SU1335870A1 - Vibroacoustic checking device - Google Patents

Abstract

The invention relates to non-destructive testing of materials and products. And it can be used for vibro-acoustic testing of various structures. The aim of the invention is to enhance the functional capabilities of the device by measuring the acceleration of the vibration. By making the inner cylinder 1 rigid and shorter in length than the outer one, the inner cylinder 1 and the piezoelectric transducer 5 perform the role. inertial mass. The device starts to work in the accelerometer mode. The corrugated surface of the outer cylinder 2 serves as an elastic suspension. The output signal from the piezo transducer 5 is modulated in amplitude. The amplitude-modulated signal through the detector 9 enters the recording equipment 10. In the detector 9, the low-frequency envelope of the converter 5 carries information about the frequency and amplitude of vibration. Thus, it is possible to conclude about the parameters of the vibrating signal, when exposed to i, latent structural defects appear. 1 silt o (L guchchh 00 00 el 00 00, jj.

Description

The invention relates to non-destructive testing of materials and products and can be used for vibro-acoustic testing of various structures. . .

The purpose of the invention is to expand the functionality of the device by measuring the acceleration of vibrations

The drawing shows a block diagram of a device for vibro-acoustic control with. .

The device for vibroacoustic control comprises a housing made in the form of an inner cylinder 1, coaxial with it, an outer cylinder 2 and a flat ring 3, tightly and rigidly connecting non-working ends of the cylinders. On the outer cylinder 2 made in the form of a sylphon, an elastic gasket 4, on the inner cylinder 1 - combined piezoelectric transducer 5 connected to. ultrasonic vibration generator 6, frequency meter 7, voltmeter 8, detector 9 and recorder 10, and matching element 11 o is connected between voltmeter 8 and generator 6

The device works as follows

Before starting measurements by applying pressure to the upper part of the cylinders 1 and 2, they compress the corrugated wall of the cylinder 2 in such a way that the elastic gasket and the lower one. In the drawing, the piezoelectric transducer base 5 was at the same level. After the pressure was stopped, the inner cylinder 1 with the piezoelectric transducer 5 hermetically fixed in its lower base took a certain equilibrium position at a distance uR from the test surface t The elastic strip 4 provides. lower air pressure in the cavity between the cylinders p

Due to the difference between the atmospheric pressure acting on the external surface of the piezoelectric transducer 5, and the reduced pressure in the cavity between the cylinders 1 and 2, the device is in close contact with the test surface 12. Then the generator 6 of sinusoidal signals starts to operate in the linear frequency sweep mode. The voltmeter 8 measures voltage on piezo transform 358702.

le 5, the value of which depends on the frequency of the generator 6, the presence of defects in the test area of the test surface 12 and the distance i R

from the bottom base of the piezoelectric transducer to the study area on top of the Hosteo

If there is a controlled

10 of the surface 12 of cracks, cavities and other defects, the resonant frequency of the piezotransducer system — l R — the investigated area of the test surface is shifted. Minimum

15 reading of the voltmeter 8 indicates the occurrence of a resonance, the frequency of which is measured by a frequency meter 7 "The deviation of the resonant frequency from the corresponding technical conditions

20 values indicate the presence of defects in the test area of the test surface 12,

Thus, if the controlled surface is not exposed

25 vibrations, the claimed device works as a defect analyzer

When the investigated surface area is subjected to vibration, the inner cylinder f and the piezo transducer 5 perform the role of an inertial mass and the device starts to operate in the accelerometer mode. The corrugated surface of the outer cylinder 2 performs the role of an elastic suspension. In this case, the distance, i R varies in magnitude, and the output signal of the receiver of ultrasonic vibrations of the piezotransducer 5 is modulated in amplitude. The amplitude-modulated signal through the detector 9 enters the recorder .10.

Detected by detector 9 low-frequency informative envelope of the signal of the receiver of ultrasonic oscillations, the research institute carries information about the frequency and amplitude of vibration. As a recording equipment can serve as a light beam oscilloscope. According to the indications of recording equipment

CQ can be inferred about the parameters of the vibrosignal, under the influence of which the latent structural defects are projected.

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Claims (1)

Invention Formula A device for vibro-acoustic testing of products, comprising a body made of two coaxial qi. .1 linders, of which the outer is laid out in the form of a bellows and a flat ring, hermetically connected to the non-working ends of the cylinders, an elastic gasket attached to the working end of the outer cylinder, a combined piezoelectric transducer placed in the inner cylinder, a frequency meter connected in series by a voltmeter , the matching element and the generator of ultrasonic vibrations, the output connected to the inputs of the frequency meter. Editor P.Gepsh Compiled by L. Kondrykinsk Hehred M. Didyk 4041/37 Circulation 776 ... VNISh State Committee of the USSR for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d 4/5 Production and printing company, Uzhgorod, st. Project, 4 0 A voltmeter and a combined piezo transducer, characterized in that, in order to extend the functionality by measuring the acceleration of the vibrations, it is equipped with a series-connected detector, whose input is connected to the output of the ultrasonic oscillator, and a recorder, and the inner cylinder is made hard and short than the outer qi; lindr Proofreader S. Cherni Subscription