SU1585692A1 - Method of measuring amplitude of axially symmetric objects - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure the vibrations of assemblies, parts and parts of devices. The aim of the invention is to improve accuracy by taking into account the direction of vibration, mainly for objects of cylindrical shape with an arbitrary direction of vibration in one plane. The method consists in simultaneously irradiating the object under study with two probing microwave signals with different polarization planes from sources operating in the autodyne detection mode, measuring the magnitudes of the detected signals, which determine the amplitude of vibrations. 3 il.

Description

The invention relates to a measurement technique and can be used to measure the vibrations of assemblies, parts and parts of devices.

The purpose of the invention is to improve the accuracy of measuring the amplitude of vibrations by taking into account the direction of vibration mainly for objects of cylindrical shape with an arbitrary direction of vibration in one plane.

 FIG. 1 shows schematically a device for realizing a method for measuring the amplitude of vibrations of axisymmetric objects; in fig. 2 shows the dependence of the detected signal on the ratio of the distance X from the window plane to the surface of the vibrating rod to the wavelength

Microwave radiation

Fig, 3 - the camera with the rod in the equilibrium position and with a maximum deviation in

the process of vibration, the cross section.

Sources. Microwave radiation and simultaneously receivers of signals interacting with a vibrating object — autodyne generators 1 and 2, are segments of a standard rectangular waveguide, which are shorted from one end and have adjustable trimming pistons, and the other end is connected to chambers 3 and 4 made of a metal band rolled up in a ring.

In chambers 3 and 4, a cylindrical metal rod 5 is placed, the movement of which inside chambers 3 and 4 causes a change in the detected probing microwave signal. The rod 5 is located in the chamber 3 so that the axes of the rod and the waveguide are mutually perpendicular and lie in common

ate

00 1SD

a plane passing through the midpoints of the narrow walls of a rectangular waveguide. The rod 5 is either the object itself being tested for vibration, or it can be connected by means of a rigid connection (bracket 6) to the object under study 7, which is outside the chamber 3.

The microwave source 1 is powered by the power source 8.

The second source of microwave 2 oscillations, together with the camera 4 and the power source 9, are identical in design and properties to the first source 1 of microwave oscillations. Chambers 3 and A, made of a metal tape rolled up in a ring, are attached to the wide walls of a rectangular waveguide window 10.,,

The method of measuring the amplitude of vibrations of asymmetric objects is implemented as follows using the proposed device.

Previously, prior to the beginning of the studied vibrations, the plots of the detected signal are plotted against a positive displacement X /; | where

L is the wavelength of the microwave autodyne 1, the rod 5 in the ZIL chambers when the rod 5 is irradiated by the probing microwave radiation from the sources of microwave signals 1 and 2. In FIG. 2 is a graph of

dependencies for the first source of the microwave signal (for the second source of the SBS signal, the graph is similar, since both devices are identical, although in the general case the requirement that the characteristics of both devices are identical is not necessary). Shown in FIG. 2 KLMNP dependency is non-monotonic and contains

plot L-M, the most suitable for measuring the amplitude of vibration using this method. The section K-L, although it has the greatest steepness of the characteristic and a large range of variation of the values of the detected signal U, is not suitable for measurements, i.e. corresponds to the closest approximation of the vibrating object (rod) to the waveguide flange, as a result of which they can touch each other, which is unacceptable. The N-P area and the subsequent areas are less suitable for measurements due to the small diazone of the change in the detected signal. In section L-M, a similar operating point Q is selected, which

corresponds to the equilibrium position of the rod during vibration.

Calibration of the measuring device reduces to the experimental determination of the coefficients:

a, (X) 4U, / LH ,; b, (Y) 40; , (one)

0 (for the first microwave source) and coefficients:

(X).,; bj, (Y) 4U, VY (2)

f5 (for a second microwave source). For this, an object (rod) irradiated with a probe microwave signal, as shown in FIG. 3, are sequentially moved from the starting position

20 (equilibrium position with coordinates X, 0) and the distance iJX, along the X axis, and the increment of the detected microwave signal dUf and U is measured. Then the object (rod) is moved to

25, the distance JY, along the Y axis, is measured by the increment of the detected microwave signal 4Uy (using generator 1) and GSI, (using generator 2). From the obtained values of dX and 3Y., And so ... l1tL .l. L ..

thirty

same

35

Uf, -3U5, JU, the coefficients a, (X), b (Y) a (X) are calculated

1 / „P1. V /)

, according to equalities (1) and (2). Any displacements of gZH and 4Y within the L-M segment satisfy the system of equations:

XU JU, a, (X). GZX + bj (Y), 4Y

XV, (3)

U, j a (X) .X + bj (Y) -. 3Y J

Y Y XY

where, Uj, are the detected signals when the object (rod) is successively moved along X and Y, respectively, for autodyns 1 and 2–45 a (X), –b (Y), and (X) -, b / Y) are coefficients determined during the calibration phase;

4X, / 5Y - measured displacements

within the L-M section of the calibration curve (Fig. 2).

Calibration is performed at the beginning once only to find the coefficients (1) and (2). All subsequent measurements are reduced to reading the indications of the resulting indicators.

Lee and Lee signals detected (with arbitrary movement of the rod). The joint solution of the system of equations (3) by the measured di and

0

1

Editor L.Pcholinsk

Fig.z

Compiled by E.Voronin

Tehred L. OliynyK Proofreader A.Obruchar

Claims (1)

Claim 15 The method of measuring the vibration amplitude of axisymmetric objects, which consists in the fact that the test object is irradiated with probing microwave radiation, the microwave radiation scattered by the test object is recorded, the parameters of which determine the vibration amplitude, characterized in that, in order to improve measurement accuracy by taking into account the direction of vibration vibration can be calculated from the following ratio: '1 a, (X) b, (Y) \ | a ₂ (X) b ₂ (Y). s ^x _{h a} , (X) whether, and _r (X) a ₍ (X) a _r (X) b, (Y) l ^b _r (Y) | / It is also possible to determine the direction of oscillations in the transverse plane of the rod according to the formula: radios, the studied object is irradiated simultaneously with two sounding microwave signals with orthogonal polarization planes, the microwave radiation scattered by the studied object is recorded in autodyne detection mode in two mutually orthogonal planes, and the vibration parameters are determined by a nonlinear algorithm using the results of autodyne detection and calibration coefficients. . Proofreader A. Obruchar