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Method for non-contact wave velocity extraction of Rayleigh wave of anisotropic blocky material

A kind of wave speed extraction, non-contact technology, applied in the direction of response signal detection, etc., to avoid random errors

Active Publication Date: 2013-11-06
BEIJING UNIV OF TECH
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  • Summary
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to solve the problem of extracting the Rayleigh wave broadband continuous wave velocity of isotropic bulk materials, and propose an advanced material wave velocity extraction method

Method used

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  • Method for non-contact wave velocity extraction of Rayleigh wave of anisotropic blocky material
  • Method for non-contact wave velocity extraction of Rayleigh wave of anisotropic blocky material
  • Method for non-contact wave velocity extraction of Rayleigh wave of anisotropic blocky material

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Embodiment Construction

[0039] Below in conjunction with specific example, content of the present invention is described in further detail:

[0040] Step 1): Establish the formula for wave velocity extraction.

[0041] In the case of single frequency excitation / reception, figure 2 In the schematic diagram of the propagation of the leaky surface wave shown, the propagation time of the direct reflection echo I on the upper surface and the propagation time of the leaky surface wave L are respectively:

[0042] t 1 = 2 ( R - Vz ) v w - - - ( 1 )

[0043] t 2 = 2 ( R ...

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Abstract

The invention discloses a method for the non-contact wave velocity extraction of a Rayleigh wave of an anisotropic blocky material, and the method belongs to the technical field of nondestructive examination. In the nondestructive examination for mainly measuring the wave velocity of an acoustic wave, a V(z) curve formed by the interference of a leaky surface wave and a directly reflected wave, namely a longitudinal wave, comprises much information at the microstructure aspect of the material; the method is based on a defocusing measurement system; a wide-frequency pulse is utilized as an excitation source; an ultrasonic wave comprising a plurality of frequency components is received; and the V(z) curve of the material and an oscillating period thereof are obtained through an improved two-dimensional Fourier transform technique, so as to achieve the extraction of the wave velocity of the Lamb wave of the blocky material. By using the method, the wave velocities of the Rayleigh waves of different materials can be extracted; the wave velocity of the Rayleigh wave can be extracted in a wide frequency scope; a single-frequency point-by-point way is replaced; the wave velocities of the Rayleigh waves in different frequency ranges can be extracted; an averaged value is selected as the wave velocity of the Rayleigh wave of the material; and the random error caused by an accidental factor in a single-frequency extraction process is avoided.

Description

technical field [0001] The invention belongs to the field of non-destructive testing, and in particular relates to a wave velocity extraction method for Rayleigh waves of isotropic block materials. Background technique [0002] With the continuous development of material science, various functional materials are emerging, but affected by the preparation process, the geometric size of many new materials is very limited, such as metallic glass, bulk nanomaterials, etc. Therefore, the method of testing destructive traditional mechanical properties such as tensile will not be able to meet the needs of new materials. In the non-destructive testing mainly measuring the acoustic wave velocity, the V(z) curve formed by the interference of the leakage surface wave and the direct reflection wave contains a lot of information on the microstructure of the material. Using an ultrasonic microscope as a wave velocity measurement tool, it can Applied to the detection of mechanical properti...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N29/36
Inventor 何存富吕炎宋国荣柳艳丽高忠阳吴斌
Owner BEIJING UNIV OF TECH