Transducer for exciting and receiving multimode ultrasonic guided waves in pipe

A technology of ultrasonic guided waves and transducers, applied in the generation of ultrasonic/sonic/infrasonic waves, material analysis using sound waves/ultrasonic/infrasonic waves, instruments, etc., can solve the problems of large volume, heavy quality, and high cost

Inactive Publication Date: 2013-05-01
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The above method 1 brings inconvenience to on-site detection. For example, for a set of transducer arrays for 24-inch pipeline detection, a single-ring transducer array is required to arrange at least 56 transducers. If the minimum 2-ring transducer array is used In order to realize the excitation of different modes of guided waves, at least 112 transducers must be disassembled and reinstalled, which will seriously affect the efficiency of on-site detection
The above method 2 adopts the multi-ring transducer array design, which makes the transducer array complex in structure, large in size, heavy in weight and high in cost

Method used

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  • Transducer for exciting and receiving multimode ultrasonic guided waves in pipe
  • Transducer for exciting and receiving multimode ultrasonic guided waves in pipe
  • Transducer for exciting and receiving multimode ultrasonic guided waves in pipe

Examples

Experimental program
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Embodiment 1

[0026]In this embodiment, the first shear piezoelectric wafer 2 is used to apply an axial load to the pipeline to excite the L(0,2) mode guided wave, and the second shear piezoelectric wafer 3 is used to apply a tangential load to the pipeline. The load is to excite the T(0,1) mode guided wave. In order to ensure that a sufficient number of transducers can be arranged on the outer wall of the pipe with different outer diameters to suppress the bending mode guided wave, the length direction of the transducer in this embodiment is along the The pipes are arranged axially.

[0027] Transducer structure and design: such as figure 2 As shown, it is a transducer for applying multi-directional loads to hollow cylindrical structures such as pipes provided by the present invention, including a protective gasket 4, a first shear piezoelectric wafer whose polarization direction is consistent with the vibration direction 2. The second shear piezoelectric chip whose polarization directio...

Embodiment 2

[0039] In this embodiment, the first shear piezoelectric wafer 2 is used to apply a tangential load to the pipeline to excite the T(0,1) mode guided wave, and the second shear piezoelectric wafer 3 is used to apply an axial load to the pipeline. The load is to excite the L(0,2) mode guided wave, the length direction of the transducer is arranged along the axial direction of the pipe, the polarization direction of the first shear piezoelectric wafer 2 is along its width direction, and the second shear piezoelectric wafer 3 polarization direction along its length direction;.

[0040] Parameters of the tested pipeline 11: inner diameter 206mm, wall thickness 6.5mm, length 5m, material 20# steel, no damage.

[0041] The structure and design of the transducer, the transducer array structure and installation position on the pipeline, the guided wave excitation signal used, the excitation frequency, and the method of exciting and receiving the guided wave are all the same as those in...

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Abstract

The invention discloses a transducer for exciting and receiving multimode ultrasonic guided waves in a pipe, and belongs to the technical field of non-destructive testing. The transducer is characterized by comprising two shearing piezoelectric wafers, wherein the two shearing piezoelectric wafers are horizontally arranged up and down; the vibration directions of the two shearing piezoelectric wafers are the same with respective polarization directions thereof; the polarization directions of the two piezoelectric wafers are mutual orthogonal; and the two piezoelectric wafers are electrically isolated from each other through an isolation layer positioned therebetween. Execution signals are applied on the two piezoelectric wafers respectively, so that the transducer can load different directional loads needed by exciting different mode guided waves on the surface of a detected structure, and the different mode guided waves transmitted along the axial direction of the detected structure can cause the vibration of the piezoelectric wafers to generate voltage signals for analyzing and processing when the main vibration direction of the piezoelectric wafers is the same with the polarization direction of one piezoelectric wafer. The transducer has the effects and the benefits that single one-way guided waves with different modes can be excited and received in the structure through mounting three circles of transducer arrays once along the axial direction of the detected structure, the application is simple, and the scene detection efficiency is high.

Description

technical field [0001] The invention belongs to the technical field of non-destructive testing, and relates to a transducer for exciting and receiving multi-mode ultrasonic guided waves in pipelines, thin-wall thin tubes and other hollow cylindrical structures. Background technique [0002] Ultrasonic guided wave technology can realize rapid non-destructive testing of hollow cylindrical structures such as pipes. This technology uses the principle of pulse-echo. By arranging transducers or transducer arrays somewhere in the structure, it can realize the global inspection of the structure within tens of meters. Detection, high efficiency and low cost. [0003] A guided wave propagating axially in a hollow cylindrical structure has multiple modes. Take the pipeline as an example, such as figure 1 Shown is the group velocity dispersion curve of the guided wave in the 40# steel pipe with an inner diameter of 53mm and a wall thickness of 3.5mm at 0-150kHz. It can be seen from t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N29/34G01N29/22
Inventor 武湛君马书义王奕首
Owner DALIAN UNIV OF TECH
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