Attractive forces of highly coercive permanent magnets in end magnetic clutches and plane magnetic systems

Krasilʼnikov, A. Ya.; Krasil’nikov, A. A.

doi:10.3103/s1068798x1006002x

Cited by 5 publications

(4 citation statements)

References 2 publications

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“…The former has the advantage of providing sufficiently accurate results without the need for meshing, applying periodicity conditions or imposing solution space limitations. Two types of analytical modeling approaches-surface charge (Coulombian/ Gilbert) [30][31][32][33][34][35] and current sheet (Amperian) [36][37][38]-are considered suitable for the estimation of 2D or 3D magnetic field components and the resulting forces acting between cuboidal, axisymmetric or arc-shaped permanent magnets in free space [29,39]. The underlying assumption of these models is that the total permeability is equal to that of vacuum (μ=μ 0 ) and superposition may be applied to calculate the force between magnets possessing any magnetic polarization direction.…”

Section: Modeling Of Magnetic Interactionmentioning

confidence: 99%

Analysis of magnetic plucking dynamics in a frequency up-converting piezoelectric energy harvester

Daukševičius

Kleiva

Grigaliūnas

2018

Smart Mater. Struct.

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The paper reports on numerical-experimental analysis of magnetic plucking, which is commonly applied for contactless mechanical frequency up-conversion in vibration energy harvesters with the aim of enhancing power output and efficiency under low-frequency (non)periodic excitations. In-plane magnetic plucking is examined thoroughly by treating it as a specific type of transient excitation that is governed by temporal characteristics of complex-shaped magnetic force impulses. The study focuses on systematic analysis of the measured dynamic and electric characteristics of a magnetically plucked cantilever-type piezoelectric energy harvester, which operates in quasi-static, transitory and dynamic modes. Experimental findings are supported by results of magnetostatic/dynamic finite element analysis, enabling to establish key criteria for attaining sharp impulsive excitation, which is a prerequisite for the highly effective frequency up-conversion. The criteria are defined in terms of dimensionless governing parameters that relate relevant temporal characteristics of magnetic force impulses (duration, ramping times) to the dynamic characteristics of the transducer (natural period, rise time). A phenomenon of transient resonance is demonstrated to deliver peak power and energy outputs. The reported findings are applicable to different magnetic plucking configurations and transducers of arbitrary natural frequency. The results serve as a guideline for the rational design of a wide variety of frequency up-converting devices by providing valuable insight into magnetic plucking dynamics, which is conducive to the development of high-performance biomechanical energy harvesters intended for self-powered wearable electronics.

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Section: Modeling Of Magnetic Interactionmentioning

confidence: 99%

Analysis of magnetic plucking dynamics in a frequency up-converting piezoelectric energy harvester

Daukševičius

Kleiva

Grigaliūnas

2018

Smart Mater. Struct.

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“…In normal operating conditions of sealed equip ment, attractive forces act between the half clutches of the frontal magnetic clutches (along the axis of rota tion) or the sections in the plane magnetic systems (perpendicular to their direction of motion) [2]. Those forces act on the roller or slip bearings of drive shafts and driven shafts in machines or sealed transporters.…”

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confidence: 99%

“…where F re is the repulsive force of the magnets in the plane magnetic system, N; S is the surface area (upper or lower) of the magnets, cm 2 …”

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confidence: 99%

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Repulsive forces of highly coercive permanent magnets in magnetic clutches and plane magnetic systems

Krasilʼnikov

Krasil’nikov

2013

Russ. Engin. Res.

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Use of a magnetic force exciter to vibrate a piezocomposite generating element in a small-scale windmill

Luong

Goo

2012

Smart Mater. Struct.

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A piezocomposite generating element (PCGE) can be used to convert ambient vibrations into electrical energy that can be stored and used to power other devices. This paper introduces a design of a magnetic force exciter for a small-scale windmill that vibrates a PCGE to convert wind energy into electrical energy. A small-scale windmill was designed to be sensitive to low-speed wind in urban regions for the purpose of collecting wind energy. The magnetic force exciter consists of exciting magnets attached to the device’s input rotor and a secondary magnet fixed at the tip of the PCGE. The PCGE is fixed to a clamp that can be adjusted to slide on the windmill’s frame in order to change the gap between exciting and secondary magnets. Under an applied wind force, the input rotor rotates to create a magnetic force interaction that excites the PCGE. The deformation of the PCGE enables it to generate electric power. Experiments were performed with different numbers of exciting magnets and different gaps between the exciting and secondary magnets to determine the optimal configuration for generating the peak voltage and harvesting the maximum wind energy for the same range of wind speeds. In a battery-charging test, the charging time for a 40 mA h battery was approximately 3 h for natural wind in an urban region. The experimental results show that the prototype can harvest energy in urban regions with low wind speeds and convert the wasted wind energy into electricity for city use.

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Attractive forces of highly coercive permanent magnets in end magnetic clutches and plane magnetic systems

Cited by 5 publications

References 2 publications

Analysis of magnetic plucking dynamics in a frequency up-converting piezoelectric energy harvester

Analysis of magnetic plucking dynamics in a frequency up-converting piezoelectric energy harvester

Repulsive forces of highly coercive permanent magnets in magnetic clutches and plane magnetic systems

Use of a magnetic force exciter to vibrate a piezocomposite generating element in a small-scale windmill

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