Method for using higher standing wave resonance for quantitatively detecting thickness of elastic plates

A quantitative detection, elastic plate technology, applied in the direction of using ultrasonic/sonic/infrasonic waves, measuring devices, instruments, etc., can solve the problems of shallow detection depth, inability to detect the surface corrosion of non-conductive materials, and needs to be improved

Active Publication Date: 2010-08-18
NANJING ZHUOSHI ELECTRIC +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the x-ray diffraction method is harmful to the human body, and the detection depth is relatively shallow (25-40 microns in steel materials); the accuracy of the neutron diffraction method for detecting residual stress is similar to that of x-rays, and its detection depth is deeper than that of x-rays (

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  • Method for using higher standing wave resonance for quantitatively detecting thickness of elastic plates
  • Method for using higher standing wave resonance for quantitatively detecting thickness of elastic plates
  • Method for using higher standing wave resonance for quantitatively detecting thickness of elastic plates

Examples

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Effect test

Embodiment 1

[0062] Take the aluminum plate with the thickness of the tested elastic plate in the range of about 20cm, and its density is 2700kg / m 3 , The longitudinal wave speed is 6420m / s, if the material is the thickness direction sheet-shaped longitudinal wave piezoelectric transducer of zinc oxide (density is 5680kg / m 3 , The longitudinal wave velocity is 6400m / s, the electromechanical coupling coefficient is 0.3), then according to Vl sb / V sb l>100, the thickness of the selected sheet-shaped longitudinal wave piezoelectric transducer is about 0.2mm.

[0063] The thickness detection accuracy of the elastic plate is required to be 20μm. Use the known plate-shaped piezoelectric layer and the material constant of the elastic plate to be tested, and set l a Take 20cm and d and take 20μm into formulas (2) and (3) to determine the frequency resolution of the impedance analyzer or network analyzer f min About 1kHz; using the impedance frequency spectrum spliced ​​after segmented continuous sca...

Embodiment 2

[0066] Take the steel plate whose thickness range of the tested elastic plate is about 20cm, and its density is 7800kg / m 3 , The longitudinal wave velocity is 5900m / s, if the material is PZT5 thickness direction sheet longitudinal wave piezoelectric transducer (density is 7000kg / m 3 , The longitudinal wave velocity is 2400m / s, the electromechanical coupling coefficient is 0.6), according to Vl sb / V sb l>100, according to Vl sb / V sb If l>100, the thickness of the sheet-shaped longitudinal wave piezoelectric transducer is about 0.8mm.

[0067] The thickness detection accuracy of the elastic plate is required to be 20μm. Use the known plate-shaped piezoelectric layer and the material constant of the elastic plate to be tested, and set l a Take 20cm and d and take 20μm into formulas (2) and (3) to determine the frequency resolution of the impedance analyzer or network analyzer f min Is 38Hz; the impedance frequency spectrum spliced ​​after segmented continuous scanning (such as ...

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Abstract

The invention relates to a method for using higher standing wave resonance for quantitatively detecting the thickness of elastic plates, which comprises the following steps: exciting vertical waves in the elastic plates through a sheet-shaped vertical wave piezoelectric transducer; transmitting the vertical waves in the elastic plates to the other surface of the elastic plates to be reflected and forming the standing wave harmonic vibration in the elastic plates; then, using a impedance analyzer or network analyzer for obtaining a higher standing wave resonance modes of the elastic plates; then, calculating the effective electromechanical coupling coefficient of each higher standing wave resonance mode; obtaining the parallel connection resonance vibration frequency of the resonance mode corresponding to the largest effective electromechanical coupling coefficient; and obtaining the thickness of the elastic plates according to the vertical wave sound resistance relationship of the sheet-shaped vertical wave piezoelectric transducer and the detected elastic plates in the thickness direction. The detection of the invention has higher sensitivity, in addition, the equipment is simple and can be easily realized, the sensitivity is high, and the observation is easy. The standing wave resonance of the elastic plates in the invention is sensitive to the surface conditions, and the corrosive conditions of the surfaces of the elastic plates can be marked.

Description

Technical field [0001] The invention relates to a method for detecting the thickness of an elastic plate, in particular to a method for quantitatively measuring the thickness of the elastic plate and detecting the corrosion on the surface of the elastic plate by using high-order standing wave resonance. Background technique [0002] In aviation, petrochemical industry, military and other fields, plate-shaped elastic materials (metal, non-metal and composite materials, etc.) are often used. The quality of these materials is related to their own elasticity and strength, and more importantly, the corrosion of the material surface The potential threat is often the main factor causing the accident. When a tank made of a plate-like elastic material is used for a period of time, the corrosive substances in the container will corrode the inner surface of the tank, and cracks, voids, and potholes will appear on the inner surface. The existence of these defects will affect the tank body. ...

Claims

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Application Information

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IPC IPC(8): G01B17/02
Inventor 张辉张淑仪刘桂梅列剑平
Owner NANJING ZHUOSHI ELECTRIC
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