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Damage imaging system based on Lamb waves

An imaging method, fast technology, applied in processing detection response signals, using acoustic wave emission technology for material analysis, instruments, etc., can solve problems such as inability to detect damage, and achieve the effect of rapid identification and positioning

Inactive Publication Date: 2018-07-10
海宁盛台材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, such technology can only be used as an auxiliary means of ultrasonic research, and cannot be directly applied to the damage detection of actual structures.
Generally speaking, since the amplitude of the ultrasonic wave on the surface of the structure is on the order of 10-3mm, there are many difficulties in technically completing the ultrasonic visualization of the opaque structure. At present, people can only use the expensive laser interferometer system (Laser interferometer system). complete this task

Method used

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  • Damage imaging system based on Lamb waves

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] The goal of this embodiment is to detect aluminum plates with elliptical through holes (such as Figure 8 ). Aluminum plate model such as Picture 9 As shown, the major axis of the elliptical through hole is 15mm, the minor axis is 12mm, and the thickness of the aluminum plate is 5mm. In order to simplify the experiment, the elliptical through hole is regarded as damage, although in actual situations the elliptical through hole is visible to the naked eye, it does not Damage category. Irradiating the aluminum plate with a laser pulse (8.5 ns) produces a Lamb wave, the main components of which are S0 mode and A0 mode, and the energy of the wave is mainly concentrated between 100kHz and 200kHz. In this frequency domain, the wavelength of the A0 mode is about 10mm; the wave speeds of the S0 mode and A0 mode are about 5000m / s and 3000m / s.

[0053] Use the method of the invention to detect:

[0054] Step 1. Detect the attenuation rate of Lamb wave in the aluminum plate. In an ...

Embodiment 2

[0061] The goal of this embodiment is to detect aluminum plates with unpierced cracks. Aluminum plate model such as Picture 12 As shown: the length of the crack is 20mm, the width is 2mm, and the depth is 2.5mm; the thickness of the aluminum plate is 5mm. In order to simplify the experiment, the non-penetrating crack is regarded as damage here. Select the surface where the crack is located as the laser scanning plane.

[0062] The detection steps and setting parameters are the same as in Example 1. Figure 13 Schematic diagram of the detection area.

[0063] The diagnosis result of this embodiment is as Figure 14 As shown: the red and green areas in the figure are the damage results diagnosed by the present invention, and the white ellipse represents the real damage. It can be seen that the crack damage can be accurately located, but its shape and size are about 50% different from the actual situation.

Embodiment 3

[0065] The goal of this embodiment is to detect delamination-containing carbon fiber reinforced composite laminates (such as Figure 15 Shown). The composite laminate structure used in the experiment is ((45° / 0° / -45° / 90°) 4 ] s , The plate thickness is 4.8mm. There is delamination in the middle of the composite laminate. The delamination is obtained by a low-speed impact of a 4.6kg weight by a hammer impact tester (Dynatup 9250HD). Figure 16 For the ultrasonic C-scan detection to obtain the delamination damage map: the scan surface is the impact surface and the result is Figure 16 a; the result of scanning the surface as the non-impact surface (the plane on the other side of the impact surface) is Figure 16 b.

[0066] Irradiating the carbon fiber reinforced composite material laminate with a laser pulse (8.5 ns) generates a Lamb wave, the main components of which are S0 mode and A0 mode, and the energy of the wave is mainly concentrated between 50kHz and 300kHz. In this frequ...

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Abstract

The invention discloses a rapid damage imaging method based on Lamb waves and a damage diagnosis system implementing the method. The method includes a laser illumination scheme and a signal processingalgorithm. According to the damage diagnosis system, a pulse laser device is used for generating pulsed laser beams to illuminate a flaw detection area of an object to be measured and exciting ultrasonic waves; a piezoelectric sensor is closely bonded to the surface of the object to be measured; an amplifier receives electrical signals of the piezoelectric sensor for amplification, an oscilloscope converts the electrical signals into digital signals and then inputs the digital signals into a host, the host receives the electrical signals for data processing and draws a damage diagnosis map, adisplayer displays a result, and the host is connected to the pulse laser device through an interface bus and controls the pulse laser device. The method and the system have the advantages that damage is rapidly identified and located, and damage shape and size information is provided.

Description

Technical field [0001] The invention belongs to the field of structural damage diagnosis. Aiming at large structures such as airplanes, aircrafts, high-speed trains, ships, etc. that use thin-walled structures, the Lamb wave is used to achieve rapid non-destructive detection of thin-walled structures and their damage Image diagnosis. Background technique [0002] At present, the number of various aging structures in my country’s industry is rapidly increasing. In order to make these structures operate more safely and avoid the occurrence of major economic losses and casualties, and to reduce operating costs. To ensure the safe work of the structure when it is close to or exceed the design life, the application of various non-destructive testing methods, the reliability evaluation and maintenance of various aging structures has become a major issue facing my country's production and life. [0003] Various non-destructive inspection methods that are currently widely used include: ult...

Claims

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Application Information

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IPC IPC(8): G01N29/14G01N29/48
CPCG01N29/14G01N29/48G01N2291/015G01N2291/0237G01N2291/0289G01N2291/0427
Inventor 胡宁阿拉木斯吴良科
Owner 海宁盛台材料科技有限公司
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