SU896515A1 - Device for measuring inner friction - Google Patents

Description

The invention relates to a measurement technique, namely to the study of internal friction of materials, and can be applied in the study of the structure of materials in mechanical engineering, industrial electronics, solid state physics, etc. A device is known that contains a transducer of mechanical oscillations of a sample and a discriminator to isolate oscillations in specified amplitude limits. Capacitive or inductive C 1 sensors are used as transducers. A device for measuring internal friction, containing a sample mechanical vibration transducer, a discriminator and a counter 2, is the closest to the proposed technical essence and the achieved result. A disadvantage of the known device is low measurement accuracy, which This is caused by the operation of the device in the semi-automatic mode and the change in the zero position of the sample, the effect of temperature on it. The purpose of the image is to improve measurement accuracy. The goal is achieved by the fact that the device is equipped with a second discriminator, a reversible counter, connected to the outputs of the prototype. connected to the output of the second discriminator, an adder connected to the outputs of the reversible counter and the second discriminator via the control unit, a command node connecting the reversible counter and a converter, and a generator of tags connected to the input of the counter. FIG. 1 shows a device for measuring the internal friction of samples, which is characterized by a change in the zero position during oscillations; in fig. 2 - voltage diagrams in the absence of zero position drift; in fig. 3 shows voltage diagrams in the presence of zero position drift.

The device contains a sample oscillation transducer 1 (not shown in the electrical signal, the discriminator 2 of the upper and lower levels of the amplitudes of the oscillations, counter 3, the second discriminator k of the zero level controlling the reversible counter 5, the adder 6, the control unit 7 for setting the counter zero zero and the adder 6 , the command node 8, which moves the transducer 1 following the drift of the zero position of the sample, the generator 9 marks, the indicator 10 drift of the zero position of the sample.

The operation of the device is as follows.

In the absence of zero-position drift, the signal decreasing in amplitude (Fig. 2) from the output of converter 1 enters the input of the discriminator 2, which separates the oscillations U that are in the range of the upper and lower levels. Amplifiers arrive at the input of the counter 3 Pulses at the discriminator output Uj, corresponding to each oscillation, have a duty cycle equal to two. The outputs of counter 5 receive pulses for summing and subtracting and. The change in the signal Ujj in the presence of a drift of the zero position of the sample is shown in Fig. 3. In this case, the pulse duty cycle at the discriminator output of torus k is not equal to two, but greater or less than this value. Therefore, the number of summed pulses is not equal to the number of subtracted and, after the end of the subtraction, the readings of counter 5 are not equal to zero. The control unit 7 provides for the cyclical operation of the counter 5 and the adder 6 for every two periods of oscillation of the sample. After the first period, the number of pulses in the counter 5 is proportional to the time difference between the first and second halves of this period. It is sent to node 8 to control the position of transducer 1. Adder 6 adds these numbers for each cycle and outputs to indicator 10 a total value proportional to the total drift of the zero position of the sample. In the case of large frequencies of oscillations of the sample, the signal from the output of the discriminator i can be sent through an integrating amplifier (not shown) to the input of the command node 8,

The positive effect of the proposed invention is due to an increase in the accuracy of measuring internal friction in the presence of a zero drift of the sample during its oscillations.

invention formula

A device for measuring internal friction, comprising a sample mechanical oscillation transducer, a discriminator and a counter, characterized in that, in order to improve measurement accuracy, it is provided with a second discriminator connected to the converter output, a reversible counter connected to the second discriminator output, an adder connected to the outputs of the reversible counter and the second discriminator through the control unit, the command node connecting the reversible counter and the converter, and the generator of tags, connecting Yuchennym k.vhoduy counter

Sources of information taken into account in the examination

1.Aleksandrov L.N. and others. Internal friction and defects in semiconductors. Science% Novosibirsk, 1979,

with. 12.

2. In the same place 12-19 (prototype).

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Claims (1)

Claim A device for measuring internal friction containing a transducer of mechanical vibrations of the sample, a discriminator and a counter, characterized in that, in order to increase the accuracy of the measurement, it is equipped with a second discriminator connected to the output of the transducer, a reversible counter connected to the output of the second discriminator, an adder connected to the outputs of the reversible counter and the second discriminator through the control unit, the command node connecting the reversible counter and the converter, and the tag generator is connected to the input of the counter.