Experiences in the Use of Guided Ultrasonic Waves to Scan Structures

Thompson, R. B.

doi:10.1007/978-1-4615-5947-4_16

Cited by 10 publications

(9 citation statements)

References 3 publications

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“…In short-range applications, guided waves are used to obtain localized data about a specimen in situations where conventional ultrasonic techniques cannot be applied. Examples include air-coupled inspection of composites [3], Rayleigh wave detection of surface discontinuities in artillery shells [4], and acoustic microscopy [5]. In medium-and long-range applications, the reason for using guided waves is to increase the amount of a structure that can be inspected from one location, hence reducing inspection costs and sometimes enabling inaccessible regions in a structure to be tested.…”

Section: Introductionmentioning

confidence: 99%

Omnidirectional guided wave inspection of large metallic plate structures using an EMAT array

Wilcox

Lowe

Cawley

2005

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

132

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The design of an electromagnetic acoustic transducer (EMAT) array device for the inspection of large areas of metallic plate-like structures using the S0 guided wave mode is described. The reasons for using the S0 mode are discussed and it is shown how the choice of mode determines the nature of the EMAT array elements. A novel array construction technique is shown to be necessary whereby the EMAT coils for adjacent elements are overlapped in order to achieve the required element density. Results are presented that illustrate the operation of the device on steel and aluminum plate specimens in the thickness range from 5 to 10 mm. An area of at least 10 m 2 can be inspected from a single location. Spurious signals in the results are caused both by the unwanted A0 mode and by S0 sidelobes, the latter occurring at the same radial distance from the array as the genuine S0 signal from a reflector, but in the wrong direction. The signal-to-coherent noise performance of the complete system is determined by the amplitude ratio of the largest genuine S0 signal to the largest spurious signal. This is typically around 30 dB. The sensitivity of the device to artificial defects and genuine corrosion patches is demonstrated and the limitations of its operation are discussed. The feasibility of using the device with the S1 guided wave mode to inspect a 20 mm thick plate is also demonstrated.

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Section: Introductionmentioning

confidence: 99%

Omnidirectional guided wave inspection of large metallic plate structures using an EMAT array

Wilcox

Lowe

Cawley

2005

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

132

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“…The Lorentz-force mechanism was studied by many researchers (Gaerttne et al, 1969;Beissner, 1976;Kawashima, 1976;Maxfield and Fortunko, 1983; Thompson, 1990). We summarize their studies here.…”

Section: Lorentz Forcementioning

confidence: 92%

“…The EMAT designing and instrumentation were facilitated by the physical models, wh ich were best described later by Thompson (1990) and recently extended by Ogi (1997a). Drawing much on his previous work starting in 1973, Thompson provided a general framework and analytical formalism covering both of the Lorentz-force and magnetostrictive coupling mechanisms.…”

Section: Brief Historical Sketch Of Ematmentioning

confidence: 99%

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EMATs for Science and Industry

Hirao¹,

Ogi²

2003

264

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“…This means that a guide wave can inspect alarge area [3]. For example, inspecting a pipe [4], rail [5], and cold rolled steel [6] using a guide wave has been tried.…”

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confidence: 99%

Study of an Omnidirectional Guide Wave Sensor Using an EMAT

Murayama¹,

Iwaya²

2017

JST

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Nondestructive inspection of structures is important for ensuring the safety of the social infrastructure. Among them, the ultrasonic inspection method plays a role as a major technology. However, when examining a huge structure, the inspection time tends to be very long. Therefore, a system for transmitting and receiving ultrasonic waves in all directions from the ultrasonic sensor has been constructed. Several types of ultrasonic sensors using this concept have already been devised, but since the ultrasonic energy is dispersed in all directions, there is a problem that a sufficient detection performance cannot be ensured, especially when the thickness of the material to be inspected becomes thick. Therefore, we developed a highly sensitive omnidirectional ultrasonic sensor utilizing the resonance phenomenon of the ultrasonic wave propagating in the thickness direction. The omnidirectional ultrasonic system also consists of an electromagnetic ultrasonic transducer (EMAT) using a circular magnet. It is possible to inspect the plate thickness from 0.3 mm to 10 mm and the inspection range of the diameter of 300 mm around the sensor by the developed system. It is indicated that the developed system allows the highspeed inspection of huge structures.

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Experiences in the Use of Guided Ultrasonic Waves to Scan Structures

Cited by 10 publications

References 3 publications

Omnidirectional guided wave inspection of large metallic plate structures using an EMAT array

Omnidirectional guided wave inspection of large metallic plate structures using an EMAT array

EMATs for Science and Industry

Study of an Omnidirectional Guide Wave Sensor Using an EMAT

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