Study of the ultrasonic creeping wave propagation over a concave metal surface

Creeping ultrasonic waves are used in echo flaw detection of near-surface and near-bottom zones of metal products of plane-parallel or cylindrical shape. The creeping (lateral) waves are also used in testing products by the time-of-flight diffraction method as the earliest (reference) signal, followed by the useful signals of waves diffracted on metal discontinuities. The purpose of this study is to evaluate the ability of the creeping wave to propagate over a concave metal surface. We have studied experimentally the attenuation of the amplitude of a creeping wave with the distance upon wave propagation over concave metal surfaces of different radii. The velocity of propagation of the creeping wave does not depend on the radius of curvature and equals to the velocity of the bulk longitudinal wave. The results obtained provide the possibility of using the time-of-flight diffraction method in control of the objects with concave surfaces, in particular, for in-tube testing.

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Defect detection of partially complete SAW and TIG welds using the ultrasonic time-of-flight diffraction method

10.1117/12.302549 ◽

1998 ◽

Cited By ~ 1

Author(s):

Shaun W. Lawson ◽

Gary R. Bonser

Keyword(s):

Defect Detection ◽

Time Of Flight ◽

Diffraction Method ◽

Time Of Flight Diffraction ◽

Ultrasonic Time

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CREEPING SURFACE LONGITUDINAL ACOUSTIC WAVE: MAIN PROPERTIES AND APPLICATION POSSIBILITIES

Kontrol Diagnostika ◽

10.14489/td.2021.07.pp.004-012 ◽

2021 ◽

pp. 4-12

Author(s):

V. G. Shevaldykin

Keyword(s):

Critical Angle ◽

Flaw Detection ◽

Ultrasonic Signal ◽

Ultrasonic Waves ◽

Concave Surface ◽

Ultrasonic Tomography ◽

Transverse Waves ◽

Near Surface ◽

The Third ◽

Creeping Wave

Creeping ultrasonic waves have long been successfully used for flaw detection of near-surface and near-bottom zones of metal products. However, due to the fact that the creeping wave generates a lateral transverse wave directed into the metal volume at the third critical angle, it is also possible to test internal defects in principle. At known velocities of propagation of longitudinal and transverse waves in the metal, the third critical angle is easily calculated. Therefore, the time of propagation of the ultrasonic signal along any trajectory between points on the surface and in the volume of the metal can be calculated. Usually, creeping waves are used to test products of plane-parallel shape. There are no cases of their application on curved surfaces in the literature. It is possible that the creeping wave can also propagate over a concave surface. The aim of the article is to test experimentally new ways of using creeping waves. The propagation trajectories of the creeping and lateral transverse waves were studied on a steel plate. The time of passage of the ultrasonic signal along such trajectories of different lengths was measured, and the measurement results were compared with the calculated time values. The measured and calculated values coincided with accuracy sufficient for the coherent accumulation of echo signals that passed through the metal part of the path by the creeping wave and another part of the path by the lateral transverse wave.The propagation of the creeping wave over a concave surface was studied on a steel sample with cylindrical faces of different radii. As a result, it turned out that on a concave surface, the creeping wave propagates at the same speed of longitudinal waves as on a flat surface, but it decays much more strongly with distance. Studies have shown that creeping waves can be used in ultrasonic tomography, where a preliminary calculation of the propagation trajectories of ultrasonic signals is required. The propagation of creeping waves over concave surfaces extends the capabilities of the TOFD method to the area of intube testing

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Time-of-flight diffraction method for joint with linear misalignment

Insight - Non-Destructive Testing and Condition Monitoring ◽

10.1784/insi.2021.63.11.654 ◽

2021 ◽

Vol 63 (11) ◽

pp. 654-658

Author(s):

Y Kurokawa ◽

T Kawaguchi ◽

H Inoue

Keyword(s):

Exact Solution ◽

Approximate Solution ◽

Geometric Model ◽

Time Of Flight ◽

Diffraction Method ◽

Approximate Solutions ◽

Weld Joints ◽

Time Of Flight Diffraction ◽

Flaw Sizing ◽

Probe Spacing

The time-of-flight diffraction (TOFD) method is known as one of the most accurate flaw sizing methods among the various ultrasonic testing techniques. However, the standard TOFD method cannot be applied to weld joints with linear misalignment because of its basic assumptions. In this study, a geometric model of the TOFD method for weld joints with linear misalignment is introduced and an exact solution for calculating the flaw tip depth is derived. Since the exact solution is extremely complex, a simple approximate solution is also derived assuming that the misalignment is sufficiently small relative to the probe spacing and the flaw tip depth. The error in the approximate solution is confirmed to be negligible if the assumptions are satisfied. Numerical simulations are conducted to assess the flaw sizing accuracy of both the exact and approximate solutions considering the constraint of the probe spacing and the influence of the excess metal shape. Finally, experiments are conducted to prove the applicability of the proposed method. As a result, the proposed method is proven to enable accurate flaw sizing of weld joints with linear misalignment.

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A metrological approach to the time of flight diffraction method (ToFD)

Measurement ◽

10.1016/j.measurement.2020.108298 ◽

2021 ◽

Vol 167 ◽

pp. 108298

Author(s):

R.C. Mayworm ◽

A.V. Alvarenga ◽

R.P.B. Costa-Felix

Keyword(s):

Time Of Flight ◽

Diffraction Method ◽

Time Of Flight Diffraction ◽

Metrological Approach

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In-situ quantitative monitoring of fatigue crack using fastest time of flight diffraction method

Transactions of Nonferrous Metals Society of China ◽

10.1016/s1003-6326(11)61517-3 ◽

2012 ◽

Vol 22 (11) ◽

pp. 2679-2684 ◽

Cited By ~ 3

Author(s):

Chao-liang DU ◽

Yi-shou WANG ◽

Dong-yue GAO ◽

Ke-hai LIU ◽

Xin-lin QING

Keyword(s):

Fatigue Crack ◽

Time Of Flight ◽

Diffraction Method ◽

Time Of Flight Diffraction ◽

Quantitative Monitoring

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Time of Flight Diffraction Method Using Laser Ultrasound for Noncontact Flaw Height Measurement

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.261-263.987 ◽

2004 ◽

Vol 261-263 ◽

pp. 987-992 ◽

Cited By ~ 1

Author(s):

T. Mihara ◽

Y. Otsuka ◽

H. Cho ◽

Kazushi Yamanaka

Keyword(s):

Aluminum Alloy ◽

Shear Wave ◽

Time Of Flight ◽

Diffraction Method ◽

Laser Ultrasound ◽

Height Measurement ◽

Alloy Plate ◽

Time Of Flight Diffraction ◽

Probe Distance ◽

Aluminum Alloy Plate

We developed a laser TOFD (Time of flight diffraction) algorithm which utilizes not only longitudinal wave but also shear wave. This algorithm made it possible to obtain accurate flaw depth without knowing the specimen velocity and probe distance previously. We constructed the laser TOFD system and applied it to estimate the slit depth of aluminum alloy plate. Time of flight of lateral wave, flaw tip diffraction waves and mode converted shear wave at flaw tip were used to estimate the slit depth using new algorithm.

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