SU913237A1 - Device for measuring material physical mechanical parameters - Google Patents

Description

The invention relates to acoustic measurements and can be used to measure and control the physico-mechanical parameters of solids.

A device is known for measuring the constant elasticity of solid isotronic bodies, consisting of a receiving-emitting piezoelectric transducer directed at an acute angle to the surface of the body under investigation, a pulse generator, an amplifier and an indicator G13.

The disadvantages of this device are the inability to measure the density of a solid and low measurement accuracy due to the insufficient accuracy of determining the angles of maximum excitation of surface waves.

The closest in technical essence to the invention is a device for measuring the physicomechanical parameters of materials, comprising a pulse generator, a piezotransducer associated with it, a prism and a sequence

2

the first amplifier and recorder Ϊ2].

The disadvantage of this device is the inability to simultaneously measure the density of solids, which is one of the main physico-mechanical parameters.

The purpose of the invention is to expand the functionality by measuring the density of the material.

This goal is achieved by the fact that the device is equipped with an additional piezoelectric transducer and its associated and serially connected selector, second amplifier and voltage ratio meter, the second input of which is connected to the second output of the selector, the prism is made with a reflecting surface parallel to its working face, and an additional piezoelectric transducer is installed on the prism parallel to the sample in such a way that its axis of symmetry passes through the inner edge of the reflecting surface.

913237

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FIG. 1 shows a block diagram of a device for measuring physicomechanical constants of solid tep; in fig. 2 timing diagrams explaining the operation of the device.

The device contains a prism 1, a piezo transducer mounted on it 2, an additional piezo transducer 3. Generator 4 connected in series

pulses connected to a piezo-transform, θ _tepa 9 stress ratio, on the flag 20

2 and 3, the first amplifier 5 and the indicator 6. In addition, the device. contains consistently connected to the selector 7 pulses, the second amplifier 8 and the meter 9 voltage ratio. Additional piezoelectric transducer 3 is connected to the generator 4 pulses and the selector 7 pulses. And the second output of the selector 7 is connected to the significant input of the meter 9 voltage ratio.

The device works as follows.

The pulse generator 4 excites a piezoelectric transducer 2, which radiates ₂₅ into a rectangular sample 10 of controlled material at an angle of incidence ά longitudinal ultrasonic waves 11 and transverse 12.

The prism 1 is moved towards the edge of the sample 10 until one of the types (longitudinal 11 or transverse 12) waves is reflected from the right angle of the sample in the opposite direction. Reflected waves are received by a piezoelectric transducer 2, and at its output, the electric pulses are devalued by the first amplifier 5 and are observed on the screen of the recorder 6 (oscilloscope).

At the moment of observation of the maximum pulse on the screen, measure * the distance X from the point of entry of the ultrasonic beam of the piezo-converter 2 to the edge of the face of the sample 10. After that, the prism 1 is moved to the position in which the maximum reflection from the corner of the sample 10 of transverse waves 12 is obtained, and the corresponding distance X _t (not shown). From the measured values, the velocities of the longitudinal C -> and transverse waves and the Poisson’s ratio M are calculated.

Then from the generator 4 pulses excite the piezoelectric transducer 3, which emits pulses of longitudinal ultrasonic waves 13 and 14. Reflected from the face of a prism adjacent to the air, and from ⁵⁵ working faces of the prism ultrasonic pulses are received by the transducer 3 (Fig. 2a) and fed to the selector input

thirty

35

45

50

7, at the first output of which a pulse is emitted (see Fig. 26) generated by longitudinal waves 13. At the second output of the pulse selector 7, a pulse generated by longitudinal waves 14 is emitted (Fig. 2c). The electrical signal amplified by the second amplifier 8 from the first output of the pulse selector 7 is fed to the numeral input of a conversion input of which an electrical signal is supplied from the second output of the selector. In this case, the gain of the amplifier 8 can be set to ¹⁵ kim, at which, in the absence of the sample 10, the pulses at the inputs of the meter are equal. Then the meter readings in the working position of the sensor are equal to the reflection coefficient V of longitudinal ultrasonic waves from the border between prism 1 and sample 10. And the density and shear modulus μ-, sample material 10 is calculated using the formulas

νΐ-ν) 5ίηά

Gader - the density of the material of the prism 1;

$ is the sample thickness of the controlled material;

ώ is the angle of the prism.

The efficiency of this device is provided in that additional measured density of the material ₄₀ is allowed to determine as to measure the Young's and shear moduli.

Claims (1)

Claim A device for measuring the physicomechanical parameters of materials, containing a pulse generator, a piezotransducer associated with it with a prism and a first amplifier and recorder connected in series, characterized in that, in order to expand the functionality by measuring the density of the material, it is equipped with an additional piezotransducer and associated with him and series-connected selector second amplifier and voltage ratio meter, the second input of which is connected 5 913237 6 with the second output of the selector, the prism is made with a reflective surface parallel to its working face, and an additional piezoelectric transducer is installed On the prism parallel to the sample in such a way that its axis of symmetry passes through the inner edge of the reflecting surface.