SU1388512A1 - Apparatus for monitoring the degree of compacting of material - Google Patents

Abstract

The invention relates to vibration measuring technology, can be used in construction to measure the degree of compaction of soils and other materials during the compaction process, and improves the accuracy of controlling the degree of compaction of materials. The device contains a vibrator 1, located on the vibrating body of the machine, the measuring unit 2, the indicator 3, the block 4 registration. The measuring unit 2 consists of a half-wave separation unit 5, a first integrator 6, a second integrator 7, a ratio measurement unit 8 and a switch 9. The vibrator includes a piezo accelerometer connected in series, a matching amplifier, a low-pass filter and an integrator. One variant of the half-wave separation unit 5 comprises a Schmitt trigger, a first key, an inverter, and a second key. Another option block 5 contains the first key, connected in series with the inverting follower and the second key. The ratio measurement unit 8 comprises an analog voltage divider and a storage unit. Switch 9 has a Schmitt trigger, a counting trigger, an inverter, three AND circuits and a driver. 3 hp f-ly, 7 ill. cl

Description

co oo 00

JV Yu

(pLiai

The invention relates to a vibration measuring technique, in particular, to a technique of continuous quality control of performance of work, and can be used in construction to measure the degree of compaction of soils and other materials in the process of their compaction.

The purpose of the invention is to improve the accuracy of controlling the degree of compaction of the material.

FIG. 1 is a functional diagram of a device for controlling the degree of compaction of a material; in fig. 2 - functional diagram of vibration transducer; in fig. 3 and 4 are functional diagrams of the half-wave separation unit; in fig. 5 is a functional diagram of a ratio measurement unit; in fig. 6 - switchboard functional diagram; in fig. 7 - timing diagrams for the operation of the device.

The device for controlling the degree of compaction of the material (Fig. 1) contains a vibration transducer 1 located on a vibrating machine organ (not shown), a measuring unit 2, an indicator 3, a recording unit 4. The measuring unit 2 consists of a half-wave separation unit 5, a first integrator 6, a second integrator 7, a ratio measurement unit 8 and a switch 9. The input of the half-wave separation unit 5 is connected to the output of the vibrator 1, and its corresponding outputs are connected to the input of the first bis integrator input the second integrator 7. The outputs of these blocks are connected to the corresponding inputs of block 8, the output of which is connected to the indicator 3. The input of the switch 9 is connected to the output of the vibrator 1, its outputs are connected to the corresponding control m inputs of half separation unit 5, the switch 9 outputs connected respectively to the control inputs of the first integrator and the second integrator 6, 7, moreover, one of the outputs of the switch 9 is connected to the control input of the measurement unit 8 ratio. Unit 4 registration is connected to the output of the vibrator 1 and to the output of the measuring unit 2.

Vibrating transducer 1 (Fig. 2) contains a piezo-X-ray meter 10 connected in series, a matching amplifier 11, a low-pass filter 12 and an integrator 13. The output of the integrator 13 is connected to the output of the vibrating transducer 1.

One of the options for block 5 division

ten

0

35

40

/ cm -)

keys to the output of the half-wave separation unit 5. In addition, the control inputs of the first 15 and second 16 keys are connected to the corresponding control inputs of the half-wave separation unit 5.

Another variant of the half-wave separation unit 5 (FIG. 4) comprises a first key 18, an inverting repeater 19 and a second key 20 connected in series. The input of the first key 18 and the input of the inverting repeater 19 are connected to the input of the half-wave separation unit 5, and the outputs of the first 18 and the second 20 keys are connected respectively to the outputs of the half-wave separation unit 5. In addition, the control inputs of the first 18 and second keys 20 are connected to the corresponding control inputs of the half-wave separation unit 5.

The ratio measurement unit 8 (Fig. 5) contains a serially connected analog voltage divider 21 and a storage unit 22. The inputs of the analog voltage divider 21 are connected to the corresponding inputs of the block 8, the output of the storage unit 22 is connected to the output of the block 8, and the control The input of the backup device 22 is connected to the control input of the ratio measurement unit 8.

The switch 9 (Fig. 6) contains a Schmitt trigger 23, the input connected to the input of block 9, the counting trigger 24 inverter 25, the inputs of which are connected to the input of the Schmitt trigger 23, circuits And 26, 27, 28, driver 29 short pulses. The inputs cxeiyibi And 26 are connected to the Schmitt trigger 23 output and to the first output of the counting trigger 24, the inputs of the AND circuit 27 are connected to the output of the inverter 25 and to the first output of the counting trigger 24, and the inputs of the And 28 circuit are connected to the second output of the counting trigger 24 and the output of the inverter 25, the inputs of the imager 29 short pulses connected to the second output of the counting trigger 24 and to the output of the Schmitt trigger 23. The outputs of the circuits And 26 and 27 are connected respectively to the outputs of block 9, the output of the circuit And 28 is connected to the outputs of block 9, the output of the imager 29 short pulses by Connected to the output of block 9.

FIG. 7 shows the voltage diagrams at the outputs and inputs of the circuit elements of the device with the first variant of the half-wave separation unit, where: diagram

half wave (Fig. 3) contains a Schmitt trigger trigger 30 - the signal at the output of the filter 12 is low

14, the input of which is connected to the input of the block of frequencies; chart 31 - output signal

5 half-wave separation, first key 15, vibration converter 1; Diagram 32 -

the input is connected to the output of the trigger signal at the output of the Schmitt trigger 14;

Schmitt 14, serially connected diagram 33 is a signal at the output of block 9,

the inverter 16 and the second key 17. In this diagram, 34 is a signal at the output of block 9;

the input of the inverter 16 is connected to the output of the trigger-55 diagram 35 - the signal at the output of block 9; Hera Schmitt 14, the output of the first key 15 is connected to the output of the half-wave separation unit 5, and the output of which key 17 subdiagram 36 is the output signal of the block 9; diagram 37 shows the signal at the output of the first integrator 6; diagram 38 - signal on

0

0

five

0

with -)

keys to the output of the half-wave separation unit 5. In addition, the control inputs of the first 15 and second 16 keys are connected to the corresponding control inputs of the half-wave separation unit 5.

Another variant of the half-wave separation unit 5 (FIG. 4) comprises a first key 18, an inverting repeater 19 and a second key 20 connected in series. The input of the first key 18 and the input of the inverting repeater 19 are connected to the input of the half-wave separation unit 5, and the outputs of the first 18 and the second 20 keys are connected respectively to the outputs of the half-wave separation unit 5. In addition, the control inputs of the first 18 and second keys 20 are connected to the corresponding control inputs of the half-wave separation unit 5.

The ratio measurement unit 8 (Fig. 5) contains a serially connected analog voltage divider 21 and a storage unit 22. The inputs of the analog voltage divider 21 are connected to the corresponding inputs of the block 8, the output of the storage unit 22 is connected to the output of the block 8, and the control The input of the backup device 22 is connected to the control input of the ratio measurement unit 8.

The switch 9 (Fig. 6) contains a Schmitt trigger 23, the input connected to the input of block 9, the counting trigger 24 inverter 25, the inputs of which are connected to the input of the Schmitt trigger 23, circuits And 26, 27, 28, driver 29 short pulses. The inputs cxeiyibi And 26 are connected to the Schmitt trigger 23 output and to the first output of the counting trigger 24, the inputs of the AND circuit 27 are connected to the output of the inverter 25 and to the first output of the counting trigger 24, and the inputs of the And 28 circuit are connected to the second output of the counting trigger 24 and the output of the inverter 25, the inputs of the imager 29 short pulses connected to the second output of the counting trigger 24 and to the output of the Schmitt trigger 23. The outputs of the circuits And 26 and 27 are connected respectively to the outputs of block 9, the output of the circuit And 28 is connected to the outputs of block 9, the output of the imager 29 short pulses by Connected to the output of block 9.

FIG. 7 shows the voltage diagrams at the outputs and inputs of the circuit elements of the device with the first variant of the half-wave separation unit, where: diagram

chart 35 - the signal at the output of block 9;

chart 36 - the signal at the output of block 9; diagram 37 shows the signal at the output of the first integrator 6; diagram 38 - signal on

the output of the second integrator 7; diagram 39 - signal at the output of the analog voltage divider 2; diagram 40 is the signal at the output of the storage unit 22.

In the diagrams, the instants of time ti, ts, te, tio correspond to the beginning of the next measurement process during the first zero crossing with increasing voltage at the output of the vibrator 1, the times t2, t to the first zero crossing when the voltage drops at the output of the vibration converter 1, times ta. is is the second zero crossing with increasing voltage at the output of the vibrator 1, the instants of time t4, tg. the end of the next measurement process during the second zero crossing when the voltage drops at the output of the vibrating transducer 1. In this case, the times ti-ts correspond to the measurement process with a small degree of compaction of the material, and the time moments tio-tio correspond to the measurement process with a large degree of compaction material.

The device works as follows.

The vibrations are vibrated; its organs are perceived by the vibration transducer 1 (Fig. 1) and are converted by it into an electrical voltage proportional to the vibration velocity V of the vibrating organ (Diagram 31, Fig. 7). The oscillation of the vibrating organ from the sinusoidal form is due to the fact that the vibrational machine interacts with the soil half-space. In this case, the vibrating organ is detached from the ground surface, and the residence time of the vibrating organ in the air exceeds the half-period of oscillations. From the output of the vibration transducer 1, the voltage proportional to the vibration velocity V of the vibrating organ oscillations is fed to the input of the separation unit 5 and to the input of the recording unit 4. In block 5 of the half-wave separation, the positive and negative half-waves of the input signal are separated and positive half-waves are output from output 11 to the input of the first integrator 6 and negative half-waves from output 12 to the input of the second integrator 7. In addition, it converts the input signal to the output signal. coal pulses with the same frequency (figure 32). The first 6 and second 7 integrators integrate the incoming signals and memorize the result of the integration. Straight coal pulses, the duration of which is equal to the duration of the positive and negative half-waves of the vibration velocity V, are converted in blocks 6 and 7 into proportional stresses of these durations (diagrams 37 — time moments ti-12 and 38 — time points). In the case of a variant of block 5, the half-wave separation is positive and the negative half-wave (diagrams 41 and 42) is converted into voltages proportional to the positive square

Noh half-wave vibration speed U 5:, (t) dt

t,

(Diagram 43 — time instants ti-ta) and the area of the negative half-wave velocity to Ui,. (t) dt (chart 44-

cops of time t2-1h). After the conversion process is completed, the integration results are memorized (diagram 37, moment of time to, diagram 39 — moment of time h), diagram 43 — moment of time ta, diagram 44 — moment of time ts) and fed to the corresponding inputs of block 8. In block 8, the ratio measurement is dividing the voltage from the output of block 7 to the voltage from the output of block 6. Next, the voltage generated by the division result (diagram 39 - time ts) is memorized and fed to the input of indicator 3 (diagram 40 - time ts). After the appearance of pulses at the outputs of block 9 (diagram 36 - time instant t,)), the information is erased in the first 6 and second 7 integrators and the whole measurement process is repeated again.

When the density of the soil is low, the soil half-space has little effect on the vibration of the vibrating organ of the vibrator; therefore, the duration (ta-ti) of the positive half-wave velocity V (diagram 31, times ti-to) is almost equal to the duration (ta-to), and therefore and the voltages Ui and Do (diagram 37 — moment of time, ts, diagram 38 — moment of time ta) at the outputs of the first and second 7 integrators are almost equal. This means that the ratio of these voltages U2 / U: will be small and the indicator 3 reads low (figure 40 - time point ta). With a high density of soil, it increases the reaction force to periodic dynamic loads from a vibrating organ, therefore the ground will have a greater effect on the oscillation of the vibrating organ, changing the shape of its oscillations. This leads to the fact that the duration () of the positive half-wave of the vibration velocity V (diagram 31 - time instants te-tio) differs significantly from the duration (tg-ty) of the negative half-wave of the vibration velocity V, therefore the ratio by 1 times the U4 / Us will be ( Chart 39 - time point ts) and indicator 3 reads higher (Chart 40 - time point t).

Indicator 3 readings do not depend on the frequency of the vibration of the working body of the vibrating machine. The independence of the readings from the frequency is seen from the following. The signal generated by the conversion of mechanical vibrations of a vibrating organ into electrical voltage using a piezo accelerometer 10 (Fig. 2) contained in a vibrator 1 (Fig. 1), (chart 30, Fig. 7) can be represented as a series of harmonic components (p yes Fourier)

U. (t) C, + r | jQ | -Cos K 2jif-t + argQ), (1)

where T (1z-t2) + (t2-ti) is the period of the signal oscillation and „(1) with frequency f; 10 TO (ts-t2) -f (tz-ti) is the oscillation period of the signal U «(t) with the frequency fo. Then,,,

T (t3-t2) + (t2-ti) i- T „

n

(five)

where (1) is the signal on the output of the piezo accelerometer 10;

Co - permanent member; Ck - amplitude of the K-th harmonic

Components; , 1,2, ..., harmonic component number - 15

you;

f is the signal frequency; argCj, is the phase of the harmonic component. This signal passes through the integral-Q. The ratio of the half-wave durations is equal to 13, also contained in the vibrator 1, which is described by the expression-ts-iz

by:

 (t3-t2) + (t2-tl)

P

  (t3-t2) + (t2-t,).

(t3-t2)

n (t3-t2)

t2-t, 4- (t2-t,) n (t2-t,)

U4t) KI U, (t) dt + Uo,

(2)

the output is an integratode (L1) -signal pa 13;

K. —nr — gain factor of the integrator 13;

and „- the initial condition of integration.

For voltages varying according to the sinusoidal law U (t) UCoscot, the formula for the output voltage of the integrator 13 will be

) - j (5 UCoscot dt-f Uo (3)

 2nfRC

.sinwt-l- Uo,

where is the circular frequency, c.

Expression (3) shows that the amplitude of the output signal is inversely proportional to the frequency, but this only leads to the fact that the harmonic components at the output of the integrator 13 will have different amplitudes, decreasing as the harmonic number increases. If the signal Uo (t) has a certain amplitude and shape (diagram 30) at a frequency fo, then the signal at the output of the integrator 13 will look like that shown in diagram 32. When the frequency of the signal Ua (t) changes n times at the same amplitude and form

45

50

The vibrations of the vibrating organ are sensed by the piezo accelerometer 11 and are converted by it into an electrical voltage proportional to the vibration acceleration of the vibrating organ. Further, this voltage passes through a matching amplifier 11 with a high-impedance input designed to eliminate the influence of subsequent stages of the device on the operation of the piezo accelerometer 10, and through a low-pass filter 12 in which parasitic high-frequency vibration components are suppressed. From the output of the low-pass filter 12, the signal is fed to the integrator 13, where an electrical voltage proportional to the vibration acceleration and is converted to a voltage proportional to the vibration velocity V of the worker.

i

The organ of the vibrator Uu (t) KS Uo (t) dt (Diagram 31, Fig. 7). From the output of the integrator 13, the signal goes to the output of the vibrator 1.

The work unit 5 division half-waves

signal, the output of the integrator 13 on Vits 55 according to the functional diagram (Fig. 3) consists

the signal with the frequency f nfo and the form is the same as in diagram 31, but with an amplitude that is n times smaller.

in the following.

From the output of the vibrator 1, the voltage С „(1) is fed to the trigger input

Since the waveform at the output of the integrator 13 does not change as the frequency changes, the ratio of the durations of the positive and negative half-waves will also be frequency independent.

g ±

If nfo, or

t t t

1- - io,

(four)

where T (1z-t2) + (t2-ti) is the period of the signal oscillation and „(1) with frequency f; TO (ts-t2) -f (tz-ti) is the oscillation period of the signal U «(t) with the frequency fo. Then,,,

T (t3-t2) + (t2-ti) i- T „

n

(five)

 (t3-t2) + (t2-tl)

P

  (t3-t2) + (t2-t,).

half wave

(t3-t2)

n (t3-t2)

t2-t, 4- (t2-t,) n (t2-t,)

(6)

0

five

0

five

0

So, in the device, when measuring the ratio of the durations of the half-waves of the vibration velocity V, the indicator readings do not depend on the frequency of the vibration of the vibrator working element.

The operation of the vibrator 1 according to the functional diagram (Fig. 2) is as follows.

The vibrations of the vibrating organ are sensed by the piezo accelerometer 11 and are converted by it into an electrical voltage proportional to the vibration acceleration of the vibrating organ. Further, this voltage passes through a matching amplifier 11 with a high-impedance input designed to eliminate the influence of subsequent stages of the device on the operation of the piezo accelerometer 10, and through a low-pass filter 12 in which parasitic high-frequency vibration components are suppressed. From the output of the low-pass filter 12, the signal is fed to the integrator 13, where an electrical voltage proportional to the vibration acceleration and is converted to a voltage proportional to the vibration velocity V of the worker.

i

The organ of the vibrator Uu (t) KS Uo (t) dt (Diagram 31, Fig. 7). From the output of the integrator 13, the signal goes to the output of the vibrator 1.

The work unit 5 division half-waves

5 according to the functional diagram (Fig. 3) consists

in the following.

From the output of the vibrator 1, the voltage С „(1) is fed to the trigger input

Schmitt 14, which converts this voltage into rectangular pulses with the same frequency (Figure 34). Next, these pulses arrive at the input of the first key 15 and through the inverter 16 to the input of the second key 17. Block 9 (Fig. 1) generates such signals at its outputs (diagram 33 - time ti, diagrams 34 - time t2) so that one once in two oscillation periods, the pulses through the keys 15 and 16 passed to the input of the first 6 and second 7 integrators respectively.

The operation of the half-wave separation unit 5 (2nd version) according to the functional diagram (Fig. 6) is as follows.

From the output of the vibrator 1, the voltage U (, (t) is fed to the input of the first key 18 and to the input of the inverting repeater 19. From the output of the inverting repeater 19, the signal, opposite to the input, is fed to the input of the second key 20. The control unit 9 generates such signals at their outputs, once for two periods of oscillations a positive half-wave passes through the first key 18 to the input of the first integrator 6 (diagram 41 - time instant ti), and a negative half-wave passes through the second key 20 to the input of the second integrator 7 (diagram 42 - time t2).

The operation of unit 8 (Fig. 5) is as follows.

From the output of integrators 6 and 7, the signals Ui and U2 (diagrams 37 and 38 are times t2-i) or Us and Ue (diagrams 43 and 44 are times t2- (4) are fed to the inputs of the analog voltage divider 21, in which The voltage from the output of the integrator 7 is divided by the voltage from the output of the integrator 6. Next, the voltage, which is the result of the division (diagram 39 - time ts) or diagram 45 - time, is fed to the input of the storage device 33, where after of the control pulse from the output of switch 9 (diagram 35 - time instant ts) ominaets and fed to the output section 8.

The operation of the switch 9 (Fig. 6) is as follows.

From the output of the vibrator 1, the signal Ut. (T) is fed to the input of a Schmitt trigger 23. In it, it is converted into square pulses of the same frequency and fed to the input of inverter 25 and to the input of counting trigger 24, in which the frequency of these pulses is divided by 2. After that, the pulses from the output of the Schmitt trigger 23, from the output of the inverter 25 and from the outputs of the counting trigger 24, the signal of the second output of which is antiphase relative to the signal at its first output, are fed to the corresponding inputs of the circuits And 26, 27, 28 and the former 29 short pulses. As a result, the outputs of the circuits And 26, 27, 28

0

Q 5

0

0

five

0

five

the corresponding pulses appear (diagram 33 - moment of time ti, diagram 34 - moment of time t2, diagram 36 - moment of time (4). In pulse shaper 29 a pulse is formed (diagram 35 - moment of time 1h) to enable recording in the memory device 22 is the result. and dividing up to the moment of resetting information in integrators 6 and 7 pulses from the outputs of block 9 (diagram 36 is the time instant t4).

In addition to a piezo accelerometer with a built-in matching amplifier and integrator, an inductive transducer can be used as a vibration transducer, the output value of which is proportional to the vibration velocity. A portable magnetograph in the recording mode with frequency modulation (FM mode) is used as the recording equipment, but in addition to it, any other magnetograph or high-speed self-searching device can be used.

The device operates in the frequency range of vibrations from 5 to 100 Hz and can be used to continuously monitor the degree of compaction of the material with installation on various types of vibratory rollers, which is caused by the lack of dependence of the indicator readings on the frequency of vibration of the vibrating organ.

Claims (4)

1. A device for controlling the degree of compaction of a material, containing a series-connected vibration transducer, a measuring unit, an indicator and a recording unit, characterized in that, in order to improve the accuracy of control, the measuring unit consists of a half-wave separation unit, two integrators, a ratio measurement unit and a switch the first input of the half-wave separation unit and the input of the switch are combined and are the input of the measuring unit; the first and second outputs of the half-wave separation unit are connected to the first inputs The integrators whose second inputs are connected to the first and second outputs of the switch, the third output of which is connected to the first input of the ratio measurement unit, the second and third inputs of which are connected to the integrator outputs, the fourth and fifth outputs of the switch are connected to the second and third inputs of the half-wave separation unit, The output of the ratio measuring unit is the output of the measuring unit and is connected to the first input of the recording unit, the second input of which is connected to the output of the vibrating transducer. 2. A device according to claim I. characterized in that the half-wave separation unit is designed as a Schmidt trigger, an inverter and two keys, the Schmidt trigger input being the first input of the half-wave separation unit, the Schmidt trigger output being connected to one input of the first key and through an inverter with one input of the second key, the other inputs of the keys are the second and third inputs of the half-wave separation unit, and the outputs of the keys are the outputs of the half-wave separation unit. 3. A device according to claim 1, characterized in that the half-wave separation unit is designed as an inverting repeater and two keys, one input of the first key and the input of the inverting repeater combined and being the first input of the half-wave separation unit, the output of the inverting FIG. 2 Phage.4 the repeater is connected to one input of the second key, the other inputs of the keys are the second and third inputs of the half-wave separation unit, and the outputs of the keys are the outputs of the half-wave separation unit. 4. The device according to claim 1, wherein the ratio measurement unit is configured as a series-connected analog divider and a memory device, the two inputs of the analog divider being two inputs of the ratio measuring unit, one of the memory inputs is the third input of the measurement unit ratio, and the output of the memory device is the output of the ratio measurement unit. Ph.5 FIG. AT and 50 31 32 3J 34 35 5 37 53 33 : fi5.7