3-D modeling and analysis of meander-line-coil surface wave EMATs

Wang, Shujuan; Kang, Lei; Li, Zhichao; Zhai, Guofu; Zhang, Long

doi:10.1016/j.mechatronics.2011.04.001

Cited by 47 publications

(34 citation statements)

References 16 publications

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“…An EMAT sensor typically consists of a permanent magnet providing a large static magnetic field and a coil carrying an alternating current which is placed next to the test piece [19][20][21]. There are two EMAT interactions which can produce ultrasound: magnetostriction for magnetic materials and the Lorentz force mechanism for conducting metallic materials [18,20,22].…”

Section: Introductionmentioning

confidence: 99%

Simulation of an Electromagnetic Acoustic Transducer Array by Using Analytical Method and FDTD

et al. 2016

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Previously, we developed a method based on FEM and FDTD for the study of an Electromagnetic Acoustic Transducer Array (EMAT). This paper presents a new analytical solution to the eddy current problem for the meander coil used in an EMAT, which is adapted from the classic Deeds and Dodd solution originally intended for circular coils. The analytical solution resulting from this novel adaptation exploits the large radius extrapolation and shows several advantages over the finite element method (FEM), especially in the higher frequency regime. The calculated Lorentz force density from the analytical EM solver is then coupled to the ultrasonic simulations, which exploit the finite-difference time-domain (FDTD) method to describe the propagation of ultrasound waves, in particular for Rayleigh waves. Radiation pattern obtained with Hilbert transform on time-domain waveforms is proposed to characterise the sensor in terms of its beam directivity and field distribution along the steering angle, which can produce performance parameters for an EMAT array, facilitating the optimum design of such sensors.

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Section: Introductionmentioning

confidence: 99%

Simulation of an Electromagnetic Acoustic Transducer Array by Using Analytical Method and FDTD

et al. 2016

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“…It should be noted that, for the EMATs modelling, the dynamic magnetic field was neglected due to the small excitation AC current (5 A) used in this work; The effect of the dynamic magnetic field generated by the meander-line-coil must be considered when the excitation current is large as it is one of the mechanisms to generate ultrasound waves; [32] suggested, when the excitation exceeds 528.9 A, the dynamic magnetic field plays a more significant role than the static magnetic field, which is generated by the permanent magnet. Therefore, the vertical forces, which are generated by the dynamic magnetic field and the eddy current, are neglected in this work.…”

Section: Emat-em Modellingmentioning

confidence: 99%

“…The reason we choose a dense source points is that lots of source points guarantee the wave interference' integrity. Shear waves' velocity C s 3.14 mm/μs [32] Rayleigh waves' velocity C R 2.93 mm/μs [32] The meander-line-coil is located on the centre of the aluminium plate, so the whole EMAT-UT model is symmetrical with y=300 mm; in order to improve the modelling time, only the left half of the geometry is modelled. Only the area, y from 0 to 250 mm, is presented where the signals are significant.…”

Section: Emat-ut Modellingmentioning

confidence: 99%

Directivity analysis of meander-line-coil EMATs with a wholly analytical method

et al. 2017

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This paper presents the simulation and experimental study of the radiation pattern of a meander-line-coil EMAT. A wholly analytical method, which involves the coupling of two models: an analytical EM model and an analytical UT model, has been developed to build EMAT models and analyse the Rayleigh waves' beam directivity. For a specific sensor configuration, Lorentz forces are calculated using the EM analytical method, which is adapted from the classic Deeds and Dodd solution. The calculated Lorentz force density are imported to an analytical ultrasonic model as driven point sources, which produce the Rayleigh waves within a layered medium. The effect of the length of the meander-line-coil on the Rayleigh waves' beam directivity is analysed quantitatively and verified experimentally.

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“…Wang et al [99] proposed an enhancement to the previous FEA models of an EMAT, taking into account a dynamic magnetic field in a meander coil, coming up with the distribution of eddy currents, static magnetic field, Lorentz forces and resultant elastic waves. The FEA results corroborated with an experiment.…”

Section: Emats (Electromagnetic Acoustic Transducers)mentioning

confidence: 99%

Finite Element Method Applied in Electromagnetic NDTE: A Review

Augustyniak

Usarek

2016

J Nondestruct Eval

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The paper contains an original comprehensive review of finite element analysis (FEA) applied by researchers to calibrate and improve existing and developing electromagnetic non-destructive testing and evaluation techniques, including but not limited to magnetic flux leakage (MFL), eddy current testing, electromagnetic-acoustic transducers (EMATs). Premium is put on the detection and modelling of magnetic field, as the vast majority of ENDT involves magnetic induction, either as a primary variable MFL or a complementary phenomenon (EC, EMATs). FEA is shown as a fit-for-purpose tool to design, understand and optimise ENDT systems, or a Reference for other modelling algorithms. The review intentionally omits the fundamentals of FEA and detailed principles of NDT. Strain-stress FEA applications in NDT, especially in ultrasonography and hole-drilling methodology, deserve as well a separate study.

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3-D modeling and analysis of meander-line-coil surface wave EMATs

Cited by 47 publications

References 16 publications

Simulation of an Electromagnetic Acoustic Transducer Array by Using Analytical Method and FDTD

Simulation of an Electromagnetic Acoustic Transducer Array by Using Analytical Method and FDTD

Directivity analysis of meander-line-coil EMATs with a wholly analytical method

Finite Element Method Applied in Electromagnetic NDTE: A Review

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