Group modes based time reversal imaging algorithms for pipeline inspection using ultrasonic guided waves

2012 ◽  
Vol 131 (4) ◽  
pp. 3350-3350
Author(s):  
Weichang Li ◽  
Shuntao Liu ◽  
Limin Song
Keyword(s):  
Time Reversal ◽  
Guided Waves ◽  
Ultrasonic Guided Waves ◽  
Pipeline Inspection ◽  
Imaging Algorithms

Time Reversal Technique for Ultrasonic Guided Wave Inspection

2006 ◽  
Vol 321-323 ◽  
pp. 776-779
Author(s):  
Hak Joon Kim ◽  
Sung Jin Song ◽  
Jung Ho Seo ◽  
Jae Hee Kim ◽  
Heung Seop Eom
Keyword(s):  
Time Delay ◽  
Power Plant ◽  
Time Reversal ◽  
Nuclear Power ◽  
Guided Waves ◽  
Performance Enhancement ◽  
Guided Wave ◽  
Ultrasonic Waves ◽  
Ultrasonic Guided Waves ◽  
Ultrasonic Guided Wave

For the long range inspection of structures in nuclear power plant using array transducers, it is necessary to focus waves on defects under interrogation. To take care of such a need, in this study we adopt a time reversal technique that is claimed to be very robust to focus ultrasonic waves on defects. Specifically, we calculate the appropriate time delay using the time reversal technique and re-generate ultrasonic guided waves that are focusing to an interrogated defect with the calculated time delay. In this paper, we describe the principle of the time reversal technique briefly and present the performance enhancement obtained by the time reversal techniques.

A Study on the Time Reversal Method for Focusing Ultrasonic Guided Waves Using Array Transducers

2007 ◽  
Author(s):  
Hak-Joon Kim ◽  
Jong-Ho Seo ◽  
Sung-Jin Song ◽  
Jae-Hee Kim ◽  
Heung-Seop Eom
Keyword(s):  
Time Reversal ◽  
Guided Waves ◽  
Ultrasonic Guided Waves

Signal Enhancement of Ultrasonic Guided Waves Using Time Reversal Technique

2011 ◽  
Vol 282-283 ◽  
pp. 589-592
Author(s):  
Hai Yan Zhang ◽  
Jian Bo Yu ◽  
Xian Hua Chen
Keyword(s):  
Time Reversal ◽  
Guided Waves ◽  
Detection Efficiency ◽  
Single Mode ◽  
Element Model ◽  
Signal Enhancement ◽  
Ultrasonic Guided Waves ◽  
Center Frequency ◽  
Detection Capability ◽  
Reflected Wave

Signal enhancement of ultrasonic guided waves is studied using time reversal technique. The defect in pipe is detected by activating single mode guided waves L(0,2) at the center frequency of 70 kHz. Time-reversal technique is used to further enhance the defect detection capability. A method to identify the defect is described on a finite element model. Numerical results show that the time reversal technique has the ability to evidently enhance the amplitude of damage reflected wave and improve the detection efficiency of defect.

Application of Torsional Mode of Guided Waves to Long Range Pipe Inspection

2006 ◽  
Vol 326-328 ◽  
pp. 473-476
Author(s):  
Ik Keun Park ◽  
Yong Kwon Kim ◽  
Won Joon Song ◽  
Yong Sang Cho
Keyword(s):  
Long Range ◽  
Wall Thickness ◽  
Guided Waves ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Thickness Reduction ◽  
Torsional Mode ◽  
Pipeline Inspection ◽  
Cross Section Area ◽  
Section Area

Conventional non-destructive techniques for inspection of weld in pipelines require significant test time and high cost. In order to overcome these drawbacks in conventional NDT techniques, various techniques using ultrasonic guided waves have been developed and applied to the pipeline inspection. Recently, a fast calculation technique for guided wave propagation using a semi-analytical finite element method (SAFEM), PIPE WAVE ver.1.0, has been developed by T. Takahiro et al [1]. In this paper, the calculation of torsional mode propagation in a pipe using PIPE WAVE ver. 1.0 is introduced as a preliminary study and the application of the torsional mode of ultrasonic guided waves to long range pipe inspection is presented.. The characteristics and setup of a long range guided wave inspection system and experimental results in pipes of various diameters are introduced. The experimental results in mock-up pipes with cluster type detects show that the limit of detectable wall thickness reduction with this guided wave system is 2~3% in the pipe cross section area and the wall thickness reduction of 5% in cross section area can be detected when actual detection level is used. Therefore, the applicability of the ultrasonic guided wave technique to long range pipeline inspection for wall thickness reduction is verified.

Research on the Nondestructive Detection of Ultrasonic Guided Wave Based on the Time Reversal Method

2013 ◽  
Vol 330 ◽  
pp. 996-1002
Author(s):  
Wen Chao Lv ◽  
Shao Ping Zhou ◽  
Ai Qiang Cui
Keyword(s):  
Time Reversal ◽  
Guided Waves ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Wave Method ◽  
Defect Identification ◽  
Ultrasonic Guided Wave ◽  
Wave Technique ◽  
Defects Identification ◽  
Initial Results

Because there are many mode transformations when the ultrasonic guided waves run into defects in the pipeline, the reflected signals got by means of the traditional ultrasonic guided wave technique are complex and the amplitudes are small. The time reversal method is a way to intercept the reflected signals in the initial results with a certain bandwidth and excite the time reversal guided waves on the corresponding nodes. In this way, energies of the guided wave are focused in time and space. By comparing the accuracy of defects identification in the straight pipes and the bent pipes with the traditional ultrasonic guided wave method and the time reversal method, this paper proves that the time reversal method has many advantages over the tradition ultrasonic guided wave method. The time reversal method overcomes disadvantages of the traditional guided wave technique and improves the identification degree and accuracy of defects effectively. It lays the foundation for the final defect identification.

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