Influences of magnetic circuit structure of magnetostrictive guided wave transducer on the homogeneity of bias magnetic field

2010 ◽  
Vol 33 (1-2) ◽  
pp. 581-588 ◽  
Author(s):  
Xiaochun Song ◽  
Zhisheng Jin ◽  
Hao Yu
Keyword(s):  
Magnetic Field ◽  
Magnetic Circuit ◽  
Guided Wave ◽  
Bias Magnetic Field ◽  
Circuit Structure ◽  
Wave Transducer

A flexural mode guided wave transducer for pipes based on magnetostrictive effect

2020 ◽  
Vol 64 (1-4) ◽  
pp. 335-342
Author(s):  
Yun Sun ◽  
Jiang Xu ◽  
Chaoyue Hu ◽  
Guang Chen ◽  
Yunfei Li
Keyword(s):  
Magnetic Field ◽  
Guided Waves ◽  
Permanent Magnets ◽  
Wave Structure ◽  
Guided Wave ◽  
Circumferential Direction ◽  
Bias Magnetic Field ◽  
Flexural Mode ◽  
Axial Crack ◽  
Wave Transducer

The flexural mode guided waves of pipes which are sensitive the axial crack and suitable for wave focused gain more attention recently. In this paper, a non-contact flexural mode guided wave transducer based on magnetostrictive effect is provided for pipes. Based on the magnetostrictive transduction principle and the wave structure of the flexural mode guided wave, the sensing method for generating and receiving the flexural mode guided waves based on magnetostrictive effect is obtained. According to the theoretical analysis, a non-contact magnetostrictive transducer for F (3, m) mode guided waves is given. Six permanent magnets which are evenly distributed in the circumferential direction of the pipe and arranged in opposite polarities are employed to provide the bias magnetic field in the circumferential direction. A solenoid coil is employed to induce the axial alternating magnetic field. The bias magnetic field distribution of the flexural mode guided wave in the pipeline is analyzed by the finite element simulation. The mode of the transduction guided wave in the pipe is verified by experiments based on the dispersion curves.

scholarly journals Signal Strength Enhancement of Magnetostrictive Patch Transducers for Guided Wave Inspection by Magnetic Circuit Optimization

2019 ◽  
Vol 9 (7) ◽  
pp. 1477 ◽  
Author(s):  
Jianjun Wu ◽  
Zhifeng Tang ◽  
Keji Yang ◽  
Fuzai Lv
Keyword(s):  
Magnetic Field ◽  
Magnetic Circuit ◽  
Energy Conversion Efficiency ◽  
Wave Generation ◽  
Guided Wave ◽  
Shear Mode ◽  
Circuit Optimization ◽  
Affecting Factors ◽  
Long Distance ◽  
Dynamic Magnetic Field

Magnetostrictive patch transducers (MPT) with planar coils are ideal candidates for shear mode generation and detection in pipe and plate inspection with the advantages of flexibility, lightness and good directivity. However, the low energy conversion efficiency limits the application of the MPT in long distance inspection. In this article, a method for the enhancement of the MPT was proposed by dynamic magnetic field optimization using a soft magnetic patch (SMP). The SMP can reduce the magnetic resistance of the magnetic circuit, which increases the dynamic magnetic field intensity in the magnetostrictive patch during wave generation and restricts the induced dynamic magnetic field within the area around the coils for sensing during wave detection. Numerical simulations carried out at different frequencies verified the improvement of the dynamic magnetic fields by the SMP and influence of different affecting factors. The experimental validations of the signal enhancement in wave generation and detection were performed in an aluminum plate. The amplitude magnification could reach 12.7 dB when the MPTs were covered by the SMPs. Based on the numerical and experimental results, the SMP with a large relative permeability and thickness and close fitting between the SMP and coils were recommended when other application conditions were met.

High efficiency guided-wave magnetooptic Bragg cell modulator using nonuniform bias magnetic field

1997 ◽  
Vol 71 (25) ◽  
pp. 3715-3717 ◽  
Author(s):  
C. S. Tsai ◽  
Y. S. Lin ◽  
J. Su ◽  
S. R. Calciu
Keyword(s):  
Magnetic Field ◽  
High Efficiency ◽  
Guided Wave ◽  
Bias Magnetic Field

Development of Permanent Magnet Generator Used for Magnetic Field Assisted Micro Electroforming Technology

2014 ◽  
Vol 936 ◽  
pp. 1716-1719 ◽  
Author(s):  
Hui Juan Li ◽  
Ping Mei Ming ◽  
Xiao Hui Bao ◽  
Xiao Dong Zhang ◽  
Xiang Yang Bi
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Uniform Magnetic Field ◽  
Magnetic Circuit ◽  
Geometrical Shape ◽  
Electroforming Process ◽  
Fundamental Process ◽  
Circuit Structure ◽  
Permanent Magnet Generator

To provide appropriately high and uniform magnetic field for micro electroforming process, a permanent magnet generator was specially developed which based on the fundamental process requirements. On the basis of determining the number of permanent magnet combinations numerically. Mainly, the geometrical shape of the permanent magnet blocks and magnetic circuit structure were optimized, and then the working gap regulating mechanism for this generator was designed. Utilizations indicated that the developed generator met the requirements well.

scholarly journals The Research and Application of MRF Magnetic Circuit Design

2015 ◽  
Vol 9 (1) ◽  
pp. 241-245
Author(s):  
Yuan Shu ◽  
Ren Hongjuan ◽  
Luo Yiping
Keyword(s):  
Magnetic Field ◽  
Circuit Design ◽  
Test Bench ◽  
Magnetic Circuit ◽  
Magnetorheological Fluid ◽  
Theoretical Research ◽  
Circuit Structure ◽  
Magneto Rheological

In this paper, the lord magnetic field of MRF and its circuit design are mainly expounded, according to the loading ways of magnetic field and the magnetic circuit design plans of magneto-rheological fluid devices at present, the general form and characteristics are summarized. In addition, a kind of magneto-rheological fluid dynamometer is proposed in this paper, in terms of its magnetic circuit structure, a magnetic-field-lord test bench about magnetorheological fluid is designed; a preliminary theoretical research is also given in order to improve the performance of magneto-rheological fluid dynamometer.

Simulation Study on Magnetic Field Characteristics of High Magnetic Field Intensity Permanent Magnet Magnetic Filter

2010 ◽  
Vol 97-101 ◽  
pp. 2622-2627
Author(s):  
Hong Guang Jiao ◽  
Peng Liu ◽  
Zhan Xu Tie
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Magnetic Circuit ◽  
Magnetic Filter ◽  
Circuit Structure ◽  
Magnetic Induction Intensity ◽  
The Magnetic Field ◽  
Outside Diameter

To solve the conflict between separation space and magnetic field intensity, an original magnetic circuit structure system of permanent magnet magnetic filter is designed by utilizing multi-dimensional magnet extrusion technologies, with multi-block NdFeB magnets of different structures and magnetization directions. The inside diameter of the ring magnets and ring soft iron is taken as separating space. To inspect the distribution of the magnetic field characteristics of magnetic circuit system, mathematical model is established, and the designed magnetic circuit system is simulated, taking advantage of the electromagnetic software Magnet. The simulation results show that a larger separating space and higher background magnetic density can be achieved simultaneously by means of the organic magnetic circuit system design, when the thickness of ring soft iron is 4mm and the diameter ratio (outside diameter to the diameter) of ring magnets is 10/3. The highest magnetic induction intensity of 29.2 mm separating space is 1.5T, which provides the basis for permanent magnet magnetic circuit design.

Ferrofluid lubrication for ball bearings to avoid starvation

2020 ◽  
Vol 72 (10) ◽  
pp. 1227-1231
Author(s):  
Mancheng Xu ◽  
Guanghu Jin ◽  
Qingwen Dai ◽  
Wei Huang ◽  
Xiaolei Wang
Keyword(s):  
Magnetic Field ◽  
Service Life ◽  
Peer Review ◽  
Design Methodology ◽  
Ball Bearing ◽  
Magnetic Circuit ◽  
Ball Bearings ◽  
Rolling Bearings ◽  
Content Type ◽  
Circuit Structure

Purpose This paper aims to prevent oil starvation and improve the service life of the rolling bearings. Design/methodology/approach A thrust ball bearing with magnetic circuit structure is proposed for ferrofluid lubrication. With the aid of magnetic field, ferrofluid can be maintained in the contact area of rolling bodies to delay lubricant loss. Experiments are performed to ensure the validity of the designed bearing. Findings Compared with conventional lubricant, service life of the ferrofluid lubricated bearing can be prolonged under magnetic field. In addition, with a proper magnetic field distribution, lubricant starvation may be limited under the conditions of present experiments. Originality/value This work provides a method to control the starved lubrication of rolling bearings with restricted lubricant supply. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0132/

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