SU1158882A1 - Device for testing articles at resonance frequency - Google Patents

Abstract

OSTRS STVO FOR TESTS. EQUIPMENT ON THE RESOIAIS FREQUENCY, containing the output electromechanical converter, the code mechano-electric converter, the nonlinear element, the integrator to the reversible bridge switch, in which one diagonal is connected to the output of the integrator, and the same diagonal plug is connected to the converter, and the same pin on the plug of the non-linear element and the input pin has been connected to the switch. The input of which is connected to the output of the power supply source, which differs from the fact that, with the aim of automating the tests, including in left conditions, by ensuring tolerance control over the values of the frequencies of resonant oscillations of the tested products, device, two comparators are introduced, the first inputs of which are connected to the integrator's output, and the second inputs are connected to the second and third outputs of the power supply, differentiating the circuit whose input is connected to the output of the nonlinear element, the NAND circuit, the inputs of which are connected to the outputs of the comparators and the output of the differentiating circuit, a trigger, in which the counting input is connected to the output of the Y – N circuit, and The setup input is connected to the output of the nonlinear element, the indicator is in the specified range of sd nationals of the frequencies connected to the output of the trigger. eo 00 0

Description

one

The invention relates to a test apparatus and can be used to control the quality of products or to determine the characteristics of buildings by the frequencies of their resonant vibrations.

The kilohertz range setup is known for automatically measuring the logarithmic decrement and Young's modulus in samples of cyindric form when excited in them by resonant beaky vibrations of the fundamental tone, consisting of an amplifier, an automatic gain control unit, an exciter and a receiving electromagnetic transmitter, a distributor, a frequency meter, a master, a frequency meter, a frequency meter, a transmitter, a receiver and an electromagnetic receiver. , measuring amplifier, recorder and dial gauge indicator of the measured amplitude D.

The disadvantage of the installation lies in its comparative complexity, which can only be used for laboratory tests.

Closest to the proposed technical entity is a device for testing products at a resonant frequency, containing an output electromechanical transducer, an input mehoelectric transducer, a nonlinear

an element, an integrator, and a reversible bridge switch, in which one diagonal is connected between the output of the nonlinear element and the integrator input, and the other diagonal is connected to the outputs of the voltage converter in multidirectional currents, the input of which is connected to the output of the voltage supply source D.

The disadvantage of this device is that the operator can judge whether the frequency values fall within the specified boundaries as a result of the comparison of the measured particles with the specified boundary ones, due to

which reduces the reliability of the control and makes it difficult to automate the tests, including in the field.

The purpose of the invention is to automate tests, including in field conditions, by ensuring tolerance control over the frequencies of the resonant oscillations of the tested products.

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This goal is achieved by the fact that a device for testing products at a resonant frequency, containing an output electromechanical

5 converter, input mechano-electric converter, nonlinear element, integrator and reversible bridge switch with one diagonal on

10 between the output of the nonlinear element and the input of the integrator, and the other diagonal is connected to the outputs of the voltage converter in multidirectional currents, the input of which at) 5 is connected to the output of the supply voltage source, two comparator are introduced, the first inputs of which are connected to the output of the integrator, and the second inputs are connected to the second and third levels of the power supply source, a differentiating circuit, the input of which is connected to the output of the nonlinear element, an AND – N circuit whose inputs are connected to the outputs

25 comparators and the output of differentiating depi,; trigger, whose counting input is connected to the output. AND-NOT circuit, and the setup input is connected to the output of the nonlinear element, the indicator falls within the specified range of values of resonant frequencies, connected to the trigger output, pa. ,,

FIG. -1 shows the structures on the scheme of the proposed device; in fig. 2 and 3 are timing diagrams explaining the operation of individual units of the device.

A device for testing products at a resonant frequency contains

output electromechanical converter 1, input mechano-electric converter 2, nonlinear element 3 with relay characteristics, integrator А, reversible bridge switch 5, in which one diagonal is connected between the output of nonlinear element 3 and the input of integrator 4, and the other diagonal is connected to the outputs of converter 6 voltage multidirectional currents, which is attached to; In the source code 7 of the supply voltage, two comparators 8 and 9, the first inputs of which are connected to the output of the integrator 4, and the second inputs are connected to the second and third outputs of the source 7 of the supply voltage 3 1 and the differentiating circuit Ш of the input 3 is connected to the code of the nonlinear element 3 , AND-NOT circuit 11, the inputs of which are connected to the output | Au of the comparators 8 and 9 and the output of the differential circuit 10, trigger 12, in which the counting input is connected to the output of the AND-HE circuit 11, and the setup input is connected to the output of the nonlinear element 3, and indicator 13 hits 13 ingress to the specified range of resonant frequencies, connected to the output of flip-flop 12.

The device works as follows.

Before switching on the device, transducers 1 and 2 are connected to the tested product, as a result of which a closed self-oscillating circuit is formed from blocks 1-5 and the product. When the device is turned on in this self-oscillating circuit, oscillations occur with a frequency determined by the resonant frequency of the fundamental tone of the test article. The amplitude of oscillations of the tested product depends both on its properties and on the magnitude of the signal from the output of integrator 4, which is converted by the transducer 1 into a force applied to the product. The amplitude of the triangular signal at the output of the integrator 4 is determined by the values of the currents flowing through the switch 5. Reversible bridge switch 5 works as a synphragm with switching of the nonlinear element 3, providing alternately connecting the input of the integrator 4 to the outputs of the converter 6 that converts the voltage from the output of the source to 7 multidirectional currents of the same size. Before testing of different types of products, which are characterized by different values of the resonant frequencies of the fundamental tone, the device is tuned to. a certain amplitude U of the signal at the output of the integrator 4. This setting is provided by adjusting the voltage Ug (Fig.2) At the same time, at a constant value and a certain voltage level Uj, its frequency value 4 oscillates in the auto-loopback circuit of the device. After setting, you can carry out admission 88824

control over the values of the resonant frequencies of the fundamental tone of the tested products. For example, you want to sort a product in which

5, the indicated frequencies differ by no more than J: 20% of the value of f. In this case, the voltage U, (1-0.20) and, is applied to the input of the first comparator 8, and, and the voltage Ug, (1 +

+ 0.20) Shch-. If in the tested products the resonant frequencies of the fundamental tone do not differ by more than ± 20% from the value of f, then, consequently, the amplitude U of the signals at the output of the integrator 4 is within b 4 Then for the invoice. arrivals to the inputs of the circuit AND-NOT 11 signals, the form of which is shown in

20 of FIG. 3, at the output of circuit 11, a level O is formed. With this signal, a trigger 12 is set in O, which causes the indicator 13 to flash in the specified range.

5 values of resonant frequencies. In soy- then nyu 1 trigger 12 is translated by a negative polarity signal from the output of nonlinear element 3, arriving at the setup input

0 trigger. As a result, pulses are applied to the indicator 13 at a frequency coinciding with the resonant frequency of the test article. When included in self-oscillating

, the contour of the test article, in which the resonant frequency of the fundamental is, the tone is less than ff by 20% or more, at the output of the integrator 4 signals are generated with an amplitude exceeding Uj. Therefore, at the output of the comparator 9, levels O are formed and, therefore, at the output of the IT circuit there will be 1 (as well as at the output of the trigger 12). As a result, indicator 13 is not displayed.

 will be. If a product is included in the self-oscillating circuit, whose resonant frequency of the fundamental tone is greater than the f value, by 20% or more, then at the output of the integrator 4

 triangular pulses are formed with an amplitude smaller than U. Therefore, on the output of the first comparator 8 there will be a level close in level to O, and, therefore,

5 at the output of circuit 11 will be 1 (as well as at the output of trigger 12). As a result, indicator 13 will not highlight.

The main advantage of the invention is that the value of the resonant frequency of the pitch of the test product can be judged by the amplitude of the signal at the output of the integrator 4. When the resonant frequencies exceed the given deviations, the amplitude of the signal at the output of

Rattor 4 also exits the given Boundaries, which is driven by the first and second comparators. Therefore, the tolerance control over the frequencies of the resonant oscillations of the fundamental tone can be carried out without using the measurement frequency and time intervals.

Claims (1)

DEVICE FOR TESTING PRODUCTS AT RESONANT FREQUENCY, containing an output electromechanical converter, an input mechanoelectric converter, a nonlinear element, an integrator and a reversible bridge switch, in which one diagonal is connected between the output of the nonlinear element and the input of the integrator, and the other diagonal is connected to the outputs of the voltage converter currents, the input of which is connected to the output • of the supply voltage source, which differs in that, in order to automate the test In particular, in field conditions, by providing tolerance control over the values of the frequencies of the resonant vibrations of the tested products, two comparators are introduced into the device, the first inputs of which are connected to the output of the integrator, and the second inputs are connected to the second and the third outputs of the supply voltage source, a differentiating circuit, the input of which is connected to the output of a nonlinear element, an NAND circuit, the inputs of which are connected to the outputs of the comparators and the output of the differentiating circuit, a trigger, in which the counting input is connected to the output ohm-Q NOT circuit, and adjusting the input connected to the output of a nonlinear element in a predetermined hit indicator · range of resonant frequencies, connected to the output of the flip-flop. w □ o eo eo ko 1158882 2