translational input into rotational motion to power its generator. The spring system is composed of two symmetrical oblique springs, and its stiffness and the resonant frequency of the proposed harvester varies with the oblique angle between these springs. The characteristics of the oblique spring system are investigated accordingly, and it is shown that there exists a lower limit of stiffness; therefore, the achievable frequency bandwidth of the harvester can be determined. The method used to design the proposed tunable energy harvester so that it satisfies the desired frequency bandwidth is then provided. A prototype of the device was built and tested on a vibration table, and its performance is illustrated via a comparison with the results of numerical calculations. The results indicate that the proposed device is capable of harnessing the kinetic energy of the ocean waves.

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Broadband vibration energy harvester utilizing three out-of-plane modes of one vibrating body

Cited by 6 publications

References 21 publications

Design for Prespecified Ratios Between Six Energy Peaks Using a Planar Symmetric Dual-Body Vibration System

Design for Prespecified Ratios Between Six Energy Peaks Using a Planar Symmetric Dual-Body Vibration System

The Conditions for a Linear Vibration System to Have Only Pure Rotation Modes

Tunable yo-yo energy harvester with oblique springs

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