Air coupling Lamb wave nonlinear ultrasonic stress detection method, system and device for fiber reinforced composite material

A nonlinear ultrasonic and composite material technology, applied in the field of air-coupled Lamb wave nonlinear ultrasonic stress detection, can solve the problems of material structure and performance damage, system error, etc., achieve fast detection speed, eliminate the influence of couplant, and test process simple effect

Pending Publication Date: 2022-02-18
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The invention solves the problem of systematic error in traditional nonlinear ultrasonic stress dete...

Method used

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  • Air coupling Lamb wave nonlinear ultrasonic stress detection method, system and device for fiber reinforced composite material
  • Air coupling Lamb wave nonlinear ultrasonic stress detection method, system and device for fiber reinforced composite material
  • Air coupling Lamb wave nonlinear ultrasonic stress detection method, system and device for fiber reinforced composite material

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Experimental program
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Embodiment 1

[0058] Embodiment 1. An air-coupled Lamb wave nonlinear ultrasonic stress detection method for fiber-reinforced composite materials described in Embodiment 1, including:

[0059] Obtain the pure Lamb wave mode according to processing the fiber-reinforced composite material to be tested, and the pure Lamb wave contains the symmetric mode S 0 and the antisymmetric mode A 0 ;

[0060] Determining the antisymmetric mode A from the dispersion curve 0 The group velocity, according to the antisymmetric A 0 Mode for air-coupled ultrasonic testing;

[0061] The fiber-reinforced composite material to be tested is detected by air-coupled ultrasonic testing, and the relative nonlinear coefficient of the fiber-reinforced composite material sample to be tested is obtained, that is, the stress characterization is achieved by obtaining the fiber-reinforced composite material sample to be tested.

[0062] In this embodiment, when the in-plane displacement of the symmetric mode is relativel...

Embodiment 2

[0063] Embodiment two, see figure 1 This embodiment will be described. This embodiment is a further limitation of the air-coupled Lamb wave nonlinear ultrasonic stress detection method for fiber-reinforced composite materials described in Embodiment 1. The pure Lamb wave mode is obtained according to the processing of the fiber-reinforced composite material to be tested. ,include:

[0064] The dispersion curve of the Lamb wave is drawn by using the parameters of the fiber reinforced composite material to be measured, and the center frequency f of the air-coupled transducer is determined in combination with the thickness of the fiber reinforced composite material to be measured.

[0065] Lamb waves have symmetric modes, antisymmetric modes and dispersion characteristics, and may excite multi-order symmetric modes (S 0 , S 1 ,...,S i ) and the antisymmetric mode (A 0 , A 1 ,...,A i ). In this embodiment, in order to allow the air-coupled transducer to excite a relatively...

Embodiment 3

[0066] Embodiment three, refer to figure 2 This embodiment will be described. This embodiment is a further limitation of the air-coupled Lamb wave nonlinear ultrasonic stress detection method for fiber-reinforced composite materials described in Embodiment 1. The antisymmetric mode A is determined according to the dispersion curve 0 The group velocity, according to the antisymmetric mode A 0 For air-coupled ultrasonic testing, the testing process system includes:

[0067] Determine A from the dispersion curve 0 Modal group velocity, using Snell's law and air speed of sound to determine the inclination angle of the exciting and receiving air-coupled transducers;

[0068] On any side of the sample in the stress concentration area, place the air-coupled transducer according to the inclination angle, and determine the distance between the air-coupled transducer and the sample according to the actual testing environment;

[0069] Determine the period N of the excitation signal...

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Abstract

The invention discloses an air coupling Lamb wave nonlinear ultrasonic stress detection method, system and device for a fiber reinforced composite material, and belongs to the field of ultrasonic stress detection. Traditional nonlinear ultrasonic stress detection has system errors, and special fiber material stress detection causes damage to the structure and performance of a material. The air coupling Lamb wave nonlinear ultrasonic stress detection method comprises: obtaining a pure Lamb wave mode by processing a to-be-detected fiber reinforced composite material, and the pure Lamb wave comprising a symmetric mode S0 and an antisymmetric mode A0; determining an antisymmetric mode A0 group velocity according to the frequency dispersion curve, and carrying out air coupling ultrasonic detection according to the antisymmetric mode A0; performing air coupling ultrasonic detection on the to-be-detected fiber reinforced composite material to obtain a relative nonlinear coefficient of the to-be-detected fiber reinforced composite material sample, namely obtaining the to-be-detected fiber reinforced composite material sample to realize stress characterization. According to the invention, the influence of a coupling agent is eliminated, the flexibility of stress detection of the fiber reinforced composite material is enhanced, and the detection efficiency is improved.

Description

technical field [0001] The invention belongs to the field of ultrasonic stress detection, in particular to an air-coupled Lamb wave nonlinear ultrasonic stress detection method for fiber reinforced composite materials. Background technique [0002] Fiber-reinforced composite materials also inherit some of the advantages of carbon fiber materials and matrix materials, and have the characteristics of low density, high strength, high modulus, wear resistance, high temperature resistance, strong antimagnetic, strong corrosion resistance, and fatigue resistance. In the past 20 years, fiber-reinforced composite materials have developed rapidly. After playing an important role in high-tech fields such as aerospace, fiber-reinforced composite materials have also gradually emerged in the fields of automobile processing, shipbuilding, and medical and chemical industries. In fiber-reinforced composite laminates, the resin material between layers is the main medium for stress transmissi...

Claims

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Application Information

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IPC IPC(8): G01L1/25
CPCG01L1/255
Inventor 赵勃史维佳王丙泉谭久彬
Owner HARBIN INST OF TECH
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