A true time-delay single-mode lamb wave phased array system for detection of slab structures

A structure detection and phased array technology, which is applied to the analysis of solids by using sound waves/ultrasonic waves/infrasonic waves, material analysis by using sound waves/ultrasonic waves/infrasonic waves, and measuring devices. It can solve problems such as changes and complexity, and achieve high detection efficiency. Imaging is intuitive and the effect of enhancing the signal-to-noise ratio

Active Publication Date: 2019-01-08
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the guided Lamb wave in the plate is dispersive, and its wave velocity changes with the thickness of the specimen and the signal frequency. The mode is more complex than ordinary ultrasonic waves and various modes are coupled, such as figure 2 As shown, therefore, the Lamb wave phased array damage detection system needs special design and construction in order to realize the excitation and detection of a single mode

Method used

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  • A true time-delay single-mode lamb wave phased array system for detection of slab structures
  • A true time-delay single-mode lamb wave phased array system for detection of slab structures
  • A true time-delay single-mode lamb wave phased array system for detection of slab structures

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Experimental program
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Effect test

Embodiment 1

[0054] A true time-delay single-mode Lamb wave phased array system for plate structure detection, such as image 3 As shown, it includes: controller 1, multi-channel D / A converter 2, multi-chip Lamb wave phased array probe 3, multi-channel relay 4, multi-channel A / D conversion acquisition card 5, imaging display 6,

[0055] The electrical signal of the controller 1 is connected to the multi-channel D / A converter 2, and the multi-channel D / A converter 2 is connected to the multi-chip Lamb wave phased array probe 3 through the electrical signal of the multi-channel relay 4;

[0056] The multi-chip Lamb wave phased array probe 3 is connected to the multi-channel A / D conversion acquisition card 5 through the multi-channel relay 4 electrical signal, the multi-channel A / D conversion acquisition card 5 is connected to the controller 1 by electrical signal, and the electrical signal of the controller 1 is connected to the imaging Display 6; the multi-channel digital / analog converter c...

Embodiment 2

[0076] The laser Doppler vibrometer (LDV) was used to measure the focusing of the waves excited by the Lamb wave phased array. In the test, the tested metal plate is a 6061 aluminum alloy plate with a density of 2,700kg / m 3 , the elastic modulus E is 69.0GPa, the Poisson's ratio v is 0.33, and the size is 914.4mm×914.4mm×1.6mm. Paste 7 piezoelectric sensors in the middle of the board. The size of each piezoelectric sheet is 7mm×7mm×0.5mm, and the spacing is 1mm to form a true time-delay single-mode Lamb wave active phased array. At the same time, the passive phased array is pasted on the corresponding position on the back of the active phased array to receive the scattered echo of the damage, and detect and locate the damage of the board. Each piezoelectric sensor unit is connected to the wire through a conductive copper tape and connected to the transmitting / receiving instrument - PXIe-1082 produced by National Instruments NI, a total of four acquisition cards: PXIe-6361, PX...

Embodiment 3

[0084] On the basis of the above-mentioned laser vibrometer detection, the passive ultrasonic phased array also starts to perform damage detection on the detected area at the same time. The detection principle of the passive phased array is to receive the reflected echo of the damage, and obtain the geometric parameters such as the size and position of the damage according to the imaging algorithm. This section shows the detection results of different damage situations.

[0085] (1) Test results without damage

[0086] The first is the damage detection results in the case of no damage. The test setup is the same as the above-mentioned laser vibrometer detection test, and the damage identification and positioning of the passive phased array are completed at the same time as the laser detection. The signal received by the passive phased array first passes through a 20kHz-500kHz band-pass filter to filter out low-frequency vibration signals and eliminate high-frequency noise inte...

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Abstract

The invention relates to a true-time-delay single-mode Lamb wave phased array control system used for platy structure detection. The true-time-delay single-mode Lamb wave phased array control system comprises a controller, a multichannel digital / analog converter, a multi-chip Lamb wave phased array probe, a multichannel relay, a multichannel analog / digital conversion collecting card and an imaging display. By the aid of the multi-chip Lamb wave phased array probe, a voltage signal is converted into a wave signal trough the inverse piezoelectric effect and then stimulated in a structure, and meanwhile, the wave signal obtained through damage reflection is converted into an electrical signal according to the direct piezoelectric effect in a receiving process. The true-time-delay single-mode Lamb wave phased array control system has the advantages that narrow-band pulse stimulating array unit is adopted, a specific single mode is selected according to a tuning curve, amplitude of the single mode in a guided wave is enhanced in the detection direction, wave beam deflection and focusing in a real physical field are realized, a spatial domain resolution ratio is increased, and a damage reflection signal is amplified; the true-time-delay single-mode Lamb wave phased array control system is wide in detection range, high in damage sensitivity, direct in imaging and high in detecting efficiency.

Description

technical field [0001] The patent of the present invention relates to a true time-delay single-mode Lamb wave phased array system for plate structure detection. Background technique [0002] Ordinary ultrasonic testing is a structural damage detection method with a single probe, and the obtained one-dimensional signal cannot be imaged intuitively in a single measurement, while the phased array detection method composed of multiple probes can detect and image structural damage. Ultrasonic phased array damage detection originated from phased array radar in the military, both of which are based on the Huygens principle: one transmits and receives ultrasonic beams for damage detection, and the other uses electromagnetic waves for target tracking. The probe of the ultrasonic phased array is composed of a group of piezoelectric transducer (PZT) units independent of each other, each unit can transmit and receive ultrasonic waves independently, and the phases of ultrasonic waves tra...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N29/06G01N29/24G01N29/34
CPCG01N29/069G01N29/24G01N29/34G01N2291/023G01N2291/042
Inventor 王文韬李惠
Owner HARBIN INST OF TECH
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