scholarly journals The fundamental frequencies of longitudinally vibrating rods carrying tip mass and transversally vibrating beams carrying tip mass by using several methods

2021 ◽  
Vol 42 (1) ◽  
pp. 209-217
Author(s):  
Aydın DEMİR
Keyword(s):  
Fundamental Frequencies ◽  
Vibrating Beams ◽  
Tip Mass

Analytical Modeling and Experimental Verification of the Vibrations of the Zigzag Microstructure for Energy Harvesting

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
M. Amin Karami ◽  
Daniel J. Inman
Keyword(s):  
Energy Harvesting ◽  
Resonance Condition ◽  
Low Frequency ◽  
Dominant Frequency ◽  
Design Guidelines ◽  
Ambient Vibration ◽  
Micro Electro Mechanical Systems ◽  
Fundamental Frequencies ◽  
Near Resonance ◽  
Tip Mass

This paper addresses an issue in energy harvesting that has plagued the potential use of harvesting through the piezoelectric effect at the micro-electro-mechanical systems (MEMS) scale. Effective energy harvesting devices typically consist of a cantilever beam substrate coated with a thin layer of piezoceramic material and fixed with a tip mass tuned to resonant at the dominant frequency of the ambient vibration. The fundamental natural frequency of a beam increases as its length decreases, so that at the MEMS scale the resonance condition occurs orders of magnitude higher than ambient vibration frequencies, rendering the harvester ineffective. Here, we propose a new geometry for MEMS scale cantilever harvesters with low fundamental frequencies. A “zigzag” geometry is proposed, modeled, and solved to show that such a structure would be able to vibrate near resonance at the MEMS scale. An analytical solution is presented and verified against Rayleigh’s method and is validated against a macroscale experiment. The analysis is used to provide design guidelines and parametric studies for constructing an effective MEMS scale energy harvesting device in the frequency range common to low frequency ambient vibrations, removing a current barrier.

scholarly journals Split Cantilever Multi-Resonant Piezoelectric Energy Harvester for Low-Frequency Application

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5077
Author(s):  
David Omooria Masara ◽  
Hassan El Gamal ◽  
Ossama Mokhiamar
Keyword(s):  
Energy Harvester ◽  
Low Frequency ◽  
Load Resistance ◽  
High Energy ◽  
The Finite Element Method ◽  
Fundamental Frequencies ◽  
Piezoelectric Energy ◽  
Wide Range ◽  
Bending Modes ◽  
Tip Mass

This paper presents a new way to design a broadband harvester for harvesting high energy over a low-frequency range of 10–15 Hz. The design comprises a cantilever beam with two parallel grooves to form three dissimilar length parallel branches, each with an unequal concentrated tip mass. The piezoelectric material covers the whole length on both sides of the beam to form a bimorph. Appropriate geometry and mass magnitudes are obtained by a parametric study using the Finite Element Method. The design was simulated in COMSOL Multiphysics to study its response. The first three bending modes were utilized in energy harvesting, resulting in three power peaks at their respective fundamental frequencies. The adequate load resistance determined was 5.62 kΩ, at which maximum power can be harvested. The proposed harvester was compared to two other harvesters presented in the literature for validation: First, an optimized conventional harvester while the proposed harvester is operating at adequate load resistance. Second, a multimodal harvester, while the proposed harvester is operating at a 10 kΩ load. The suggested harvester proved to be more efficient by harvesting sufficiently higher broadband energy and is applicable in a wide range of vibration environments because of its adaptability in design.

On the extremal fundamental frequencies of vibrating beams

1968 ◽  
Vol 4 (7) ◽  
pp. 667-674 ◽  
Author(s):  
R.M. Brach
Keyword(s):  
Fundamental Frequencies ◽  
Vibrating Beams

A Tape Striation Counting Method for Determining Fundamental Frequency

1979 ◽  
Vol 10 (4) ◽  
pp. 246-248 ◽  
Author(s):  
Peter B. Mueller ◽  
Marla Adams ◽  
Jean Baehr-Rouse ◽  
Debbie Boos
Keyword(s):  
Fundamental Frequency ◽  
Counting Method ◽  
Male And Female ◽  
Fundamental Frequencies ◽  
Counting Procedure ◽  
Female Subjects

Mean fundamental frequencies of male and female subjects obtained with FLORIDA I and a tape striation counting procedure were compared. The fundamental frequencies obtained with these two methods were similar and it appears that the tape striation counting procedure is a viable, simple, and inexpensive alternative to more costly and complicated procedures and instrumentation.

Complex formation and kinematic coupling: C2H4.PtCl3

1988 ◽  
Vol 53 (10) ◽  
pp. 2377-2384 ◽  
Author(s):  
Roman Řeřicha ◽  
Björg N. Cyvin ◽  
Jon Brunvoll ◽  
Sven J. Cyvin
Keyword(s):  
Complex Formation ◽  
Crystallographic Data ◽  
System Modelling ◽  
Vibrational Modes ◽  
Normal Coordinate ◽  
Kinematic Coupling ◽  
Fundamental Frequencies

Normal coordinate analyses including calculations of PED's were performed for C2H4.PtCl3 system modelling Zeise's anion, [(C2H4)PtCl3]-. The wedgewise distorsion of the C2H4 ligand known from the crystallographic data for Zeise's salt, was taken into account. Under these circumstances it was found that the kinematic couplings between the internal ligand and complex framework vibrational modes are rather small. The reliability of some existing assignments of the fundamental frequencies of Zeise's anion is discussed.

The impact of repetitive combined voltages with low and high fundamental frequencies on the ageing of cast resin

2005 ◽  
Author(s):  
T. Sels ◽  
J. Declercq ◽  
J. Lopez-Roldan ◽  
D. Van Dommelen ◽  
R. Belmans
Keyword(s):  
Fundamental Frequencies ◽  
The Impact

Centrifuge Modeling on Seismic Behavior of Pile in Liquefiable Soil Ground

2013 ◽  
Vol 479-480 ◽  
pp. 1139-1143
Author(s):  
Wen Yi Hung ◽  
Chung Jung Lee ◽  
Wen Ya Chung ◽  
Chen Hui Tsai ◽  
Ting Chen ◽  
...  
Keyword(s):  
Seismic Behavior ◽  
Soil Structure ◽  
Lateral Displacement ◽  
Bending Moment ◽  
Soil Liquefaction ◽  
Centrifuge Modeling ◽  
Shaking Table ◽  
Pile Head ◽  
Liquefiable Soil ◽  
Tip Mass

Dramatic failure of pile foundations caused by the soil liquefaction was founded leading to many studies for investigating the seismic behavior of pile. The failures were often accompanied with settlement, lateral displacement and tilting of superstructures. Therefore soil-structure interaction effects must be properly considered in the pile design. Two tests by using the centrifuge shaking table were conducted at an acceleration field of 80 g to investigate the seismic response of piles attached with different tip mass and embedded in liquefied or non-liquefied deposits during shaking. It was found that the maximum bending moment of pile occurs at the depth of 4 m and 5 m for dry sand and saturated sand models, respectively. The more tip mass leads to the more lateral displacement of pile head and the more residual bending moment.

scholarly journals Analysis of a Cantilevered Piezoelectric Energy Harvester in Different Orientations for Rotational Motion

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1206 ◽  
Author(s):  
Wei-Jiun Su ◽  
Jia-Han Lin ◽  
Wei-Chang Li
Keyword(s):  
Theoretical Model ◽  
Resonant Frequency ◽  
Rotational Motion ◽  
Axial Load ◽  
Energy Harvester ◽  
Excitation Frequency ◽  
Experimental Studies ◽  
Piezoelectric Energy ◽  
Piezoelectric Cantilever ◽  
Tip Mass

This paper investigates a piezoelectric energy harvester that consists of a piezoelectric cantilever and a tip mass for horizontal rotational motion. Rotational motion results in centrifugal force, which causes the axial load on the beam and alters the resonant frequency of the system. The piezoelectric energy harvester is installed on a rotational hub in three orientations—inward, outward, and tilted configurations—to examine their influence on the performance of the harvester. The theoretical model of the piezoelectric energy harvester is developed to explain the dynamics of the system and experiments are conducted to validate the model. Theoretical and experimental studies are presented with various tilt angles and distances between the harvester and the rotating center. The results show that the installation distance and the tilt angle can be used to adjust the resonant frequency of the system to match the excitation frequency.

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