SU930038A1 - Device for testing articles for random wide-band vibration - Google Patents

Description

(S) DEVICE FOR TESTING PRODUCTS

FOR RANDOM BROADBAND VIBRATION

one

The device relates to a vibration test technique and can be used in any branch of engineering.

A device for testing products against the effects of a broadband random vibration is known, comprising a series-connected noise generator, an excitation signal generation unit, a vibrating table, a vibration sensor signal analysis unit and an automatic control unit l.

The drawback of the device is the low quality factor of the forming and analyzing filters, as well as the low accuracy of the formation and reproduction of the energy spectrum, due to the mutual influence of the filter characteristics of the channels of the formation of the excitation signal.

The closest in technical essence to the invention is a device for testing products for random broadband vibration.

containing two white noise generators, odd and even forming channels, each of which includes a series-connected band-pass filter and an adjustable amplifier, the outputs of which are connected to the inputs of an adder connected to the vibrating wall, a vibration sensor connected through the matching amplifier to the inputs of the analyzing channels, each of which includes serially connected bandpass filter, dispersion meter and comparison unit, the outputs of which are connected to the control inputs of the adjustable amplifier according to forming channel L2J.

The disadvantage of this device is the low accuracy of the formation of the energy spectrum of vibration, due to the dependence of the formed spectrum on the amplitude-frequency characteristics (AFC) of the band-pass filters forming it. Since the leading and trailing edges of the frequency response of filters have the form of smooth curves, in the passband of adjacent filters, overlapping zones appear, reducing the accuracy of spectrum formation. The purpose of the invention is to improve the accuracy of the formation of the energy spectrum of vibration. This goal is achieved by the fact that a device for testing products for random wideband vibration, containing two white noise generators, odd and even forming channels, each of which includes series-connected Band-pass filter and an adjustable amplifier, whose outputs are connected to the inputs of the adder, connected to the vibrostand, the vibro sensor, connected through a matching amplifier to the inputs of the analyzing channels, each of which includes series-connected bandpass filter, dispersion meter and block Comparisons whose outputs are connected to the control inputs of adjustable amplifiers of the respective shaping channels are provided with a sinusoidal signal generator and two selective circuits with adjustable ohmic resistance, the signal inputs of which are connected respectively to the first and second white noise generators, and the control ones - to the outputs of the generator of a sinusoidal signal, the output of the first selective circuit is connected to the inputs of the odd 1 forming channels e the output of the second selective circuit to the inputs of even pho miruyuschih channels 1 is a block diagram of the device; in fig. 2 and 3 diagrams of spectral densities of filter output signals. A device for testing products for the effects of random broadband vibration contains two generators 1 and 2 of white noise, two electoral circuits 3 and with adjustable ohmic resistances, the signal inputs of which are connected respectively to the first and second generators 1 and 2 of white noise, the generator 5 sinusoidal signal, the outputs of which are connected to the control inputs of the ohmic resistances of measuring circuits 3 and odd 6 and even 7 forming channels, each of which includes series-connected bands A filter 8 and an adjustable amplifier 9.d the first selective circuit 3 is connected to the inputs of the odd forming channels 6, the output of the second selective circuit is connected to the inputs of the even forming channels J connected in series to the adder 10, the vibrating table 11, the vibration sensor 12, the matching amplifier 13 and analyzing channels 1, each of which includes a series-connected filter 15, a dispersion meter 16 and a comparison unit 17, the inputs of the adder 10 being connected to the outputs of the forming channels 6 and 7 and the outputs of the analyzing channels l key to the control inputs of the adjustable amplifiers 9 in each channel 6 and forming running 7Ustroystvo-follows follows. The signals of white noise generators 1 and 2 with a uniform spectrum arrive at the inputs of the selective circuits 3 and C, the ohmic resistance of which can be controlled by an external control signal, the source of which is the generator 5 of a sinusoidal signal having two anti-phase outputs. As a result of a change in the value of the ohmic resistance in the electoral circuit 3 and the output signal has a rugged spectrum (Fig. 2). When controlling the ohmic resistances of the antiphase signals, the spectra of the outgoing signals of the electoral circuits of ZIL have an offset of bursts by the value of /, (fig. Za, b) where O. is the frequency of the harmonic control signal at the outputs of the generator 5; arriving at forming channels 6 and 7, have non-uniform, and the jagged spectra and O. are consistent with the corresponding frequency response of band-pass filters 8 (fig.c, d) odd and even forming channels 6 and 7- As a result of matching the spectrum of input signals with Frequency response bands These filters increase the autonomy of the shaping channels 6 and 7 due to the weak penetration into each channel of signal formation from adjacent channels (Fig. 3e), which increases the accuracy of the formation of the spectrum of vibrations. The signal from the output of the adder 10 is supplied to the shaker 11 and then through

the vibration sensor 12 and the matching amplifier 13 to the analyzing channels 1A, where the signal is filtered through the channels. The signal from the band-pass filters 15 through the dispersion meters .16 is fed to the first inputs of the comparison blocks 17, to the second inputs of which the reference values of the dispersion in this band are received. From the outputs of the comparison units 17, the error signal is fed to the control inputs of the adjustable amplifiers 9 in each forming channel 6 and 7 where a predetermined level of the generated signal is established by varying the gain. The use of the device allows to increase the languor of the formation of the vibration spectrum by increasing the autonomy | Formation channels by preliminary correction of the signal spectrum of the noise generators.

Claims (2)

1. USSR author's certificate No. 19755, cl. G 01 M 7/00, 197. 2. US patent N 31b3809, cl. 318-132, 1964 (prototype}., V ll J. II 1 11 I I SfHiij I J about. " " . eleven t iI I X h I N. hch Y | H I x X: I  4 1 | H; /14 I / ir lg gz