SU1370592A1 - Device for measuring vibration parameters - Google Patents

Description

(21) 3947708 / 2A-09

(22) 08/19/85

(46) 01/30/88. Bul

№ 4

(72) Yu. P. Shchurov, G. A. Malikov, and N. S. Danilin

(53) 621.396.67 (088.8)

(56) Instruments and Systems for Measuring Vibration, Noise and Impact: A Handbook / Ed. V.V. Klyuev. M .: Mashinostroenie, 1978, v. 2, p. 45-47.

USSR Author's Certificate No. 381039, cl. G 01 R 25/00, 1973.

(54) DEVICE FOR MEASURING VIBRATION PARAMETERS

(57) Invention m. used for contactless study of the parameters of the vibration of electrically constructively complex objects. The purpose of the invention is to increase the localization of measurements and ensure the measurement of resonant levels of oscillations with a change in the vibration frequency during the tests of miniature and microminiature electronic components. The device contains autogenerators 1 and 10, attenuators 2 and 9, directional couplers 3.6 and 8, detector sections 4 and 11, filters 5 and 7, registration block 12, switch 13, horn radiator 14, optical. viewfinder 15, vibrator 16, the investigated el 17. 17. 1 Il.

(L

with

L

eight

00

about ate with

IN9

The invention relates to a technique for measuring vibration parameters by a contactless method and can be used for contactless investigation of vibration parameters of elements of structurally complex objects.

The purpose of the invention is to increase the measurement locality and provide measurement of the resonant levels of oscillations when the vibration frequency is changed during the tests of miniature and microminiature elements.

The drawing shows the structural electrical circuit of the device for measuring vibration parameters.

The device for measuring vibration parameters contains the first autogenerator 1, the first attenuator 2, the first directional coupler 3, the first detector section 4, the first filter 5, the third directional coupler 6, the second filter 7, the second} 1 directional coupler 8, the second attenuator 9, the second autogenerator 10 , the second detection section 11, the registration unit 12, the switch 13, the horn transmitter 14, the optical viewfinder 15, the vibrator 16, the element under study 17.

A device for measuring vibration parameters operates as follows.

The first and second oscillators 1 and 10, the frequencies of which: must be separated in the ratio t 7, 2f,, operate simultaneously or alternately. In the first case, the signal from the centimeter wavelength range f with a frequency f with the first autogenerator is branched by the first and third directional taps 3 and 6 through two channels; to the first detector section 4 and to the receiving-radiating channel of the horn radiator 14, whose geometric axis of the radiation pattern for measuring

0 5 0

5 5

0

the second directional coupler 8 to the second detector section 11 and through the second filter 7 and the third directional coupler 6 - into the receiving-emitting channel of the horn radiator 14. The signal f to the input of the first detector section 4 and the autogenerator does not pass, because the first filter 5 ow It is a band-pass filter of frequency f ,.

The interaction of the element under study 17 with the electromagnetic field emitted by the horn radiator 14 makes it possible to realize a mode of operation in which the perturbations of the carrier frequencies of the first and second autogenerators 1 and 10 are affected only by the condition of their matching with the load. These conditions change with a change in frequency 1 and the level of oscillations of the element under study 17, excited by the vibrator 1 6.

As a result of the forced and resonant oscillations of the structural elements of the element 17 under study, conduction disturbances of the oscillator system of the autogenerator — the object under study — occur, accompanied by dynamically tightening the frequencies of the first and second autogenerators 1 and 10. The first and second autogenerators 1 and 10 transition to the mode of sensitive vibration elements. There is amplitude-frequency modulation of carrier frequency signals f, and f, the envelopes of which are separated by the first and second detector sections 4 and 11. Spectral or temporal analysis of low frequency signals from the outputs of the first and second detector sections 4 and 11 in block 12 registering alternately through the switch 13 provides information on the amplitude of the vibration at the frequencies of forced and resonant vibrations of the structural elements of the element 17,

Use as feel

The voltage is guided by the 1 O element cell of the auto oscillator ment 17. The voltage signal of the frequency of the first auto oscillator 1 to the input of the second detector section 1 1 and the second auto oscillator 10 does not pass due to the second filter 7, which is 55

leads to the fact that the parametric connection between the sensitive element and the load takes place with a significantly higher one + 1

+ (2))

m-

time - sensitivity

you fj. The radiation signal of the second autogenerator 10 after the second attenuator 9 is branched by

body element generator

leads to the fact that the parametric connection between the sensing element and the load takes place with a much higher one + 1,

body element generator

+ (2))

m-

time - sensitivity

transformations, where t, M are the frequency index and the amplitude modulation coefficient, respectively, and, consequently, a wider dynamic range of changes in the envelope signal.

By increasing the sensitivity of the transform (as for dali, (o)

i device m 1 „M 1

fl

and it is possible to do t / m 1) the specified accuracy can be ensured when performing measurements in the far radiation zone. As a result, it becomes possible to establish linear dependences between the determined parameters and the measured amplitude of the envelope signal: namely;

) U, j (0) sinnt; UgCO) Ax (O),

with P

 L

A a

x (0)

de x (0), and (0)

And I), (0), Yys,.

L. S} a, b

With fn

f

L

respectively, the amplitude values of the vibration and the output voltage of the detector signal;

conversion sensitivity; circular frequency of vibration;

respectively, the ranges of dynamic and static tightening of frequencies f and f. oscillators 1 and 10; the distance from the horn radiator 14 to the element under study 17; respectively, the effective reflecting surface of the element under study and the cross-sectional area of the radiation pattern of the horn radiator 14 at a distance L; the power signal supplied to the horn radiator 14;

hardware coefficients. . R

,,., const, a ,, So, therefore, A, 7 A ,, when the frequency is reset

five

0

five

0

five

0

five

0

five

Neither the vibrator 16 allows the device to control the dynamic panorama (field) of the resonant oscillations of objects within S at the carrier frequency f, and to reveal the local position (reference to the object) of each of them at the frequency f .; ,

Horn emitter 14 should be optimal at a frequency f, i.e. at this frequency, the width of the radiation pattern should be minimal with minimum dimensions of the horn radiator opening 14.

To increase the local accuracy of measurements and ensure control of the resonant vibration levels of various elements of a structurally complex object, the device is spatially adjusted when the vibration frequency is changed. The adjustment is carried out by combining the geometrical axis of the horn radiator 14 at the location of the element under study with the optical axis of the optical viewfinder 15 installed on the horn emitter 14, the focal length of which is chosen to be equal to the element under study 17. If the distance is smaller than the focal length L, the image of the surface of the object under study 17 is unsharp and, conversely, such an image is sharp if the distance is equal to or greater than L (,.

To align the device at a distance of LP, the horn transmitter 14 with the optical viewfinder 15 is moved relative to the test element 17 in the direction of increasing the distance between them and, having a sharp image, is shifted in a horizontal plane (L const) so that of the resonances recorded at frequency f ,, were simultaneously recorded at frequency ". The adjustment is completed when the oscilloscope and the spectrum analyzer from the recording unit 12 monitor the maximum signal levels regardless of the on / off position of the key 13.

Visually observable and quantitatively recorded in amplitude and frequency resonant oscillations are related to the element of the surface of the element under investigation, to which the center of the crosshair of the optical viewfinder is directed 15.

The operation of the proposed device in generating a spectrum of carrier frequencies f and f, as well as the elimination of combination links between the channels of the respective autogenerators, is achieved through the use of filters 5 and 7,

The bandwidths of filters 5 and 7 should satisfy the following ratios:

.in,, n

duj d-t-Jo, (1) / yoi, „) - (ujj -);

4Ы „(1+ iiu), (t) / dujj i (w – w). s -sLoJe nP 1 u),), where ysh, (t), ly, p 4uij (t), uuJjo are the ranges of dynamic and static frequency clamping of oscillators 1 and 10, respectively.

With a constant acceleration level of 7g across the table of the vibrator 16 in the frequency range of 5–5000 Hz, the sensitivity threshold of the device reaches 1.0. The measurement error of the device by the amplitude of the displacement tlO%. The accuracy of the frequency measurement is determined by the instability of the frequency of the vibration excitation generator and at a frequency of up to 50 Hz is no worse than 0.5 Hz, at frequencies higher than 50 Hz - up to 1%.

Claims (1)

DETAILED DESCRIPTION OF THE INVENTION A device dp is a vibration parameter measurement comprising a series-connected first oscillator, a first attenuator, the first one. The coupler and the first detector section, as well as the recording unit, the antenna and the vibrator, are different because, in order to increase the measurement locality and ensure the measurement of resonant vibration levels when the vibration frequency is changed during the tests of miniature and micromini- tunic elements, injected into it are the first filter connected in series, the input of which is connected to the second output of the first directional coupler, and the second directional a coupler whose output is connected to the antenna input, a second autogenerator connected in series, a second attenuator, a third directional coupler, a second detector section and a switch, the output of which is connected to the input of the registration unit, and the second input of the switch is connected to the output of the first detector section, the second output of the third directional the coupler is connected in series through the input of the second filter with the second input of the second directional coupler, the antenna being designed as a horn radiator, on the installed optical viewfinder is installed, the optical axis of which intersects the electrical axis of the horn emitter j at the intersection of which the element under study is located, the signal frequency at the output of the second oscillator f5 2f ,, where f, is the frequency of the signal at the output of the first oscillator.