RU2552600C2 - Bench for study of viscoelastic properties of metals and alloys using acoustic sonde method - Google Patents

Abstract

FIELD: test equipment.

SUBSTANCE: present invention relates to the field of metallurgy and mechanical engineering. The task to be solved by the declared invention is the determination of viscoelastic properties of metals using the acoustic sonde method. The stand for study of viscoelastic properties of metals consists of the variable signal setting generator, an induction mechanical oscillator the elastic element of which is designed as a thin metal beam with a shock sonde fixed on it, and also a sample for study to which the piezoelectric sound pickup is connected. The signals from the generator and the sound pickup are sent to the two-channel computer oscillograph.

EFFECT: technical result is the possibility of non-destructive diagnostics of viscoelastic properties of metals and alloys by means of measurement of amplitude of the acoustic signals occurring at impact of the sonde onto the solid body surface.

5 cl, 3 dwg

Description

The present invention relates to the field of metallurgy and mechanical engineering.

The problem to which the invention is directed, is the determination of the viscoelastic properties of metals using the probe acoustic method.

This problem is solved due to the fact that the design of the bench for studying the viscoelastic properties of metals consists of a generator that sets an alternating signal, an induction mechanical oscillator, the elastic element of which is made in the form of a thin metal beam with a shock probe fixed to it, and also a sample for study, to which a piezoelectric pickup Signals from the generator and pickup are fed to a two-channel computer oscilloscope.

The signal from the generator can be sinusoidal or rectangular.

The shock probe should be made of solid material, such as corundum or diamond.

The radius of curvature of the tip of the shock probe is 100 μm or more.

A piezoelectric pickup is mounted on the surface of the test sample.

The technical result provided by the given set of features is the possibility of a non-destructive diagnosis of the viscoelastic properties of metals and alloys by measuring the amplitude of acoustic signals that occur when a probe hits a solid surface.

The invention is illustrated by drawings, which depict:

Fig. 1 is a block diagram of the stand;

Fig. 2 - waveforms of signals;

Fig. 3 shows the dependence of the intensity of acoustic emission on the amplitude of probe oscillations for some metals.

The design of the stand for the study of the viscoelastic properties of metals consists of the following parts: variable signal generator 1; induction mechanical oscillator 2, shock probe 3; test sample 4; piezoelectric pickup 5; two-channel computer oscilloscope 6.

The operation of the device is as follows.

From the master oscillator, an alternating sinusoidal signal is fed to the induction mechanical oscillator coil, the elastic element of which is made in the form of a thin metal beam. As a result of this, the probe mounted on the beam performs mechanical vibrations, striking the surface of the test sample. The amplitude of the beam vibrations depends on the magnitude of the alternating voltage applied to the coil. The pickup measures the intensity of surface sound waves caused by the impact of the probe on the surface of the sample. Signals from the generator and pickup are fed to a two-channel computer oscilloscope.

The acoustic emission signal during measurements depends on the initial probe – sample distance. This distance is set as follows. A probe oscillating with a minimum amplitude is fed to the sample with a microscrew, and the acoustic emission signal is measured. The probe – sample distance is fixed at the moment when the emission intensity reaches its maximum value.

The measurement result is the dependence of the amplitude of the acoustic signal that occurs when the probe hits the surface of the test sample, on the amplitude of the exciting signal. At low amplitudes of the probe oscillations, this dependence is linear. The slope angle of the obtained characteristics determines the elastic properties of the test sample (transverse sound velocity and elastic modulus). A decrease in the amplitude of the probe’s oscillations with time determines the viscoelastic properties of the sample. The reciprocal of the logarithmic damping decrement clearly correlates with the modulus of elasticity of the test sample.

Thus, the device allows you to simply measure the speed of sound and the elastic modulus of metals and alloys.

Claims (5)

1. A stand for studying the viscoelastic properties of metals, characterized in that it consists of a generator that sets an alternating signal, an induction mechanical oscillator, the elastic element of which is made in the form of a thin metal beam with a shock probe fixed to it, and also a sample for research, to which the piezoelectric a pickup, and the signals from the generator and pickup are fed to a two-channel computer oscilloscope. 2. A bench for studying the properties of metals according to claim 1, characterized in that the alternating signal of the generator can be sinusoidal or rectangular. 3. A bench for studying the properties of metals according to claim 1, characterized in that the shock probe is preferably made of corundum or diamond. 4. A bench for studying the properties of metals according to claim 1, characterized in that the radius of curvature of the tip of the shock probe is preferably 100 μm or more. 5. A bench for studying the properties of metals according to claim 1, characterized in that the piezoelectric pickup is mounted preferably on the surface of the test sample.

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