RU1827569C - Stand for rupture tests of rotary parts - Google Patents

Abstract

The invention relates to a test technique. The purpose of the invention is to increase accuracy by eliminating the imbalance during rotation of the test piece. The test bench for rotating parts for tensile testing includes a vacuum accelerating chamber 1, an electric rotary actuator 4, a rotational speed sensor 5, a rotational control circuit 6 connected to a logic unit 7, a servo-transducer 8 and a measuring amplifier 9 connected in series to a crack growth sensor 12 , a rotation speed recording unit 13 of the test piece 2 and a speed survey means 14 connected to the output of the rotation speed sensor 5 and the output of the rotation control circuit 6, and the destruction sensor 15 is connected connected to the inputs of the speed survey means 14 and the logic unit 7, the output of which is connected to the output of the rotation speed recording unit 13. The bench comprises a frequency multiplier 17 connected in series, a first harmonic extraction unit 10, and an automatic balancing device 11. The frequency multiplier 17 is connected to the output of the rotation speed sensor 5 and to the input of the rotation speed recording unit 13 of the part 2. The first harmonic extraction unit 10 is connected to the output of the measuring amplifier 9 and the devices 11 for automatic balancing, which is connected to the outputs of the logic unit 7, the multiplier frequency 17 and rotation control circuit 6. 1 ill.

Description

The invention relates to testing equipment, in particular to devices for tensile testing of parts such as bodies of revolution, and can be used to determine fracture and cracking parameters by centrifugal force.

The purpose of the invention is to increase the accuracy of testing by eliminating the imbalance during rotation of the test piece.

The drawing shows a diagram of a bench for testing rotating parts for breaking.

The bench contains a vacuum accelerating chamber 1, designed to accommodate the test piece 2 mounted on the damper supports 3, and mechanically connected to the electric drive 4

yo vj eat oh

with a rotation speed sensor 5, a control circuit b, a first output Connected to the input of the electric drive 4, a logic unit 7, a vibration sensor 8 connected in series, a measuring amplifier 9, a first harmonic extraction unit 10 and an automatic balancing device 11, sequentially connected to the damper support 3 the connected crack sensor 12 mounted on the rotating part 2, the registration unit 13 and speed survey means 14, the destruction sensor 15 installed in the vacuum distillation chamber 1 associated with it the destruction recorder 1G and the frequency multiplier 17, the first output of which is connected to the control input of the first harmonic extraction unit 10 and the second input of the automatic balancing device 11, the input of the frequency multiplier 17 is connected to the first output of the rotation speed sensor 5, the second output of which is connected to the second input means 14 high-speed shooting, the input connected to the output of the recorder 16 destruction, the second output of the control circuit b is connected to the first input of the logical Block 7, the second input connected to the second output registration lock 13, the second input of which is connected to the second output of the frequency multiplier 17, the third input of the logic unit 7 is connected to the output of the destruction recorder 16, and the first and second outputs are connected respectively to the third and second inputs of the control circuit b, the first input connected to the second input of the means 14, and the fourth output connected to the output of the first harmonic extraction unit 10, the third output of the control circuit 6 is connected to the fourth input of the logic unit 7, the third output of which is connected to the control the device 11 for automatic balancing, the control circuit contains a serially connected master 18 operational amplifier 19, an integrator 20 and a power converter 21, the output of which is the first output of the circuit, the first and second keys 22 and 23, the first and second comparators 24 and 25, an adjustable limiter 26 and serially connected unipolar amplifier 27 and an adder 28, the output of which is connected to the control input of the adjustable limiter 26, the first output connected to the first input of the operating a amplifier 19, the second input of which represents the first input of the circuit, the first input of a unipolar amplifier 27 is connected to the first inputs of the first and second comparators 24 and 25, the outputs of which are the second and third outputs of the circuit, the second output of the master 18 is connected to the second input adder 28,

the third and fourth outputs are connected to the second inputs of the first and second comparators 24 and 25, the fourth output of the master 18 is also connected to the second input of the unipolar amplifier 27, the first input of which is the fourth input of the circuit, the second output of the adjustable limiter 26 is connected to the input of the integrator 20 and the first output of the second key 23, the second output of which is connected to the output of integrator 20, and the control input is the second input of the circuit, the third input of which is the control input of the first key 22. Logically The sky block contains the logical element And 29,

0 the first, second and third logical elements AND-NOT 30, 31. 32 and the RS-flip-flop 33, whose R-input is the installation in progress, and the S-input is the second block input, the direct output of the RS-flip-flop 33 connected

5 with the first input of the first logic element 30, the output of which is the first output of the block, and the second input is connected to the first input of the second logical element AND-NOT 31, inverse output

0 RS-trigger 33 is connected to the second input of the second logic element l / 1-HE 31, the first input of which is the first output of the block, and the output is connected to the first input of the third logic element 5 AND-NOT 32, the output of which is the second the output of the block, and the second input is the third input of the block, the first input of the first logical element N-NOT 30 is connected to the first input

0 of AND gate 29, the second input of which is the fourth input of the block, and the output is its third output. The registration unit 13 comprises serially connected master 34 and

5, a first comparator 35, connected in series to the crack length measuring unit 36, the input of which is the first input of the registration unit 13, the second comparator 37 and the speed meter 38

0 rotation, the first and second inputs of which are respectively the first output and the second input of the register-TDI block 13, the second output of the setter 34 is connected to the second input of the second Comparator 37,

5 by a first input connected to a second input of a first comparator 35, the output of which is the second output of the registration unit 13.

Means for high-speed shooting 14 comprise series-connected IK-trigrep 39, a synchronization unit 40, and a movie camera 41, the 1-input of the 1K-trigger 39 being the first input of the apparatus. The K-input is its third input, and the second input of the synchronization unit 40 is the second input of the speed survey means 14.

The test bench for rotating parts for breaking works as follows.

A test device rotating with a part 2, for example, a turbomachine disk with an artificial stress concentrator, is mounted on damping supports 3 inside a vacuum accelerating chamber 1, in which the required level of vauum is maintained. By means of an autonomous electric drive 4, the part 2 is linearly accelerated with the operating rate OG determined by the signal UG increasing linearly with the rate Uo from the first output of the control circuit 6. The analog signal Us2, generated in accordance with the current speed of the electric drive 4 at the second output of the rotation speed sensor 5, acts on the first input of the control circuit 6, providing a level of speed limitation in accordance with the structural strength of the electric motor and the machine line.

The control of the increasing rotation speed of the test part 2 is carried out in the recording unit 13 by the frequency signal Ui co coming to its second input, the second output of the frequency multiplier 17, the multiplication factor Ki of which at the second output is set depending on the transmission coefficient of the rotational speed sensor 5 Kg output and reduction coefficient of the machine line accelerator.

The recording unit 13, in addition, by the signal U12 from the crack sensor 12, which is, for example, a system of strain gauges or conductors, monitors the occurrence of stresses. Until the signal Ui2 reaches a predetermined level Ucrp corresponding to the voltage in the hub zone at the time of cracking, the logic unit signal is applied to the i-input of the IK-trigger 39, which is previously set to zero, from the first output of the registration unit 13, without influencing him. At the second output of the registration unit 13, a single signal also appears at this time and acts on the second input of the logic unit 7, the third input of which until the end of the test is affected by the signal of the logical unit generated by the destruction recorder 16.

If the operating frequency range of the tested part 2 contains resonance regions 5, it is advisable to go through them at an increased rate, depending on the level of the vibration signal Us from the vibration sensor 8, which is set by the measuring amplifier 9 and fed to the input of the block 10

0 the allocation of the first harmonic, containing, for example, a resonant amplifier and the following filter, with which the first harmonic of the frequency of the reference signal is synchronized, phase locked

5 with the frequency of the signal from the first output of the frequency multiplier 17, the multiplication factor Kp1 of which at the first output is set depending on the transmission coefficient Ks1 of the speed sensor 5 for the digital output and the parameters of the first harmonic extraction unit 10.

If during acceleration of the test part 2, the signal Uy from the block 10 of the selection of the first

5, the harmonic input to the fourth input of the control circuit 6 does not exceed that set in the last level at the third output of the control circuit — a zero level signal is formed and acts on

0 the fourth input of the logical unit 7t does not change its initial state, characterized by the establishment of a logical unit signal at its first output and a logical zero signal at its second

5 output acting on the third and second inputs of the control circuit 6, contributing to the acceleration of the electric drive 4 with part 2 according to a linear law with the operating rate of OQ. At the same time, the logic signal

0 zero of the third output of the logic unit 7 acts on the control input of the device 11 for automatic balancing, keeping it in the off state.

5. If the changing signal Uio reaches or exceeds the set level Uoi at the third output of the control circuit 6, a logic unit signal will appear that does not change the initial state of logic unit 7. However, from now on, the drive 4 accelerates with an increase within the operating range values of the rate, which is determined by the slew rate of the output signal of circuit 6

5 control depending on the signal level Uyu Accelerated passage of the electric drive 4 zones of rotational speeds with a high level of vibration eliminates the likelihood of premature damage to the test part 2

If for some reason not related to the presence of resonance zones established during operation, as well as the occurrence and development of cracks on the part. 2 (for example, when bearings are damaged, unbalanced, etc.), when the drive 4 is accelerated, the changing vibration signal Uio will reach or exceed the level Uo2- set in the control circuit b at the second and third outputs of the last voltage and operate the first and fourth inputs of logical unit 7 are logical unit signals, causing the appearance of logical unit signals at its first and second outputs, affecting the third and second inputs of control circuit b, which turns off the electric drive 4 and brakes it with the test my item 2 is in free-run mode until it stops. After that, control of the machine line, balancing of part 2 and other operations are carried out to reduce the level of vibration at operational speeds of rotation, providing high reliability and reliability of the tests. At the moment of the appearance of cracks on the part 2, which accelerates at an operating linear rate in the region of high rotation speeds, a logical zero signal is generated at the second output of the registration unit 13 when the signal U12 from the sensor 12 of the crack 12 generates a signal and acts on the second input of the logical unit 7 , Until the signal level Uio exceeds the set value Uoi, from the first and second outputs of the logic unit 7 to the third and second inputs of the control circuit 6, the signals of logical units, respectively, and zero, in the presence of which the electric drive 4 with part 2 continues to accelerate with a forward pace of about, ensuring high test accuracy, eliminating the possibility of premature failure of part 2.

As soon as a result of the further development of cracks at the moment preceding failure, on the test piece 2, due to anisotropic plastic deformation, the forks are unevenly drawn and the imbalance associated with it and the Uio signal will exceed the set Uoi level. at the third output of the V-control circuit b, the signal is a logical unit, which causes the appearance of a single signal at the third output of the logical unit 7, which turns on the device 11 for

automatic balancing, providing balancing of the part 2 during its rotation by one of the known methods, for example, laser, electroerosive, electro-radiation, electrochemical, wire explosion, etc., which can be performed according to the known structure corresponding to the balancing method being implemented.

The device 11 compares the phases of the signal U from the first harmonic extraction unit 10 and the signal Ui with increasing frequency from the first output of the frequency multiplier 17, performing multiple measurements and eliminating the imbalance at each revolution, reducing vibration to a given level of Uoi and eliminating the possibility of premature destruction of part 2 provides high test accuracy. If, in this case, the June signal can be reduced to a predetermined level Uoi, the acceleration of part 2 occurs at an increased rate within the operational value, depending on the change in the magnitude of the vibrations.

If during the growth and development of cracks on the balanced part vibrations continue to grow and the signal Uio reaches the set emergency value Uo2. a logic unit signal is generated at the second output of the control circuit 6, which acts on the first input of the logic unit 7, causing a logical zero signal at its first output. The latter enters the third input of the control circuit b, which begins to generate a sharply increasing control signal Ue, which ensures that the drive 4 is accelerated at the highest possible rate, which should be at least the frequency until the dynamic amplification coefficient reaches its stationary value, since unbalance of part 2 can serve cause premature fracture of the shaft and destruction of the rotating part 2 on the wall (armor) of the vacuum accelerating chamber 1.

Upon further acceleration of the electric actuator 4, an intensive crack growth occurs on the test part 2, the length of which in the recording unit 13 is continuously compared with the critical value determined by the signal setting UKp.

When the crack on part-2 reaches a predetermined critical length, the recording unit 13 remembers the rotation frequency corresponding to it, information about which continues in the form of a frequency signal Ui7 from the second output of the frequency multiplier -17. At the same time, at the first output of the registration unit 13, I will display a signal (of zero, acting on the K-input of the IK-trigger 39. changing its state to the opposite, in which the signal of the logical unit acts on the synchronization unit 40 of the high-speed shooting means.

The synchronization unit 40 is a common electric drive of the tape drive mechanism and a mirror drum of the movie camera 41, interconnected by an electromagnetic clutch. When the electric drive 4 is accelerated, in accordance with the signal Us of the rotation speed sensor 5 of the spinning of the mirror drum, the angle of rotation of the part 2 is synchronized with the cinema frequency 41 of the movie camera 41.

When a single signal from the IK-trigger 39 arrives at the first input of the synchronization block 40, the electromagnetic clutch is turned on, connecting the tape drive of the movie camera 41, which records the destruction process with a frequency

nth zero signal, including device 11 for automatic balancing.

Block 13 registration works as follows.

Through the second input of the block to the second input

a speed meter 38, which, for example, is a frequency meter with a memory unit, receives a pulse signal, the rising frequency of which is indicated digitally ...

The crack length measuring unit 36, made according to one of the known schemes, receiving information from the sensors through the first input of the device, for example, using a current collector, generates a signal hut proportional to the length of the developing one. cracks during plastic deformation of the part, which enters the input of the first and second comparators 35 and 36. where it is compared with the constant signals 1Y and U342 of the setter 34.

In this case, at the output of the first comparator 35, the signal changes in accordance with the expression

-1

Uiti at Use 1Ы

U35

where pd is the rotation frequency of the test piece 2.

At the moment of destruction of the part 2, its fragments act on the destruction sensor 15, which is, for example, a wire mesh stretched in a vacuum accelerating chamber 1 to which voltage is applied.

When the grid is broken at the output of the voltage recorder 16, a logic zero signal appears, simultaneously acting on the K-input of trigger 39 and the third input of logic block 7. Since then, the IK-trigger 39 returns to its initial zero state, in which its output signal logical zero disables the electromagnetic clutch of the synchronization unit 40, thereby disabling the tape mechanism of the movie camera 41, stopping the shooting. At the same time, the logic unit signal appears at the second output of the logic unit 7 and acts on the second input of the control circuit 6, which turns off the electric drive 4, putting it into coast braking mode until it stops. When at the third output the sum of control 6 of the logic zero signal appears and it is exposed to the fourth input of the logic unit 7, the third output of the latter is formed

About with Uze 11z4

where 1Ы1 is the signal setpoint from the first output of the setter 34, corresponding to the signal Ucip of the sensor 12 at the time of crack breaking on the part 2:

UKI is the output signal of the first comparator 35, corresponding to the level of a logical unit.

At the output of the second comparator 37, the signal changes in accordance with the expression

ШК2 at U36 1Ы2

U3H2

0 at 3:,

where 11z4 is the signal setpoint from the second output of the setter 34, corresponding to the signal of the sensor 12 at the moment the crack reaches a critical length;

 - the output signal of the second comparator 37, corresponding to the level of a logical unit.

At the moment the signal device arrives at the first input, the output of the first comparator 35, which is the second output of the device, produces a logic zero signal.

As soon as the signal at the second input of the device rises to the UKp level. from the output of the second comparator 37 to the first output of the device receives a signal of logical zero, which simultaneously affects the first input of the frequency meter 38

rotation at which the frequency of the signal arriving at this time at its second input through the second input of the device is stored.

The control circuit 6 operates as follows,

The level of the constant signal Uie1 of the task from the setter 18 by comparing it at the input of the operational amplifier T9 with the increasing feedback signal fed to the first input of the circuit limits the maximum rotation speed at which the destruction of part 2 takes place, selected from the condition of the structural strength of the electric drive and the machine lines.

Since when testing during acceleration of the electric drive 4, its rotation frequency cannot reach the limit determined by the reference signal Die1, the output signal of the operational amplifier 19 with a high transmission coefficient in the open state is set to Uig, determined by the setting of the adjustable limiter 26, included in its feedback circuit when the first key 22 is closed during the logical unit signal G. The third input of the circuit controlled by the reference signal Uae from the output of the adder 28, which defined by the formula

U28 U27 + U182.

where U18 is the reference signal from the second output of the setter 18, the level of which determines the acceleration rate of the electric drive 4;

U27 is the output signal of a unipolar amplifier 27 with a transmission coefficient Ku, which varies in accordance with the expression:

U27 4

0. if u u suie.

Ky (Uio-Ui84) ecflHUio Ui84, 40

where U ju is the output signal of the first harmonic extraction unit 10 supplied to the first input of unipolar amplifier 27;

Uie4 Uoi is a constant setpoint signal from the fourth output of master 18, which is fed to the second input of unipolar amplifier 27.

When the actuator 4 is operating outside the resonance frequency region, characterized by a low level of vibration on the tested part 2, corresponding to the condition U u U18, a constant signal Die2 is installed at the output of the operational amplifier 19 and acts on the input of the integrator 20, unblocked by opening the second key 23 when exposure to the second input of the logic zero signal circuit. AT

in this case, at the input of the integrator 20 with a constant integration time T, the signal Uao increases linearly

U2o (t)

1

the

t.

The output signal Ue1 of the control circuit b, which is a signal at the output of the power converter 21 with the transmission coefficient Kp, increases linearly

fifteen

U61 (t) U2o (t) Kn

with pace

U28

Kp

When approaching the electric drive 4 to the operating frequencies, characterized by an increased level of vibration of the tested part 2, as soon as the value Uy exceeds the set level Uie2, a signal appears at the output of the unipolar amplifier 27, increasing the output signal of the operational amplifier 19, which facilitates accelerated

increasing the output signal of the circuit

horse

Ufrt) IKy (Uio-Ute) + .t

35

with pace

„1- {Ky (Uio-u18) + od-t

When a logic zero signal arrives at the third input of the circuit, the first key 22 is opened, and the operational amplifier 19 is put into operation with saturation of the output signal Uig at the level UH. In this case, a ramp signal is generated at the output of the control circuit 6

U61 (t): j: -UH Kp t

with pace

/ - and ". to

O2- K-p

providing accelerated acceleration of the electric drive 4.

If a logical unit signal is supplied to the second input of the circuit, then regardless of the level of the signal supplied to its first input, the second key 23 is closed and

shunts the integrator 20. providing in the absence of the output signal Ue stop the actuator 4.

If, for any reason, the command to turn off the output signal did not pass, then when the electric drive 4 is further accelerated to a speed corresponding to the specified signal setting Uis1 from the setpoint 18, the feedback signal Uoc Us2 is supplied to the first input of the circuit, providing an alternating signal for the output of the operational amplifier 19 and setting the output signal Ue1 to a constant level.

The signal Uic, which changes in accordance with the vibrations on the test piece 2, through the fourth input of the circuit is continuously fed to the first inputs of the first and second comparators 24 and 25, where it is compared with. given levels of Uie3 Uo2 and Uia4 Uoi arriving at their second inputs. The output signals of the first and second comparators 24 and 25 are changed in accordance with the expressions

1)

U25

UK1 with Uy SUo2, 0 with Uy Uo2,

K2 at Uip Uoi. Oh at Uio Uoi,

where UK1 is the output signal of the first comparator 24, corresponding to the level of a logical unit, supplied to the second output of the circuit;

11k2 - the output signal of the second comparator 25, corresponding to the level of the logical unit, supplied to the third output of the circuit.

Logical block 7 operates as follows.

Before starting operation, the RS flip-flop 33 is set to the zero state by applying a pulse to its R input. If a logical zero signal is supplied to the first and fourth inputs of a block, and a logical unit signal is supplied to the second and third inputs, the logical unit 7 is set to its initial state, in which a logical unit signal is generated at its first output, and at the second and third outputs signals of logical zero.

If, when the electric drive approaches the region of resonant frequencies of rotation through the fourth input of the block, the signal of the logical unit acts on the second input of the logical element And 29. The state of the logical block 7 does not change, since at this time the zero input from the logical input And 29 5 outputs of the RS flip-flop 33.

If at the first input of the block when the vibrations increase to the emergency level, a signal of a logical unit arrives and simultaneously affects the second input

0 of the first logical element AND-NOT 30 and to the first input of the second logical element AND-NOT 31. at the output of the latter, a zero signal is generated, fed to the first input of the third logical element AND-NOT

5 32, changing its state, as a result of which a signal of a logical unit appears at the second output of the block.

At the moment the crack is cracked at a low level of vibrations on part 2, the S0 input of the RS-flip-flop 33 acts through the second input of the block through the second input of the block, the signal is a logic zero and changes its state to one. At the same time, a logic zero signal is supplied to the second input of the second logical element I-NOT 31, ensuring that a single signal is kept at its output, which constantly affects the first input of the third logical element I-NOT 32, which generates a logic zero signal, at the second output of the block.

If, after this, the vibrations increase, through the fourth input of the block to the second input of the logical element And 29 a signal of a logical unit will be received and when

5, its first input of a single signal from the direct output of the RS flip-flop 33, it generates a signal of a logical unit appearing at the third output of the block.

The last state of the logical block

0 7 will not change even after the crack reaches a critical length until the vibrations on part 2 increase to the emergency state, as evidenced by the arrival of a logical unit signal

5 through its first input to the second input of the first logical element AND-NOT 30 and the first input of the second logical element AND-NOT 31. Due to the action of its second input, the signal is a logic zero with

0 of the RS flip-flop 33, the single state of the second logical element I-H E 31 will not change, and a logical zero signal is generated at the output of the first logical element I-HE 30, which is fed to the first output of the block.

When part 2, characterized by the arrival of a logic zero signal through the third input of the block to the second input of the third AND-32 logical element, is destroyed. The state of the latter will change, as a result of which the logical unit signal will appear at the second output of the logical unit 7.

Claims (1)

The parameters of cracking and the fracture pattern of the part obtained as a result of the tests make it possible to evaluate its residual bearing capacity in the presence of damage, to determine the kinetic energy of the fragments of the part in solving the problem of their localization. SUMMARY OF THE INVENTION A test bench for rotating parts for tensile testing, comprising a vacuum accelerating chamber for receiving a test part, an electric drive for controlling the rotational speed of the part, a rotational speed sensor, a rotation control circuit, electrically connected to a logic unit, electrically connected to a logic unit, electrically connected to a vibration sensor and measuring amplifier, serially electrically connected crack growth sensor, rotational speed registration unit 5 0 5 a part of the part and a means of rapid shooting, the input of which is also connected to the output of the rotational speed sensor and the output of the rotation control circuit, and a destruction sensor, the output of which is connected to the inputs of the means of rapid shooting and a logic block, the output of which is connected to the output of the unit for recording the speed of rotation of the part, the fact that. in order to improve accuracy by eliminating the imbalance during rotation of the test part, it is equipped with a series-connected electrically frequency multiplier, the input of which is electrically connected to the output of the rotational speed sensor, and the output to the input of the unit for recording the rotational speed of the part, the first harmonic extraction unit, the input of which is electrically connected with the output of the measuring amplifier, and the output with the device for automatic balancing, the inputs of which are electrically connected to the outputs of the logic unit, multiply eating frequency and rotation control circuit