Piezoelectric principle-based omnidirectional horizontal shear guided wave transducer

A horizontal shearing, transducer technology, applied in instruments, scientific instruments, ultrasonic/sonic/infrasonic waves, etc., can solve the problem of generating the same guided waves, and achieve the effect of small volume

Inactive Publication Date: 2014-11-05
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the sensitive element involved in this patent can only generate SH waves in specific directions (directions perpendicular to the four sides of the square element, namely 0 degrees, 90 degrees, 180 degrees and 270 degrees), and cannot generate the same wave in all directions. wave, and it is an original sensitive element, which can be further used as a sensitive element of various transducers

Method used

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  • Piezoelectric principle-based omnidirectional horizontal shear guided wave transducer
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  • Piezoelectric principle-based omnidirectional horizontal shear guided wave transducer

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Effect test

Embodiment 1

[0019] An omnidirectional horizontal shear guided wave transducer based on the piezoelectric principle, including a plurality of piezoelectric sensitive elements 1 (dimensions such as 2mm×2mm×0.5mm, or 3mm×3mm×0.5mm, with a total outer diameter of 28mm) and temporary adhesive tape base 2, a plurality of piezoelectric sensitive elements are arranged in a circle to form an axisymmetric sensor array, the lower surface of the sensor array is pasted on the temporary adhesive tape base in advance to fix the shape of the sensor array, and the number of piezoelectric sensitive elements is 8 or 16, to ensure that the generated waveforms are continuous and uniform around the transducer. Each individual piezoelectric sensitive element has two electrodes, and the positive and negative electrodes 3.4 are located on the same surface. Wires are used to connect the positive electrodes of all piezoelectric sensitive elements. The electrodes are connected in series, and then all the negative ele...

Embodiment 2

[0021] The piezoelectric sensitive element used in the present invention is cut in the relaxation ferroelectric single crystal material, such as (1-x)Pb(Mg 1 / 3 Nb 2 / 3 )O 3 -PbTiO 3 (PMNT, lead magnesium niobate-lead titanate) and Pb(In 0.5 Nb 0.5 )O 3 -Pb(Mg 1 / 3 Nb 2 / 3 )O 3 -PbTiO 3 (PIN-PMN-PT, lead indium niobate-lead magnesium niobate-lead titanate), the specific polarization and cutting direction are as follows figure 2 (a) shown. [001], [010], [100] and [011] in the figure are the Miller indices representing the crystal orientation in crystallography, (011) represents the Miller index of the crystal plane, and the [011] direction and the (011) plane perpendicular to each other. x, y, z represent the coordinate system where the original crystal is placed, and the z direction is the growth direction of the crystal. First, the crystal is polarized along the [011] direction, that is, the Z direction, and then cut out a plane (011) perpendicular to this direction,...

Embodiment 3

[0023] The invention can be directly pasted on the surface of the measured structure and used for excitation of horizontal shear guided waves. Figure 4 An embodiment of the transducer for a thin aluminum plate is given. First, paste it completely on the surface of the cleaned aluminum plate with 502 and other super glue. After the glue is completely cured and the transducer is firmly bonded to the surface of the aluminum plate, a signal generator can be used to apply a voltage signal with a specified amplitude and center frequency (such as V pp = 40 volts, a five-peak narrow-band waveform with a center frequency of 120 kHz), thereby exciting a horizontal shear guided wave in the aluminum plate. Figure 5 to Figure 8 The experimental results of horizontal shear guided wave excitation in an aluminum plate are given, where the excitation voltage is V pp = 5 volts, center frequencies are 80kHz and 120kHz respectively. in Figure 5 with Image 6 is the test result in the dire...

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Abstract

The invention provides a piezoelectric principle-based omnidirectional horizontal shear guided wave transducer. The piezoelectric principle-based omnidirectional horizontal shear guided wave transducer comprises a plurality of piezoelectric sensing elements and a temporary adhesive tape substrate, the piezoelectric sensing elements are annularly arranged to form an axisymmetric sensor array, each of the piezoelectric sensing elements has two electrodes, and all positive electrodes of the piezoelectric sensing elements are connected in series by a lead; and the piezoelectric sensing elements are cut from a relaxor ferroelectric monocrystalline material according to a certain angle to make the d36 piezoelectric coefficient not 0. The piezoelectric principle-based omnidirectional horizontal shear guided wave transducer can generate uniform and continuous shear guided waves in 360 degrees, and can sense horizontal shear guided waves propagated from any direction. Compared with present omnidirectional horizontal shear guided wave transducers, the piezoelectric principle-based omnidirectional horizontal shear guided wave transducer has the advantages of minimal size, generation of omnidirectional horizontal shear guided waves, and permanent fixation to the surface of a structure or embedding into the inside of the structure.

Description

technical field [0001] The invention relates to an omnidirectional horizontal shear guided wave transducer based on piezoelectric principle. Background technique [0002] The detection or real-time online monitoring method based on ultrasonic guided waves is a commonly used non-destructive testing method, which has a wide range of applications in the fields of structural defect detection, structural damage identification and structural health monitoring. This type of method can realize distributed surface detection with few drivers and sensors, and the process is fast and efficient. The horizontal shear guided wave (SH wave) is a kind of ultrasonic guided wave, in which the zero-order horizontal shear guided wave (SH wave) 0 ) has no dispersion effect, will not be converted to other types of sound waves at the boundary, and has less cluttered echoes, and can be used for nondestructive testing of long-distance structures. At present, the excitation and detection of horizont...

Claims

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Application Information

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IPC IPC(8): G01N29/34G01N29/24
Inventor 周文松袁福国李惠
Owner HARBIN INST OF TECH
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