Method of frequency-doubling modulation nonlinear ultrasonic guided wave time-reversal detection of pipeline microcracks

A nonlinear ultrasonic and time-reversal technology, applied in the generation of ultrasonic/sonic/infrasonic waves, the analysis of solids using sonic/ultrasonic/infrasonic waves, and the material analysis using sonic/ultrasonic/infrasonic waves, which can solve the problem of poor detection effect and safety. hidden dangers, production accidents and other problems, to achieve the effect of high sensitivity

Active Publication Date: 2021-01-01
山东省特种设备检验研究院集团有限公司
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Problems solved by technology

When the area and density of micro-cracks gradually increase, macro-cracks will be formed, causing structural failure and potential safety hazards, and serious cases will lead to production accidents
[0003] Ultrasonic non-destructive testing is a widely used crack detection method. The existing linear ultrasonic testing method is based on sound velocity and acoustic impedance to detect cracks. The size of the microcrack is generally much smaller than the wavelength of the linear detection ultrasound, and the local material property change caused by the microcrack is very small, and the detection effect of the microcrack by linear ultrasound is very poor.

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  • Method of frequency-doubling modulation nonlinear ultrasonic guided wave time-reversal detection of pipeline microcracks
  • Method of frequency-doubling modulation nonlinear ultrasonic guided wave time-reversal detection of pipeline microcracks
  • Method of frequency-doubling modulation nonlinear ultrasonic guided wave time-reversal detection of pipeline microcracks

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Embodiment Construction

[0049] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0050] A method for detecting pipeline microcracks by frequency-multiplying modulated nonlinear ultrasonic guided wave time-reversal, comprising the following steps:

[0051] Step 1. Signal excitation: Two excitation ultrasonic transducer groups, the first group is single low frequency, the excitation frequency is 32kHz, and a single piezoelectric chip is glued to the side of the pipeline, which is group A; the second group is arranged in The piezoelectric ultrasonic transducer array distributed at equal intervals around the pipeline can control and excite the double high-frequency torsional mode T(0,1) mode, and the excitation frequency is 64kHz, which is group B;

[0052] According to the nonlinear characteristics, the output displacement for an input mixed frequency signal is:

[0053] u (0) (x,t)=Acos(ω 1 t)+Bcos(ω 2 t) (1)

[0054] ω ...

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Abstract

The invention discloses a method for detecting pipeline microcracks by frequency multiplication modulation nonlinear ultrasonic guided wave time reversal, which belongs to the field of non-destructive testing. The steps are as follows: 1) Signal excitation: two sets of transmitting ultrasonic transducers, the first set excites single low frequency; the second set excites double high frequency; 3) nonlinear analysis: according to the sound field modulation side lobe frequency is ω 1 +ω 2 =3ω 1 Signal selection time reversal window function; 4) Signal time reversal: reverse the intercepted time reversal signal, and then send the time reversal signal by the excitation signal transducer; 5) Energy focusing: the signal is realized at the microcrack focus. The invention utilizes the advantages of long propagation distance of ultrasonic guided wave and high sensitivity of nonlinear ultrasound to microcracks, and at the same time utilizes the characteristics of time reversal algorithm self-adaptive focusing to realize identification of microcracks; uses nonlinear ultrasonic parameters to discriminate the size of cracks.

Description

technical field [0001] The invention belongs to the field of non-destructive testing, and relates to a method for detecting pipeline microcracks by frequency-multiplying modulated nonlinear ultrasonic guided wave time-reversal. Background technique [0002] After the material is subjected to high temperature, high pressure and long-term cyclic load, micro-cracks and micro-damages of different degrees will appear in the stress concentration area. When the area and density of micro-cracks gradually increase, macro-cracks will be formed, resulting in structural failure, potential safety hazards, and serious production accidents. [0003] Ultrasonic non-destructive testing is a widely used crack detection method. The existing linear ultrasonic testing method is based on sound velocity and acoustic impedance to detect cracks. The size of the microcrack is generally much smaller than the wavelength of the linear detection ultrasound, and the local material property change caused ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N29/04G01N29/34
CPCG01N29/04G01N29/343G01N29/348G01N2291/0289
Inventor 谷涛张峰左晓杰席光峰张皓张维刘爽
Owner 山东省特种设备检验研究院集团有限公司
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