Sheet metal micro-crack time reversal positioning method based on abaqus

A technology of time reversal and positioning method, which is applied in the direction of processing detection response signals, etc., can solve the problems of ignoring dispersion characteristics and inaccurate calculation results, and achieve the effect of convenient operation, time saving and low cost

Inactive Publication Date: 2016-02-24
CHINA JILIANG UNIV
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Problems solved by technology

This method ignores the dispersion characteristics of ultrasonic waves propagating in thin plates, and the calculation results are not accurate

Method used

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  • Sheet metal micro-crack time reversal positioning method based on abaqus
  • Sheet metal micro-crack time reversal positioning method based on abaqus
  • Sheet metal micro-crack time reversal positioning method based on abaqus

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example

[0022] Dynamic sound modulation detection system such as figure 1 As shown, it mainly includes: a thin aluminum plate with a length of 400mm, a width of 200mm, and a thickness of 2mm, with a Young’s modulus of 72GPa and a Poisson’s ratio of 0.35. There is a closed crack at the center of the plate with a length of 10mm and a width of nano-micro; the diameter is 25mm, Thickness stretchable piezoelectric ceramic sheet with a thickness of 2mm and a center frequency of 40kHz; signal generator (DG1022U); oscilloscope (DS2102); power amplifier (JYH-200M), etc.

[0023] Because when the frequency of the vibration signal is selected as the modal frequency of the specimen, the phenomenon of vibration-acoustic modulation is most obvious. Therefore, first perform a modal test on the specimen, select the frequency sweep mode in the signal generator, set the start frequency to 1000Hz, the end frequency to 6000Hz, the amplitude to 100V, and the sampling frequency to 1MHz. The signal is inpu...

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Abstract

The invention relates to a sheet metal micro-crack time reversal positioning method based on abaqus. The invention adopts a method combining test and numerical simulation to solve the technical problem. First, a scattering signal corresponding to damage is obtained through the experiment, and time reversal is calculated; and then re-excitation is carried out on an abaqus finite element model simulating an actual sheet, so as to obtain spatial distribution of time reversal sound field, and realize damage localization and imaging. Compared to a traditional method, which directly conducts time reversal excitation on the specimen and then scans the whole sheet through a vibration measurement with laser to determine the focus location of the signal, the invention uses the finite element simulation software to simulate the time reversal focusing process, and has the advantages of lower cost, and convenient and time-saving operation.

Description

technical field [0001] The invention relates to an abaqus-based time-reversal positioning method for micro-cracks in thin metal plates. Background technique [0002] The conventional ultrasonic testing method is based on the linear characteristics of the reflection, attenuation, and transmission of the propagation signal. However, due to the low reflection echo intensity, high transmittance, and small attenuation of micro-cracks, the conventional ultrasonic testing method is not sensitive to micro-cracks. . Researchers at home and abroad have found that the nonlinear behavior caused by internal fatigue damage of materials can be well reflected by nonlinear ultrasonic testing methods. Nonlinear ultrasonic testing is to use the nonlinear response signal generated by the interaction of medium or small defects when ultrasonic waves propagate in materials, to evaluate material properties and detect small defects. Vibroacoustic modulation is one of the non-linear ultrasonic test...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N29/44
CPCG01N29/44
Inventor 郑慧峰方漂漂王月兵曹永刚郭世旭
Owner CHINA JILIANG UNIV
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