SU634141A1 - Apparatus for resonance testing of objects - Google Patents

Description

one

The invention relates to a testing technique, namely, devices for resonant testing of objects, and can be used to determine the resonance characteristics of various mechanical structures and assemblies, for example, when checking the quality of an assembly.

Devices are known for resonant testing of objects in which mechanical oscillations with a constant amplitude level of the exciting force and variable frequency i are excited by means of an oscillator in the object. When the frequency of the exciter coincides with the frequency of the own resonance of the object, the amplitude of the vibration of the latter increases sharply, which is fixed by the recording attitudes.

In such devices, the amplitude of the exciting force remains constant over the entire frequency range, as a result of which the power consumed is increased, and the frequency change is performed automatically at a constant sweep speed. Durability of speed

the frequency sweep does not allow to determine the characteristics of the resonances of the test object with high accuracy at relatively low sweep speeds, while at very low sweep cKOpocTscc the test time increases.

The closest in technical essence to the invention is a device containing a series-connected master oscillator with an automatic frequency sweep unit, an amplifier with a controlled transmission coefficient, a causative agent of oscillations, a goal of stabilizing the amplitude of oscillations, and a resonance indicator associated with the frequency scanner and the CL recording the characteristics of resonances 21,

In this device, the frequency sweep speed during the passage of the resonant frequencies is reduced, which makes it possible to improve the accuracy of recording characteristics and shorten the test time. However, the need to work with a constant exciting force throughout

This range leads to excessive power consumption during testing.

To reduce power consumption, the proposed device is equipped with a c-tamping circuit, an output voltage of the amplifier, a switch for connecting the control input of the amplifier to an oscillation amplification circuit or an output voltage control circuit and an associated control unit connected to the vt switch. to the output of the resonance indicator, and the output to the block of automatic frequency sweep.

The drawing is a block diagram of the proposed device for the resonant testing of objects.

It contains a master oscillator 1 with an automatic frequency sweep unit 2, an amplifier 3 with controlled transmission coefficient, a power amplifier 4, a exciter 5 exciter of vibration of the test object 6, a vibration measuring transducer 7, a matching amplifier 8, a resonance indicator 9, an operating unit 1O, an apparatus 11 registrations and switch 12,

The device works as follows.

From generator 1, the signal of a frequency that is changed by unit 2 through amplifier 3 with controlled transmission coefficient and power amplifier 4 is fed to the driver, 5 oscillations. The exciter 5 excites vibrations in the test object 6, which are measured by an external measuring transducer 7. The signal from the vibro-measuring transducer 7 through the matching amplifier 8 enters the recording equipment 11 and the resonance indicator 9.

In the initial position, the control input of the amplifier 3 with the control gain is connected by means of a switch 12 to its own output, and the device operates in a constant voltage mode with a low level of excited vibration and low power consumption.

As the excitation frequency approaches the object's own resonance frequency, the phase of the response signal, determined by the vibro-measuring transducer, will begin to outpace the phase of the excitation signal. The NIN and from the resonance indicator 9 is also supplied a signal to the control unit 10. According to the command block of the control 10, the switch 12 connects the control input amplifier 3 s

controllable coefficient of transmission to the output of the matching amplifier 8. In the VTO case, the device operates in the constant mode of the specified vibration parameter, eliminating the possibility of an object breaking. When the 9O shift is reached between the response signal and the excitation signal, indicating that the scientific research institute has reached the object's own resonance frequency, the frequency sweep is stopped. At this time, the control unit issues a command to the recording equipment 11, which will record the resonance characteristics.

After a corresponding time delay, the control unit re-starts the frequency sweep and switches the device to constant voltage mode until the next resonance.

The use of a device with two modes of operation allows one to reduce the power consumed by the device without increasing the test time and reducing the accuracy of recording the frequency characteristics of the test object.

Claims (2)

1. US Patent No. 3472О63, Cl, 73-67.1, 1967. 2. Abramovich S, F., et al. Multichannel control system of monoharmonic vibroscopes, –Sp .: Vibrostables and vibration exciters, TV All and All Conference on Vibrometry. Kiev, 1969, p. 18-27.