Horizontal shear guided wave thickness measuring method based on electromagnetic ultrasonic transducer

A horizontal shear and electromagnetic ultrasonic technology, applied in the direction of using ultrasonic/sonic/infrasonic waves, instruments, measuring devices, etc., can solve the problems of measuring the thickness of difficult metal specimens, and achieve small sound wave attenuation, high detection efficiency, multi-mode and Simple effects with dispersion characteristics

Inactive Publication Date: 2013-10-30
HARBIN INST OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] In order to solve the problem that the existing electromagnetic ultrasonic body wave thickness measurement method is difficult to measure the thickness of metal specimens with a thickness of less than 10 mm, the present invention proposes a horizontal shear guided wave thickness measurement method based on electromagnetic ultrasonic transducers

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  • Horizontal shear guided wave thickness measuring method based on electromagnetic ultrasonic transducer
  • Horizontal shear guided wave thickness measuring method based on electromagnetic ultrasonic transducer
  • Horizontal shear guided wave thickness measuring method based on electromagnetic ultrasonic transducer

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specific Embodiment approach 1

[0018] Specific implementation mode one: the horizontal shear guided wave thickness measurement method based on the electromagnetic ultrasonic transducer described in this implementation mode is realized by the following steps:

[0019] Step 1: Calculate the excitation equation of the horizontal shear guided wave in the test piece 1:

[0020] 4 f ′ 2 c s 2 - 1 L ′ 2 = n 2 , n ∈ { 1,2,3 . . . } Formula 1

[0021] In Equation 1, the parameter c s Indicates the shear wave velocity of the test piece 1; the parameter L' indicates the ratio ...

specific Embodiment approach 2

[0030] Specific embodiment two: the difference between this embodiment and specific embodiment one is that the position coefficient γ of the SHn mode of the reference specimen calculated in step five is obtained by formula 3:

[0031] γ = ( c max - c g ) · ( c max · c g + 1 ) ( c g - c min ) · ( ...

specific Embodiment approach 3

[0032] Specific embodiment 3: The difference between this embodiment and specific embodiment 1 is that in step 6, according to the position coefficient γ described in step 5, the propagation velocity c of the horizontal shear guided wave in the SHn mode in the test piece 1 is obtained 1 The solution equation in uses Equation 4:

[0033] ( c max 1 - c 1 ) · ( c max 1 · c 1 + 1 ) ( c 1...

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Abstract

A horizontal shear guided wave thickness measuring method based on an electromagnetic ultrasonic transducer solves the problem that the existing electromagnetic ultrasonic body wave thickness measuring method can not measure thickness of metal test pieces with the thickness less than 10mm. The method comprises 1 calculating an excitation equation of horizontal shear guided waves; 2 drawing an excitation curve; 3 calculating and solving a group velocity equation of the horizontal shear guided waves; 4 exciting and receiving the horizontal shear guided waves in a reference test piece with known thickness and drawing a velocity-thickness corresponding relation curve; 5 measuring the maximum velocity and the minimum velocity of the reference test piece, obtaining the propagation velocity according to the velocity-thickness corresponding relation and calculating location coefficients; 6 measuring the maximum velocity and the minimum velocity of a test piece to be measured and obtaining the propagation velocity of the test piece to be measured according to the location coefficients; 7 calculating the thickness of the test piece to be measured according to the propagation velocity of the test piece to be measured through the velocity-thickness corresponding relation curve. The horizontal shear guided wave thickness measuring method can achieve the thickness measuring purpose of the test piece with the thickness less than 10mm.

Description

technical field [0001] The invention relates to a method for measuring thickness with a horizontal shear guided wave. Background technique [0002] Ultrasonic nondestructive testing technology mainly includes body wave testing and guided wave testing. Body waves refer to transverse waves or longitudinal waves. For example, the Chinese invention patent whose publication number is CN101398298A, whose invention title is "Method for Electromagnetic Ultrasonic Thickness Measurement"; the publication number is CN101701809A, whose invention title is "A Machine Measurement Method for Electromagnetic Ultrasonic Thickness Gauge", and the application number is 93206367.5 , the Chinese utility model titled "Electromagnetic Ultrasonic Thickness Gauge" all use the pulse reflection method of body waves to measure the thickness of materials; the principle of body wave thickness measurement is to excite the upper end surface of the test piece through electromagnetic The body wave propagates...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01B17/02
Inventor 翟国富蒋韬宫佳鹏许霁康磊高孝天王吉宇
Owner HARBIN INST OF TECH
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