Unidirectional Shear Horizontal Wave Generation With Side-Shifted Periodic Permanent Magnets Electromagnetic Acoustic Transducer

Kubrusly, Alan C.; Kang, Lei; Dixon, Steve

doi:10.1109/tuffc.2020.3027246

Cited by 23 publications

(8 citation statements)

References 24 publications

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“…A unidirectional PPM EMAT is essentially two standard PPM EMATs overlapped and integrated into each other. The magnet array of the top EMAT is side shifted a quarter wavelength ahead of the bottom EMAT [ 21 ]. Each EMAT has a coil, which is pulsed separately from the other; the top EMAT coil,

is pulsed 90° after the bottom coil,

, which causes the two forward propagating waves to constructively interfere and the backward propagating waves to destructively interfere, essentially eliminating the wave propagation on one side [ 21 ].…”

Section: Mobile Robotic Transducer Designmentioning

confidence: 99%

“…Kubrusly et al [ 21 ] demonstrate a side-shifted magnet array, which equates to two PPM EMATs merged and offset; the two coils in this EMAT are pulsed 90° apart, resulting in single sided generation with small backward side-lobes. [ 22 ] This demonstrates a dual-linear coil array rather than the traditional racetrack design, whereby multiple magnet arrays are individually wrapped in wire from one of two coils, which are pulsed with 90° separation creating single sided generation.…”

Section: Introductionmentioning

confidence: 99%

“…The resultant wavelength is, however, doubled, making it more suited to low frequencies [ 23 ]. The revised side-shifted design of [ 21 ] improved the radial pattern by altering the racetrack coil shape to a loop under increased magnet arrays.…”

Section: Introductionmentioning

confidence: 99%

“…Following on, this study will look to apply the optimisation method to a unidirectional side-shifted PPM EMAT, where two coils are pulsed independently with one pulse 90° out of phase from the other, similar to that in [ 21 ], except that this study is optimising PCB racetrack coils and magnet arrays with a focus for use in mobile robotics. In addition, a receiver EMAT will be constructed; this will then be packaged together with the transmitter as one small unit for ease of deployment onto a mobile robotic system.…”

Section: Introductionmentioning

confidence: 99%

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Design and Manufacture of an Optimised Side-Shifted PPM EMAT Array for Use in Mobile Robotic Localisation

McMillan

Hampson

Tabatabaeipour

et al. 2023

Sensors

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Guided wave Electro Magnetic Acoustic Transducers (EMATs) offer an elegant method for structural inspection and localisation relative to geometric features, such as welds. This paper presents a Lorentz force EMAT construction framework, where a numerical model has been developed for optimising Printed Circuit Board (PCB) coil parameters as well as a methodology for optimising magnet array parameters to a user’s needs. This framework was validated experimentally to show its effectiveness through comparison to an industry built EMAT. The framework was then used to design and manufacture a Side-Shifted Unidirectional Periodic Permanent Magnet (PPM) EMAT for use on a mobile robotic system, which uses guided waves for ranging to build internal maps of a given subject, identifying welded sections, defects and other structural elements. The unidirectional transducer setup was shown to operate in simulation and was then manufactured to compare to the bidirectional transmitter and two-receiver configurations on a localisation system. The unidirectional setup was shown to have clear benefits over the bidirectional setup for mapping an unknown environment using guided waves as there were no dead spots of mapping where signal direction could not be interpreted. Additionally, overall package size was significantly reduced, which in turn allows more measurements to be taken within confined spaces and increases robotic crawler mobility.

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is pulsed 90° after the bottom coil,

Section: Mobile Robotic Transducer Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Design and Manufacture of an Optimised Side-Shifted PPM EMAT Array for Use in Mobile Robotic Localisation

McMillan

Hampson

Tabatabaeipour

et al. 2023

Sensors

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show abstract

“…They control the frequency bandwidth by increasing the number of cycles of the excited signal, which helps to focus the energy. Another group led by Dixon [15] [16] investigated the mode conversion effect of higher-order modes over the symmetric and non-symmetric discontinuities. They explain the symmetric mode converse to symmetric mode with symmetric discontinuities in the plate.…”

Section: Introductionmentioning

confidence: 99%

Investigation of mode conversion of SH waves at the welded tabular ends of a fuel storage tank

Gautam

Wen

Yin

et al. 2023

Health Monitoring of Structural and Biological Systems XVII

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Storage tanks are an essential part of petrochemical plants. Most storage tanks are cylindrical, and the base plate is welded at the edge. The bottom plate of the tank is eventually exposed to the environment and soil, leading to corrosion over time. The tank bottom metal loss is one of the defects caused by corrosion initiated by the welded tubular end of the storage tank. Inspecting the storage tank corrosion defect is imperative to avoid undesirable losses. In recent years, the electromagnetic acoustic transducer (EMAT) has become an effective non-contact and non-couplant inspection tool for applying Non-destructive Testing (NDT) & structural health monitoring (SHM). Generally, the guided wave method is preferred to inspect the defect by reflecting propagating wave (SH) modes. It has been observed that the reflected wave modes converse into different modes at a certain reflection angle due to the defect orientations and the welded ends. Due to mode conversion, identifying the defect position with SH wave modes is challenging. This study investigates the influence of mode conversion on the reflected wave from the welded tabular ends of the storage tank. A numerical model has been developed to investigate the SH wave propagation, reflection, and mode conversion due to defects and welded tabular ends. Further, an experiment has been performed with a chevron PPM-EMAT for generating SH wave to validate and compare the simulation results.

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Numerical Investigation of Application of Unidirectional Generation to Improve Signal Interpretation of Circumferential Guided Waves in Pipes for Defect Detection

Kubrusly

Kang

Weid

et al. 2022

Lecture Notes in Civil Engineering

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Unidirectional Shear Horizontal Wave Generation With Side-Shifted Periodic Permanent Magnets Electromagnetic Acoustic Transducer

Cited by 23 publications

References 24 publications

Design and Manufacture of an Optimised Side-Shifted PPM EMAT Array for Use in Mobile Robotic Localisation

Design and Manufacture of an Optimised Side-Shifted PPM EMAT Array for Use in Mobile Robotic Localisation

Investigation of mode conversion of SH waves at the welded tabular ends of a fuel storage tank

Numerical Investigation of Application of Unidirectional Generation to Improve Signal Interpretation of Circumferential Guided Waves in Pipes for Defect Detection

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