Shear waves with orthogonal polarisations for thickness measurement and crack detection using EMATs

Parra-Raad, Jaime A.; Khalili, Pouyan; Cegla, Frederic

doi:10.1016/j.ndteint.2019.102212

Cited by 22 publications

(10 citation statements)

References 22 publications

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“…The range of the parameters is chosen according to a set of common and realistic specifications. Based on the number of factors and their levels, an orthogonal array L16 (4 5 ) is employed, as shown in Table 2. According to this orthogonal array, sixteen models are established and simulated to obtain the theoretical maximum amplitude e b and lift-off performance k respectively.…”

Section: Optimal Design Of Emats a Orthogonal Test Designmentioning

confidence: 99%

See 1 more Smart Citation

Orthogonal Optimal Design Method for Spiral Coil EMAT Considering Lift-off Effect: A Case Study

2021

IEEE Access

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This paper provided a method to improve the conversion efficiency and lessen the lift-off effect of spiral coil electromagnetic acoustic transducer (EMAT) for some specific situations, for example, irregular sample surface, online inspection and varying coating. Moreover, a new evaluation method for the performance of EMAT is proposed. To study the effect of the structural parameters on the performance of EMAT, the orthogonal test method with five factors and four levels is employed. Consequently, the degree of five factors on the lift-off performance and the theoretical maximum value of amplitude are obtained. The results show almost all factors have an obvious impact on the theoretical maximum value of amplitude, while only the magnet-to-coil distance can affect the lift-off performance effectively. The experiment results well agree with the numerical results, in which the improvement of the lift-off performance and the theoretical maximum value of amplitude is 31.94% and 78.79% respectively. In addition, the conversion efficiency of EMAT is increased by 125% when the lift-off is 1 mm. These imply the performance of spiral coil electromagnetic acoustic transducer is improved dramatically and the detectable lift-off is increased as well.

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Section: Optimal Design Of Emats a Orthogonal Test Designmentioning

confidence: 99%

“…Ultrasonic testing methods are widely used in industrial nondestructive inspection for measurement of thickness, microstructure, defects, plastic strain and so on [1]- [5]. As a type of non-contact ultrasonic transducer, electromagnetic acoustic transducers (EMATs) have many advantages.…”

Section: Introductionmentioning

confidence: 99%

Orthogonal Optimal Design Method for Spiral Coil EMAT Considering Lift-off Effect: A Case Study

2021

IEEE Access

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“…Jaime excited orthogonally polarized shear waves by designing an orthogonal coil. They studied different types of crack defects by finite element (FE) analysis and verified the feasibility of orthogonally polarized shear waves for thickness measurement and crack detection [24]. Trushkevych used a small EMAT inspection system to detect surface corrosion defects, and the detection results showed that defects with a length of 1-11 mm and a depth of 0.5-2 mm could be measured [25].…”

Section: Introductionmentioning

confidence: 99%

Insights into Metal Sheet Novelty Detection via Simulated Electromagnetic Ultrasonic Surface Wave

Zhou

Yang

et al. 2022

Buildings

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Metal sheets have good performance and have been widely used. Different kinds of defects can be generated during the preparation and service of metal plates, which will cause the structural performance of the metal plates to decline, thus requiring structural health monitoring (SHM). This study proposes an electromagnetic ultrasonic (EMUS) surface wave detection technique for metal sheet defects via simulation. The numerical results show that after the excitation parameters of the EMUS transducer are optimized through orthogonal experimental design, the amplitude of the EMUS signal generated is increased by about 80%. The power spectrum density (PSD) of the EMUS response signal is used to detect defects. Compared with the peak-to-peak detection, the accuracy is higher, and the reliability is better. The accuracy of the proposed “central zero-point” method for measuring the time delay of the EMUS signal wave packet is higher than that of the “peak-to-peak amplitude” method and the “vibration starting point” method and is close to the accuracy of the “cross-correlation” method.

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“…Moreover, for the traditional EMAT designs (with a stationary field/permanent magnet), it has been shown that the use of butterfly coils can produce stronger eddy currents and higher Lorentz forces in the test specimen [28]. Parra−Raad et al [29] presented an EMAT that contains two orthogonal co−located butterfly coils. The EMAT can excite two orthogonal polarized shear waves in a metallic material for detecting the presence of crack−like defects in metallic materials.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study and Optimal Design of the Butterfly Coil EMAT for Signal Amplitude Enhancement

Zhang

Liu

Jia

et al. 2022

Sensors

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The low energy conversion efficiency of electromagnetic acoustic transducers (EMATs) is a critical issue in nondestructive testing applications. To overcome this shortcoming, a butterfly coil EMAT was developed and optimized by numerical simulation based on a 2−D finite element model. First, the effect of the structural parameters of the butterfly coil EMAT was investigated by orthogonal test theory. Then, a modified butterfly coil EMAT was designed that consists of three−square permanent magnets with opposite polarity (TSPM−OP) to enhance the signal amplitude. Finally, the signal amplitude obtained from the three types of EMATs, that is, the traditional EMAT, the EMAT optimized by orthogonal test theory, and the modified EMAT with TSPM−OP, were analyzed and compared. The results show that the signal amplitude achieved by the modified butterfly coil EMAT with TSPM−OP can be increased by 4.97 times compared to the traditional butterfly coil EMAT.

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Shear waves with orthogonal polarisations for thickness measurement and crack detection using EMATs

Cited by 22 publications

References 22 publications

Orthogonal Optimal Design Method for Spiral Coil EMAT Considering Lift-off Effect: A Case Study

Orthogonal Optimal Design Method for Spiral Coil EMAT Considering Lift-off Effect: A Case Study

Insights into Metal Sheet Novelty Detection via Simulated Electromagnetic Ultrasonic Surface Wave

Numerical Study and Optimal Design of the Butterfly Coil EMAT for Signal Amplitude Enhancement

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