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A method for detecting crack types in brittle materials based on acoustic emission

A technology of brittle material and detection method, which is applied in the direction of material analysis, material analysis, and detection response signal processing using acoustic wave emission technology, which can solve the problem of inability to judge the normal and movement direction of the crack surface.

Active Publication Date: 2022-07-12
CHINA JILIANG UNIV
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  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to overcome the deficiency that the RA-AF analysis method distinguishes the crack type depending on the coordinate ratio between the two parameters, and cannot judge the normal line and motion direction of the crack surface, and proposes a crack type of brittle material based on acoustic emission Detection method

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  • A method for detecting crack types in brittle materials based on acoustic emission
  • A method for detecting crack types in brittle materials based on acoustic emission
  • A method for detecting crack types in brittle materials based on acoustic emission

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Embodiment 1

[0033] In this embodiment, the brittle material to be monitored is concrete, and the Brazilian disc splitting test is performed on the concrete. The size of the concrete disc specimen is Φ106mm×54mm.

[0034] The concrete material crack type is detected by using the acoustic emission-based brittle material crack type detection method proposed by the present invention, and the specific operation steps are as follows:

[0035] Step 1. 8 acoustic emission sensors are symmetrically arranged on the front and rear surfaces of the concrete disc specimen, and their coordinates are (-a, a, b), (a, a, b), (a, -a, b), (-a,-a,b), (-a,a,-b), (a,a,-b), (a,-a,-b), (-a,-a,-b), Among them, a=21.21mm, b=27mm, specifically as figure 1 shown. figure 1 The numbers 1 to 8 in the above represent the serial numbers of the 8 acoustic emission sensors, respectively.

[0036] Step 2: For the first acoustic emission event, select the acoustic emission signals received by the 6 sensors No. 8, 3, 5, 4, ...

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Abstract

The invention relates to a method for detecting crack types of brittle materials based on acoustic emission, and belongs to the technical field of material damage detection. The steps are: arranging an acoustic emission sensor on the brittle material to be monitored, and collecting the acoustic emission signal; performing wavelet noise reduction processing on the acoustic emission signal, and extracting the initial motion amplitude of the acoustic emission signal; according to the position of the acoustic emission source and the arrangement position of the sensor, Establish a moment tensor equation system; solve the moment tensor, calculate the eigenvalues ​​of the moment tensor, and calculate the eigenvectors corresponding to the eigenvalues ​​of the moment tensor; calculate the angle between the normal direction vector and the motion direction vector of the crack surface; The angle between the normal direction vector and the motion direction vector of the crack surface and the waveform and frequency characteristics of the acoustic emission signal are used to determine the crack type of the brittle material to be monitored. The method proposed by the invention overcomes the shortcomings of the RA-AF analysis method, can quantitatively obtain the normal direction and the movement direction of the micro-crack surface, and realizes the detection of the crack type of the brittle material.

Description

technical field [0001] The invention belongs to the technical field of material damage detection, and relates to a method for detecting crack types of brittle materials based on acoustic emission. Background technique [0002] Under the action of external loads, the internal micro-defects of engineering materials will continue to expand and evolve, eventually leading to failure of materials or structures. How to detect or identify these micro-defects and evaluate the damage degree and development trend of the structure is an important problem in the engineering field. The formation and propagation of microcracks in brittle materials is an irreversible energy dissipation process, which releases the surface energy of microcracks in the form of transient elastic waves, a phenomenon called acoustic emission. Acoustic emission technology, as a physical detection method, can obtain the physical information of the change of the internal mesostructure of the material in real time. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N29/14G01N29/12G01N29/44
CPCG01N29/14G01N29/12G01N29/44G01N2291/106Y02P40/57
Inventor 王宗炼王怀伟胡剑虹梁明轩
Owner CHINA JILIANG UNIV