Interaction Magnetic Force Calculation of Permanent Magnets Using Magnetization Charges and Discretization Technique

Vučković, Ana N.; Ilić, S; Aleksić, Slavoljub

doi:10.1080/02726343.2013.799950

Cited by 11 publications

(2 citation statements)

References 14 publications

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“…The magnetic force is derived based on fictitious magnetization charges [34]. In this section, the interactive magnetic force between two ring magnets is first derived.…”

Section: Magnetic Forcementioning

confidence: 99%

Theoretical analysis and experimental study of a nonlinear U-shaped bi-directional piezoelectric energy harvester

Shih

2018

Smart Mater. Struct.

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Narrow bandwidth and uni-directional acquisition restrict the application of a conventional cantilever piezoelectric energy harvester. In this study, a magnet-induced nonlinear U-shaped bi-directional piezoelectric harvester is proposed to overcome the shortcomings of the conventional harvester. The U-shaped harvester consists of a beam bent into a U shape with both ends fixed. A pair of piezoelectric plates is attached to the beam for power generation. To introduce nonlinear magnetic force, a magnet is attached to the center of the beam while a pair of magnets are fixed to the base. The theoretical model of the proposed harvester is developed and validated with experimental results. The proposed harvester is investigated in two orthogonal directions of vibration. The proposed harvester shows linear responses in vertical excitations. However, a strong hardening effect can be observed in horizontal excitations especially when the magnet gap is small. It is shown that the hardening effect can improve both the harvesting bandwidth and the output power in horizontal excitations. On the other hand, the resonant frequency of the vertical mode can be increased while that of the horizontal mode is decreased by reducing the magnet gap. This indicates that the magnet gap can be utilized to tune the ratio between the vertical and horizontal resonant frequencies to match the frequencies of vibration sources. Overall, the proposed nonlinear U-shaped harvester demonstrates the capability of bi-directional harvesting and improved performance with the aid of nonlinear magnetic force.

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“…The magnetic force is derived based on fictitious magnetization charges [34]. In this section, the interactive magnetic force between two ring magnets is first derived.…”

Section: Magnetic Forcementioning

confidence: 99%

Theoretical analysis and experimental study of a nonlinear U-shaped bi-directional piezoelectric energy harvester

Shih

2018

Smart Mater. Struct.

View full text Add to dashboard Cite

show abstract

“…In that case the sign of magnetization charges on the surface defines the north and the south poles of the magnet. Magnetization charges have been utilized as a powerful framework for calculation of magnetic fields and forces between magnets of different shape [4][5][6][7][8]. The same approach is being widely applied for a quantitative or qualitative analysis of classroom experiments with magnets, since it relies on an analogy with electrostatics, for example in the description of the force between thin bar magnets [9].…”

Section: Introductionmentioning

confidence: 99%

Ampère currents versus magnetization charges: the theory behind Experimental Problem #2 at the 41st International Physics Olympiad

Ivanov

2018

Eur. J. Phys.

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We analyze theoretically the interaction between a bar magnet and a magnetic ring, as proposed in Experimental Problem #2 at the 41st International Physics Olympiad. The ring is modeled with Ampère currents circulating along its inner and outer circumferences. The bar magnet is represented by two point magnetization charges situated on the ends of the bar. A simple graphical analysis is proposed, which allows one to predict the number, the coordinates, and the stability of the equilibrium positions of the bar magnet. The calculated distance-force dependence is in excellent agreement with the experimental data. We confirm further the validity of our approach by performing experiments with bar magnets of different lengths.

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Magnetic restoring forces on rocking blocks

Syrimi,

Tsiatas,

Tsopelas

2024

Earthq Engng Struct Dyn

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This study investigates the idea of adding an extra magnetic restoring force to a rocking block to improve its overall dynamic performance. The proposed concept ensues by introducing a pair of identical magnets to the rocking block. Both magnets are considered lumped on their respective volume centers and are embedded within the rocking block and the supporting base. When properly magnetized, this pair of magnets provides the rocking block with an extra magnetic restoring force which, although it takes on its maximum value when the two magnets are in contact, decreases as the distance between the two magnets increases. The proposed concept, subjected to pulse‐type base excitations, reveals the inherent problem of magnetic restoring forces. From the overturning spectra of the rocking block, it is found that there are cases where the block fails (overturning) in the presence of magnets, while the same free‐of‐magnets block rocks safely (no overturning) when its own weight acts as the only restoring force. This interesting finding appears to be counterintuitive. Is it possible that by providing additional restoring force the block is “driven” to overturn? This study shows that when the rocking block returns toward the vertical position, the angular velocity, in the presence of magnets, is higher than the angular velocity, in the absence of them. This increase in the angular velocity is a direct outcome of the nature of the magnetic restoring forces, and it is mainly the reason that causes the overturning of the rigid block during its free vibration regime. To mitigate the shortcomings of using magnetic restoring forces, the idea of a semi‐active control of the pair of magnets is introduced and explained in detail. This paper concludes with the advantages and potential disadvantages of the overall performance of rigid blocks in the presence of magnetic restoring forces.

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Interaction Magnetic Force Calculation of Permanent Magnets Using Magnetization Charges and Discretization Technique

Cited by 11 publications

References 14 publications

Theoretical analysis and experimental study of a nonlinear U-shaped bi-directional piezoelectric energy harvester

Theoretical analysis and experimental study of a nonlinear U-shaped bi-directional piezoelectric energy harvester

Ampère currents versus magnetization charges: the theory behind Experimental Problem #2 at the 41st International Physics Olympiad

Magnetic restoring forces on rocking blocks

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