Time reversal focusing method-based method for judging size of pipeline defect
A technology of time-reversal focusing and defects, which is applied to the analysis of solids using sound waves/ultrasonic waves/infrasonic waves, and can solve problems such as the inability to determine the size of defects
Active Publication Date: 2013-10-23
BEIJING UNIV OF TECH
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[0004] The purpose of the present invention is to solve the current situation that the defect size cannot be determined in the current ultrasonic guided wave pipeline inspection
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[0021] Provide following test embodiment in conjunction with the content of the inventive method:
[0022] (1) Utilize the time-reversal ultrasonic guided wave pipeline detector (see patent ZL200610144294), a steel seamless steel pipe with a length of 2 meters and an outer diameter of 144 millimeters and a wall thickness of 5 millimeters is detected, and the obtained results are as follows: figure 1 Routine assay curves are shown.
[0023] (2) Use the time-reversal ultrasonic guided wave pipeline detector to perform time-reversal focusing detection on the defects on the pipeline in step (1), and obtain the following: figure 2 Post-focus detection curves are shown.
[0024] (3) Using the pre-focus detection curve described in step (1), the time t of the defect echo signal = 4.9 × 10 -4 seconds and the corresponding wave velocity of ultrasonic guided wave in the pipeline c=5.8×10 3 m / s to calculate the defect position
[0025] (4) Extract the amplitude A of the defect ech...
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The invention provides a time reversal focusing method-based method for judging the size of a pipeline defect, belonging to the field of nondestructive testing signal analysis. The time reversal focusing method-based method comprises the following steps of: calculating a defect position by virtue of a detection curve before focusing and extracting an amplitude A1 of a defect echo-wave signal, and calculating an amplitude A2 of the defect echo-wave signal by virtue of the detection curve after focusing; calculating an amplification factor; in finite element software, establishing a series of definite element pipeline models which are in accordance with material, length, outer diameter and wall thickness parameter of a detected pipeline and are provided with different size defects; acquiring amplification factors of defects in different circumference directions by adopting the time reversal focusing method; drawing a size change curve of the amplification factors along with the defect circumference direction, and finding out a point corresponding to the amplification factor R, wherein the size of the defect circumference direction of the point corresponding to an amplification factor change curve chart along with the defect circumference direction is the size of the defect circumference direction to be detected. According to the method, the size of circumference direction of the pipeline can be judged, and the defect position and the defect circumference direction size can be calculated by once detection.
Description
technical field [0001] The invention relates to a guided wave signal analysis method based on time delay, and belongs to the field of nondestructive detection signal analysis. Background technique [0002] Ultrasonic guided wave detection of defects and damages in pipelines is a new pipeline detection technology that has emerged in recent years. Compared with conventional magnetic flux leakage, eddy current, and ray methods, it has the advantages of high detection efficiency, long propagation distance, large detection range, no need to peel off the outer cladding, no need to fully excavate buried pipelines, and online detection. General pipeline detection, for elevated pipelines, clad pipelines, buried pipelines, pipelines passing through road subgrade sections and wall sections, pipelines running in water, etc. Compared with traditional ultrasonic testing, ultrasonic guided wave technology has the advantages of long detection distance (up to 200 meters), 100% detection of ...
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IPC IPC(8): G01N29/04
Inventor 吴斌符浩何存富周进节
Owner BEIJING UNIV OF TECH