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Improved Lamb wave engineering structure crack damage monitoring and estimating tomographic imaging method

A tomography and damage monitoring technology, which is applied to the analysis of solids using sonic/ultrasonic/infrasonic waves, and can solve the problems of the direction and length of cracks, which are difficult to assess and reconstruct crack damage.

Inactive Publication Date: 2015-04-08
NANJING UNIV OF POSTS & TELECOMM
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Problems solved by technology

However, due to the complexity of Lamb wave propagation, there is an endpoint effect when a crack is encountered, and the conversion of the Lamb wave mode will occur at the end of the crack, which brings difficulties to the evaluation of the direction and length of the crack and the reconstruction of the crack damage.

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  • Improved Lamb wave engineering structure crack damage monitoring and estimating tomographic imaging method
  • Improved Lamb wave engineering structure crack damage monitoring and estimating tomographic imaging method
  • Improved Lamb wave engineering structure crack damage monitoring and estimating tomographic imaging method

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Embodiment Construction

[0033] The technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings.

[0034] The invention provides an improved Lamb wave engineering structure crack damage monitoring and evaluation tomography method, the basic principle of which is: due to the dispersion effect, during the propagation process of Lamb wave mode signals, different frequency components propagate at different propagation speeds, It causes the continuation and aliasing of the signal wave packet, and the damage scattering signal is often relatively weak, and it is easy to be lost in these waveforms during the aliasing process with the direct wave signal and the boundary reflection signal. In traditional Lamb wave tomography technology, wave velocity or energy attenuation is usually selected as the characteristic parameters of damage detection and image reconstruction. In order to reconstruct the damage image accurately, it not only needs to arran...

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Abstract

The invention discloses an improved Lamb wave engineering structure crack damage monitoring and estimating tomographic imaging method. The method comprises the steps of arranging an excitation / sensing circular array on a to-be-detected structure, establishing a detection passage, acquiring Lamb wave response signals of all excitation / sensing passages, and calculating an SDC value of each excitation / sensing passage; grouping the Lamb wave response signals, selecting a maximum SDC value in each group, and determining the direction of a crack according to two minimum values in all maximum SDC values; correcting the SDC value in the direction of the crack, and reconfiguring a damage image of the crack by adopting an RAPID algorithm; drawing an SDC distribution diagram of a receiving end, damaging a sensing route with the SDC value being greater than a set threshold value, and calculating the length of the crack according to a mathematic geometric relation. By adopting the method, the influence on the signal analysis caused by complicated multi-mode propagation characteristics of the Lamb wave can be overcome, the image reconfiguration of the crack damage is realized by utilizing the improved RAPID algorithm to correct the SDC value in the direction of the crack, and the length of the crack is evaluated by virtue of the SDC distribution diagram on the receiving end.

Description

technical field [0001] The invention belongs to the technical field of tomography, and in particular relates to an improved tomographic imaging method for monitoring and evaluating crack damage of Lamb wave engineering structures. Background technique [0002] With the continuous improvement of structural safety and reliability requirements, the detection and diagnosis of structural damage has attracted increasing attention, especially for the detection of crack damage. In order to prevent disasters or losses caused by structural damage, it is necessary to Effective rapid detection. [0003] Lamb wave is an elastic guided wave propagating in a solid structure under free boundary conditions. It has slow attenuation, long propagation distance, and is very sensitive to small damage in the structure. The aerospace field has expanded to the fields of civil engineering, ships, railways and automation industries, and plays an important role in ensuring structural safety and reduci...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N29/11G01N29/06
Inventor 王强胥静
Owner NANJING UNIV OF POSTS & TELECOMM
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