SU1295209A1 - Device for determining energy dissipated in material for one cycle of variable loading - Google Patents

Abstract

The invention relates to a measurement technique, namely, to means for determining the mechanical properties of materials. The aim of the invention is to improve the accuracy and expansion of the frequency range in the measurement of energy loss by introducing frequency multipliers 5 that carry the signal. K times, and multiplier 6 1 to K 1 times, followed by their multiplication in multiplication blocks 7 and 8. 1 il. (Ls

Description

one

The invention relates to a measurement technique, to means for determining the mechanical properties of a material, in particular, energy dissipation due to internal friction during cyclic immersion of a sample of the material under study.

The purpose of the invention is to increase the accuracy and expansion of the frequency range in the measurement of energy loss by introducing multipliers of the carrier signal frequency K times and K + 1 times followed by their multiplication.

The drawing shows a schematic diagram of the device.

The device contains a sample deformation sensor 1, the first amplifier 2, the input of which is connected to the output of the deformation sensor 1, the sensor 3 of the mechanical voltage of the sample, the second amplifier 4, the input of which is connected to the output of sensor 3, the frequency multiplier 5 times , whose input is connected to the output of the first amplifier 2, the frequency multiplier is K + 1 times, the input is connected to the output of the first amplifier 2, and the output is connected to the power supply circuit of the sensor 3 of the mechanical voltages of the sample, the first multiplication unit 7, the first input of which is connected with access to The second amplifier 4, the second input - with the first output of the frequency multiplier 5, the second multiplication unit 8, the first input of which is connected to the output of the second amplifier 4, and the second input - with. The frequency output of the frequency multiplier 5, the electronic potentiometer 9 with the measuring bridge circuit 10, the zero organ 11 and the executive motor, Le 12j, the input of the latter is connected to the output of the zero organ 11, and the shaft is connected to the slider of the bridge, the diagonal of the bridge circuit 10 is connected to the output of the second multiplication unit 8, and the signal diagonal is connected to the input of the null organ 11 in series and the output of the first multiplication unit 7.

The device works as follows.

The test sample is loaded with a variable periodic load, varying in a sinusoidal law. In this case, the deformation of the 6 sample, the law changes

S f sincot

1295209. 2

where fm is the amplitude of the deformations; WITH - circular frequency; t - time

Mechanical stresses b vary according to

fO

J5

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b (cJt + cf),

where C is the amplitude of mechanical stresses;

Cf is the phase angle between stresses and strains. After amplifying the signal from the deformation sensor I with the first amplifier 2 and passing the amplified signal through the frequency multiplier 6, an electrical signal is supplied to the power supply circuit of the mechanical voltage sensor 3

and, K, e.sin

(X + l) cot.

where K is the gain of the amplifier 2,

The output signal from the sensor 3 mechanical stresses, amplified by the second amplifier 4, is proportional to the product and the transfer coefficient of the sensor 3, and can be expressed by the equation

and, Kj „, -3 ± t1 (K + lbt.Gsin (cot + cf),

The signal from the output of amplifier 4 is fed to the inputs of blocks 7 and 8 of multiplication, in which frequency multiplied with the output signals of multiplier 5, which are equal at the first output

and Kcot5

and on the second exit

and K Ep, sin K tot,

where K, Cd is the transfer coefficient of the multiplier 5 h 1 stota.

The output of block 7 multiplies the voltage

and, Kcjt.sin (K + Owt-G x. sin {cot + S.

Ha the output of block 8 multiplies the voltage

Ub, cos Ktot. sin (K + l) aJt x, X b „sin (cot + S).

b (cJt + cf),

where C is the amplitude of mechanical stresses;

Cf is the phase angle between stresses and strains. After amplifying the signal from the deformation sensor I with the first amplifier 2 and passing the amplified signal through the frequency multiplier 6, an electrical signal is supplied to the power supply circuit of the mechanical voltage sensor 3

20

and, K, e.sin

(X + l) cot.

where K is the gain of the amplifier 2,

The output signal from the sensor 3 mechanical stresses, amplified by the second amplifier 4, is proportional to the product and the transfer coefficient of the sensor 3, and can be expressed by the equation

and, Kj „, -3 ± t1 (K + lbt.Gsin (cot + cf),

The signal from the output of amplifier 4 is fed to the inputs of blocks 7 and 8 of multiplication, in which frequency multiplied with the output signals of multiplier 5, which are equal at the first output

and Kcot5

and on the second exit

and K Ep, sin K tot,

where K, Cd is the transfer coefficient of the multiplier 5 h 1 stota.

The output of block 7 multiplies the voltage

and, Kcjt.sin (K + Owt-G x. sin {cot + S.

Ha the output of block 8 multiplies the voltage

Ub, cos Ktot. sin (K + l) aJt x, X b „sin (cot + S).

F u r u tion,

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enters the measure

the voltage circuit of the potentiometer 9, and the signal Ug - into the power supply circuit of the bridge measuring circuit of the potentiometer 9. The voltage on the output of the measuring diagonal of the bridge circuit of potentiometer 9

L g

where n is the displacement of the slider of the reichord of the measuring bridge circuit 10 from the zero position.

The input of the null organ 1I of potentiometer 9 is the difference of the voltage

Scientific research institute

uu

wed

 Us - UT

2

The electronic potentiometer motor 12 is an integrating element and moves the slide rail.

Thus, the condition uUjp b is satisfied. After the last equality is transformed,

l KS

Relative energy loss 27 sincp,

where U W is the energy dispersed in the material;

W - energy stored in the material in one cycle of variable load. Taking into account the latter condition, the energy loss through slider displacement. rheochords are expressed by the equation

TO,

 21G Jil 7 Kb

1 +

Jk K.

Introducing frequency multipliers K and K + 1 times using the sin and cos components at the outputs of the multiplier 5 frequencies K times improves the accuracy of measurements and extends the frequency bandwidth

, - "" by eliminating the phase shifter of low-frequency signals.

VNIIPI Order 608/46

Random polygons pr-tyo, Uzhgorod, st. Project, 4

2952094

It should be noted that the proposed device retains its metrological characteristics even if the shape of the signals of mechanical stresses is distorted and contains higher harmonics.

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Claims (1)

Invention Formula A device for determining the energy dissipated in a material in one variable load cycle, comprising a strain sensor, a first amplifier whose input is connected to a strain sensor, a mechanical stress sensor, a second amplifier whose input is connected to a mechanical stress sensor output, an electronic potentiometer measuring bridge circuit, a zero-body, one input of which is connected to one output of the signal diagonal of the bridge circuit, and an executive motor, whose input is connected to the output of the zero-body, and the shaft Connected with a bridge slider, in order to improve the accuracy and expansion of the frequency range, it is equipped with a frequency multiplier B K + 1, the input of which is connected to the output of the first amplifier, and the output is connected to the power supply circuit of the mechanical voltage sensor, frequency multiplier K times with two outputs, the voltage on which is shifted by 90 relative to each other, and its input is connected to the output of the first amplifier, the first multiplication unit, the first input of which is connected to the output of the second amplifier, the second the course is with the first output of the frequency multiplier K times, and the output is connected by one output to the second input zero-; organ, and the second to the second output of the bridge diagonal signal, the second multiplication unit, the first input to which is connected to the output of the second amplifier , the second input is with the second output of the frequency multiplier K times, and the output is with the diagonal power of the bridge circuit. Circulation 678 Subscription