Finite simulation of weld inspection using time-of-flight diffraction method based on laser ultrasonic

2019 ◽  
Author(s):  
Jin Yang ◽  
Lin Luo ◽  
Kai Yang ◽  
Jinlong Li ◽  
Xiaorong Gao
Keyword(s):  
Time Of Flight ◽  
Diffraction Method ◽  
Laser Ultrasonic ◽  
Time Of Flight Diffraction ◽  
Weld Inspection

Defect Sizing in Pipeline Welds: What Can We Really Achieve?

2004 ◽  
Author(s):  
Michael Moles
Keyword(s):  
Fracture Mechanics ◽  
Time Of Flight ◽  
Spot Size ◽  
Height Measurement ◽  
Beam Spot ◽  
Analysis Techniques ◽  
Time Of Flight Diffraction ◽  
Beam Spot Size ◽  
Weld Inspection ◽  
Focused Transducers

Pipelines are now using Fitness-For-Service (FFS) for accept/reject of weld defects. FFS requires accurate measurement of defect height for Fracture Mechanics assessments. The standard pipeline weld inspection technique of radiography is incapable of such measurements. However, the newer technique of ultrasonics can measure defect height, in principle. Initially ultrasonic amplitude methods were used for height measurement, but these proved unreliable. Now diffraction methods, especially Time-Of-Flight-Diffraction (TOFD), are being used in conjunction. This paper reviews previous work — mainly large nuclear studies like PISC II — and published pipeline sizing studies. The best nuclear sizing was within a few millimetres, using diffraction. In contrast to nuclear, pipeline AUT uses zone discrimination, focused transducers, much thinner material and simpler analysis techniques. Current accuracies are typically ± 1 mm (terminology undefined), which correlates with the beam spot size and typical weld pass. Requests for accuracies of ± 0.3 mm are probably unachievable, though future R&D should significantly improve pipeline sizing.

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

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.

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

Measurement ◽  
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

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

2012 ◽  
Vol 22 (11) ◽  
pp. 2679-2684 ◽  
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

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

2004 ◽  
Vol 261-263 ◽  
pp. 987-992 ◽  
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.

scholarly journals Tangential Homology for Defect Detection in the Time of Flight Diffraction Method (TOFD)

PAMM ◽  
2016 ◽  
Vol 16 (1) ◽  
pp. 619-620
Author(s):  
Jose F. Cuenca ◽  
Armin Iske ◽  
Patrick A. Labud ◽  
Oliver Nemitz
Keyword(s):  
Defect Detection ◽  
Time Of Flight ◽  
Diffraction Method ◽  
Time Of Flight Diffraction

Determination of the structure of Y(HCOO)3 by the neutron time-of-flight diffraction method

1986 ◽  
Vol 59 (2) ◽  
pp. 95-97 ◽  
Author(s):  
V.A. Trunov ◽  
V.A. Kudryashev ◽  
A.P. Bulkin ◽  
V.A. Ulyanov ◽  
A.A. Loshmanov ◽  
...  
Keyword(s):  
Time Of Flight ◽  
Diffraction Method ◽  
Time Of Flight Diffraction ◽  
Neutron Time
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