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Method for no-reference quantitative inspection of panel thinning defect based on Lamb wave

A flat-panel, defect-free technology that is used in processing the response signals of detection, using sonic/ultrasonic/infrasonic waves to analyze solids, instruments, etc.

Inactive Publication Date: 2016-11-23
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the traditional ultrasonic testing technology mostly uses ultrasonic transducers arranged on the surface of the structure to send and receive body waves to detect defects inside the material or near the surface adjacent to the contact surface, and the coverage is extremely limited.
For large components, a complete raster scan is often required to obtain comprehensive information, which is time-consuming and laborious
And for some unreachable areas, it is generally impossible to detect

Method used

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  • Method for no-reference quantitative inspection of panel thinning defect based on Lamb wave
  • Method for no-reference quantitative inspection of panel thinning defect based on Lamb wave
  • Method for no-reference quantitative inspection of panel thinning defect based on Lamb wave

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Experimental program
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Embodiment

[0201] 1. Carry out modal separation on the total field, and solve the reflection coefficient of the required Lamb wave mode:

[0202] figure 2 A flat plate with thinning defects is shown, w is the width of the defect surface, b is the half thickness of the plate, S - , S + , S and S′ are respectively the boundary of the non-defective plate, the lower boundary of the non-defective plate, the defect boundary of the plate and the virtual boundary of the defect surface. The defect range V is surrounded by the boundaries S and S′, d(x 1 ) is the defect expression to be sought, and the abscissa x 1 at half-thickness figure 2 Shown, the ordinate x 2 The direction is downward, and the incident wave is along the x 1 Negative direction, interacting with defects to generate reflected wave u ref and the transmitted wave u tra . According to the orthogonality of different modes of the wave field, any two modes of the Lamb wave in the plate are taken as and The cross-sectiona...

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Abstract

The invention discloses a method for no-reference quantitative inspection of panel thinning defect based on Lamb wave. The method comprises the following steps: solving a coefficient of the required Lamb wave reflection modal; solving a green function in a zero-defect panel; constructing a boundary integral equation by use of the dynamics reciprocal theory and far-field basic solution; substituting a reflection coefficient into the boundary integral equation and performing inverse Fourier transform to finally obtain a defect expression; and reconstructing the defect position and shape in the panel. In the invention, the problems of quantitative inspection of panel thinning defect are effectively solved, the panel defect is reconstructed by directly using the reflection information of Lamb wave without referring to any condition in advance, and an efficient and accurate method is provided for engineering quantitative detection.

Description

technical field [0001] The invention belongs to the technical field of non-destructive testing, and relates to a method for quantitatively detecting plate thinning defects based on Lamb waves without reference. Background technique [0002] With the development of science and technology, the requirements for defect detection and evaluation in the machinery, construction and aerospace industries are getting higher and higher. It is no longer only satisfied with the detection of defect positions and fuzzy shapes, but needs to quantitatively give the exact position and details of defects. shape. [0003] Conventional non-destructive testing and evaluation methods in the industry include magnetic particle testing, radiographic testing, eddy current testing, ultrasonic testing, etc. Among them, ultrasonic non-destructive testing is a widely used testing method. Due to the high frequency and short wavelength of ultrasound, it can interact with tiny features in the structure: such...

Claims

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Application Information

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IPC IPC(8): G01N29/04G01N29/44
CPCG01N29/04G01N29/44G01N2291/023
Inventor 王彬笪益辉钱征华
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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