Structural microcrack vibration sound modulation detection system and structural microcrack vibration sound modulation detection method based on nonlinear vibrator

A vibration-acoustic modulation and detection system technology, which is applied to the analysis of solids using sound waves/ultrasonic waves/infrasonic waves, etc., can solve problems such as inability to choose freely, affect detection results, and dependence on low-frequency resonance frequencies, and achieve high-efficiency detection and strong anti-interference , universal effect

Inactive Publication Date: 2015-04-08
UNIV OF SCI & TECH OF CHINA
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Problems solved by technology

However, there is an obvious problem in these two types of approaches, that is, the low-frequency resonance frequency depends on the natural vibration mode of the structure and cannot be freely selected
In order to ensure a good vibration-acoustic modulat

Method used

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  • Structural microcrack vibration sound modulation detection system and structural microcrack vibration sound modulation detection method based on nonlinear vibrator
  • Structural microcrack vibration sound modulation detection system and structural microcrack vibration sound modulation detection method based on nonlinear vibrator
  • Structural microcrack vibration sound modulation detection system and structural microcrack vibration sound modulation detection method based on nonlinear vibrator

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Experimental program
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Embodiment 1

[0043] The nonlinear oscillator system described in this embodiment is as figure 2 As shown, it includes low-frequency vibration source 2-1, piezoelectric ceramic sheets 2-2 and 2-4, structure with cracks 2-3, permanent magnets 2-5 and 2-6, and base 2-7. in,

[0044] The low-frequency vibration source is low-frequency simple harmonic vibration simulated by a vibration table.

[0045] The material of the structure with cracks is phosphor copper, and the dimensions are 148mm×40mm×0.6mm (length×width×thickness), respectively, and a fatigue crack with a length of 5.8mm is produced by the fatigue test method.

[0046] The magnet system is composed of a permanent magnet 2-6;

[0047] The permanent magnet adopts NdFeB permanent magnet, the shape of the magnet is rectangular, the size is 5mm×5mm×2mm, and the magnet strength is 0.35 Tesla.

[0048] The polarities of the permanent magnets 2-5 and 2-6 are opposite in the y direction, and by adjusting the base 2-7, the right surface o...

Embodiment 2

[0056] The nonlinear oscillator system described in this embodiment is as Figure 4 As shown, it includes a low-frequency vibration source 3-1, piezoelectric ceramic sheets 3-2 and 3-4, a structure with cracks 3-3, permanent magnets 3-5, 3-6 and 3-8, and a base 3-7. in,

[0057] The low-frequency vibration source is low-frequency simple harmonic vibration simulated by a vibration table.

[0058] The material of the structure with cracks is phosphor copper, and the dimensions are 153mm×40mm×0.6mm (length×width×thickness), respectively, and fatigue cracks with a length of 6mm are produced by the fatigue test method.

[0059] Described magnet system is made of two identical permanent magnets 3-6 and 3-8, and two magnets are placed in parallel along the x direction, and the distance between magnet centers is p, which is set to 6.2mm in this embodiment;

[0060] The permanent magnet adopts NdFeB permanent magnet, the shape of the magnet is rectangular, the size is 5mm×5mm×2mm, an...

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Abstract

The invention discloses a structural microcrack vibration sound modulation detection system and a structural microcrack vibration sound modulation detection method based on a nonlinear vibrator. The structural microcrack vibration sound modulation detection system comprises a signal generator (1), a low-frequency vibration source (2), a first piezoelectric ceramic wafer (3), a second piezoelectric ceramic wafer (4), a structure (5) with cracks, a permanent magnet (6), a magnet system (7), a signal recording analyzer (8) and a power amplifier (9). The structure with microcracks is used as a cantilever beam to form nonlinear vibrator system, the limitation of a linear vibrator can be overcome by utilizing the nonlinear vibrator, and obvious vibration sound modulation effect in a wide frequency band range can be realized. The system and the method have the technical advantages that the vibration sound modulation detection of the microcrack can be carried out at the non-resonant frequency, so that the high-efficiency detection can be carried out by utilizing the optional ambient vibration. In addition, the system and the method also have the advantages of simple principle, strong interference resistance, high universality and the like.

Description

technical field [0001] The invention relates to the technical field of non-destructive testing, in particular to a vibration-acoustic modulation detection system and method for structural micro-cracks based on nonlinear oscillators. Background technique [0002] During the service process of engineering structures, microcracks are often generated due to fatigue. These microcracks are the early manifestations of defects in structural materials. Under certain external factors, microcracks continue to expand and merge, and finally form macrocracks. Therefore, microcrack defects are a major safety hazard for mechanical equipment and engineering structures. Diagnosing internal microcrack defects in the initial damage stage of materials is of great significance for timely predicting structural material damage and ensuring healthy service of structures. [0003] Among the current structural damage detection methods, ultrasonic testing, as a non-destructive testing technology, has...

Claims

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Application Information

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IPC IPC(8): G01N29/04
Inventor 何清波许艳艳潘媛媛
Owner UNIV OF SCI & TECH OF CHINA
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