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Metal plate stress detection method based on electromagnetic ultrasonic Lamb wave S1 modal group velocity

An electromagnetic ultrasonic and stress detection technology, which is applied in the analysis of solids using sonic/ultrasonic/infrasonic waves, material analysis using sonic/ultrasonic/infrasonic waves, and measuring devices, etc. It can solve the problem of low Lamb wave velocity test accuracy and difficult extraction of waveform modes. and separation, complex Lamb wave signals, etc., to achieve the effect of increasing the rate of change of velocity, obvious amplitude, and easy use.

Active Publication Date: 2021-02-05
HEBEI UNIV OF TECH
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Problems solved by technology

[0006] In summary, for the research on the stress of metal sheets, due to the multi-modality and dispersion of Lamb waves, the Lamb wave signals are complex, the waveform modes are not easy to extract and separate, and the accuracy of Lamb wave velocity testing is low. The method of detecting the stress distribution of the metal plate by the variation of the Lamb wave group velocity has not been proposed

Method used

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  • Metal plate stress detection method based on electromagnetic ultrasonic Lamb wave S1 modal group velocity
  • Metal plate stress detection method based on electromagnetic ultrasonic Lamb wave S1 modal group velocity
  • Metal plate stress detection method based on electromagnetic ultrasonic Lamb wave S1 modal group velocity

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Embodiment 1

[0059] In this embodiment, a 6061-style aluminum plate with a thickness of 1 mm is used, and its size is 600 mm in length and 60 mm in width.

[0060] (1) Adopt MATLAB simulation to calculate the dispersion curve of each mode of the Lamb wave in the aluminum plate under different stresses; Described each mode comprises basic mode S0 and A0 and first-order mode A1 and S1;

[0061] (2) According to the propagation characteristics of the fundamental mode and the first-order mode of the Lamb wave, respectively select the cut-off frequency of the cut-off stage in the dispersion curve of the S0, A0, A1 and S1 modes of the Lamb wave (that is, the frequency of the maximum change in velocity ),according to image 3 It can be seen that the cut-off frequency of the S1 mode is 3MHz, the S0 mode is 1MHz, the A0 mode is 2MHz, and the A1 mode is 2.2MHz; the frequency-thickness product of each mode is calculated; the frequency-thickness product is 3MHz. mm, the S1 mode group has the slowest ...

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Abstract

The invention discloses a metal plate stress detection method based on electromagnetic ultrasonic Lamb wave S1 modal group velocity. According to the method, an electromagnetic ultrasonic excitation probe is adopted to excite Lamb waves, Lamb waves in a specific mode are excited according to specific intervals of excitation coils, the S1 mode of the Lamb waves is accurately recognized, and stressdetection is conducted on a metal plate through high sensitivity of the S1 mode group speed of the Lamb waves to stress changes. Compared with traditional body wave stress detection, the method has the advantages that the speed change rate is remarkably increased under the same loading stress, and the method can be used for measurement and research of sheet stress distribution in the field of nondestructive testing.

Description

technical field [0001] The invention belongs to the field of electromagnetic ultrasonic detection, in particular to a metal plate stress detection method based on electromagnetic ultrasonic Lamb wave S1 modal group velocity. Background technique [0002] Plate structure materials are raw materials for basic industries, and play an important role in industrial and civil equipment due to their advantages of light weight, high strength, high modulus, and long life. The existence of residual stress will not only reduce the static strength and fatigue strength of the workpiece, causing process defects such as deformation cracking during manufacture and use, but also affect the corrosion resistance of the material during the natural release process after manufacture. Therefore, research and detection of residual stress in plate structure materials are of great significance to production and scientific experiments. [0003] Non-destructive testing can use X-ray, neutron diffractio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N29/04G01N29/07
CPCG01N29/041G01N29/07G01N2291/011G01N2291/0234G01N2291/02827G01N2291/0427G01N2291/2632
Inventor 张闯于海旭刘素贞金亮郭玉凤
Owner HEBEI UNIV OF TECH
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