SU1401370A2 - Acoustic method of flaw detection - Google Patents

Abstract

The invention relates to non-destructive testing of products. The purpose of the invention is to increase the sensitivity of the control and expand the scope of application due to the possibility of controlling objects from a material with a large attenuation coefficient. The controlled object is cooled, excites mechanical resonant oscillations in it, reveals additional resonance frequencies compared to the defect-free standard, and determines the difference between the additional and basic resonant frequencies of the standard, which is used to judge the presence and size of the defect. The cooling of the monitored object is dried to a temperature that ensures the registration of near resonant peaks, the frequency difference between which is determined by the predetermined sensitivity of the control. with s

Description

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BIO, T. Kontrol.

The acoustic method using standard ultrasound equipment is carried out as follows.

A generator of electrical harmonic oscillations, the frequency of which varies within pre-selected limits, excites a piezo emitter mounted on the core-duct. Oscillations piezo emitter

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The invention relates to the field of flaw detection, can be used to control the homogeneity and continuity of products and is an improvement in the method of auth. St. No. 819709.

The purpose of the invention is to increase the sensitivity of control and expand the scope by providing the possibility of controlling objects from a material with a large attenuation coefficient.

The essence of the acoustic method of defect-10 propagating along the core-conductor from the copy is as follows. It excites oscillations in a controlled object placed in a refrigerating chamber. The oscillations of the object being monitored are perceived through the core-sound conductor by a piezo receiver. When the oscillator frequency coincides with the resonant frequency of the object being monitored, resonance oscillations occur in the latter, whose amplitudes are recorded as secondary equipment, which can be between the main and additional 2o oscillograph or analyzer amplitude resonance peaks. frequency response. The frequency of the ivepax defect. Moreover, the controlled object of the object being monitored is registered; the object is pre-cooled to the temperature with a frequency meter. Thus, the parameters at which the extended detection of resonant peaks, the controlled object are additionally separated by a frequency interval, the minimum 25 resonant peaks are determined in the oscillation spectrum of the cooled, and the minimum value of which is determined in accordance with the predetermined sensitivity of the controlled.

As the temperature decreases, the attenuation coefficient of the mechanical oscillations in the material of the object decreases. This leads to the fact that the quality factor of the controlled object, considered as a mechanical oscillatory system, increases. Therefore, it becomes possible to excite resonant mechanical vibrations in a controlled object and to conduct a control. In addition, the increase

In a controlled object from a material with a large attenuation, mechanical resonant oscillations are excited in a given frequency range of its frequency spectrum, the main and additional resonance peaks are recorded when comparing an object with a defect-free standard, the appearance of additional frequencies is judged by the object’s detectivity, and 30

frequencies between the main and additional frequencies, establish the fact of the presence of a defect in the controlled object and determine its size.

Claims (1)

Invention Formula 35 the quality factor manifests itself in a decrease in the width of the resonant peaks. The latter allows the separation of resonant peaks, due to the presence of defects of smaller magnitude. Acoustic method of flaw detection according to ed. St. No. 8-19709, characterized in that, in order to increase the sensitivity of monitoring and expanding the scope of application by providing the ability to control objects from a material with a large attenuation coefficient, the controlled product is cooled to a temperature that allows separate registration of adjacent resonant peaks. e. increase sensitivity BIO, T. Kontrol. The acoustic method using standard ultrasound equipment is carried out as follows. A generator of electrical harmonic oscillations, the frequency of which varies within pre-selected limits, excites a piezo emitter mounted on the core-duct. Oscillations piezo emitter object placed in the refrigerator. The oscillations of the object being monitored are perceived through the core-sound conductor by a piezo receiver. If the oscillator frequency coincides with the resonant frequency of the object being monitored, resonance oscillations occur in the latter, whose amplitudes are recorded by the secondary equipment, which can be an oscilloscope or amplitude-frequency characteristics analyzer. The frequency of the resonances of the object being monitored is recorded with a frequency meter. Thus, having detected an additional 5 resonance peaks in the oscillation spectrum of the cooled controlled object and determining the difference 0 frequencies between the main and additional frequencies, establish the fact of the presence of a defect in the controlled object and determine its size. Invention Formula five Acoustic flaw detection method according to ed. St. No. 8-19709, characterized in that, in order to increase the sensitivity of monitoring and expanding the scope of application by providing the ability to control objects from a material with a large attenuation coefficient, the controlled product is cooled to a temperature that allows separate registration of adjacent resonant peaks.