JPS6142217B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring internal friction of metallic materials using a low frequency torsional pendulum method.

Conventionally, methods for measuring internal friction of metal materials include a free damping method and a constant amplitude method. In the free damping method, first, the drive device applies torsional vibration of a constant amplitude to the sample, and then the drive device is deenergized to produce free damping vibration.
Calculate the logarithmic damping rate at that time and calculate the internal friction (Q ^-1 )
=1/π 1/nlogA ₀ /An (A ₀ : initial amplitude, A _o
: amplitude at the nth vibration).The constant amplitude method supplies energy to the drive device so that the sample maintains the torsional vibration of the set amplitude, and calculates the internal friction of the sample from the change in energy. It is something to seek. The former method can directly determine internal friction, but it takes time and cannot be recorded continuously, and accurate results cannot be obtained with amplitude-dependent materials. On the other hand, the latter can measure changes in internal friction continuously and is suitable for measuring amplitude-dependent materials, but since the absolute value of internal friction is not known, it cannot be compared with the results of the free damping method. You have to ask for it. Conventional equipment for carrying out the free decay method uses an electromagnet to attract a piece of iron to give a certain amount of twist to the sample, but since internal friction changes with temperature, the attraction force must be adjusted accordingly. Otherwise, the iron piece would be sucked in with a force greater than necessary, which would give a large impact to the torsion system including the sample, and the vibrations caused by this impact would cause errors in measurements. In addition, in order to alleviate this impact, it is necessary to adjust the suction force of the iron piece according to the internal friction, but it has been difficult to automate this process.

The object of the present invention is to provide an internal friction measuring device that eliminates the drawbacks of the conventional free damping method described above and can also perform the constant amplitude method. A drive device consisting of a movable wire ring and a permanent magnet etc. that give torsion, a switch inserted into the energizing circuit of the drive device, a device that generates an electric signal proportional to the amplitude of torsional vibration, and a device that detects deviation from a constant amplitude and detects the deviation from the constant amplitude. A circuit for generating a drive signal or a damping signal for the drive device corresponding to the deviation, and at the start of torsional vibration, the switch is closed and the drive signal or damping signal generated in the circuit is supplied to the drive device; and a sequence controller for sustaining constant amplitude torsional vibration on the sample, the sequence controller being able to selectively perform a free damping method and a constant amplitude method on the sample, and causing the free damping method to be performed on the sample. The present invention is characterized in that the switch is opened and the constant amplitude torsional vibration of the sample is stopped.

The present invention will be explained below with reference to the drawings.

FIG. 1 shows a schematic diagram of an embodiment of the invention. What is shown on the left side of the figure is a mechanism for applying torsional vibration to the sample.

1 is a sample to be measured, 2 is a chuck, 3 is a shaft attached to the chuck 2, 4 is a drive device consisting of a movable wire and a permanent magnet that rotates the shaft 3, 5
6 is a ferrite disk fixed to both ends of an arm fixed to the shaft 3, and 7 is a ferrite pot core that faces the ferrite disk 6 and houses a coil inside. , installed on a substrate 8 supported by bearings 9. This disk 6 and pot core 7 constitute a displacement detector. The substrate 8 is configured to be rotated via an arm 12 by a cam 11 rotated by a motor 10. 13 is a counterbalance for maintaining constant tension on the sample 1; 14 is an inertia weight; 15 is a heating furnace; 16 is a heater; and 17 is a thermocouple.

The other configuration shown in the figure is a block diagram of a circuit that supplies drive energy to the drive device 4 of the mechanism, torsionally vibrates the shaft 3, that is, the sample 1, and measures the internal friction of the sample.

20 is a displacement detection circuit that generates an output voltage proportional to the twist as the inductance of each coil housed in the pot cores 7 increases and decreases when twist is applied to the sample 1, resulting in an unbalanced circuit; 21; 22 is a constant amplitude circuit that detects a deviation signal from the constant amplitude in order to maintain the torsional vibration of the sample 1 at a constant amplitude, and generates an operating signal for the drive device 4 based on that signal; 22 is an output circuit that uses its output to operate the drive device; energize 4. 23 is a servo amplifier that drives the servo motor 10 with its output. A closed loop formed when the switch 37 is closed, consisting of the ferrite disk 6, the pot core 7, the displacement detection circuit 20, the servo amplifier 23, the motor 10, the cam 11, the arm 12, and the board 8, constitutes a Gallo point adjustment mechanism. do.

24 is a damping rate meter, and when the torsional vibration of sample 1 freely damps and reaches the set amplitude (1/πlogA ₀ /A ₀ ), it measures 100% (constant amplitude) and 100% or more of a predetermined amplitude (e.g.
103%), which generates output when it becomes 2
5 is the knob that sets 1/πlogA ₀ /A _o , 26 is 100%
The gate is opened until the amplitude is attenuated to the set amplitude (1/πlogA ₀ /A _o ), and the vibration pulse is allowed to pass during that time. A counter 26 counts the vibration pulses that have passed, and 28 is a damping rate meter 24. 1/πlogA ₀
/A _o and the frequency n until it decays from 100% amplitude to the set 1/πlogA ₀ /A _o and internal friction (Q ^-1 ) = 1/π 1/
A digital arithmetic circuit that calculates n logA ₀ /A _o ; 29 is a sequence controller; for example, two P-ROMs;
(programmable, read, only, memory) and a counter, and when the start switch 30 and constant amplitude vibration switch 32 or free damping switch 33 are closed, it is activated via a start/stop circuit 34 having two flip-flops. Then, constant amplitude vibration or free damped vibration is performed according to the sequence program.

One P-ROM stores a matrix that connects input signals such as a start signal generated by closing the start switch 30 with each process (O~) of the sequence controller, and the other P-ROMs store a matrix that links each process (O~) of the sequence controller. A matrix is stored in memory that links processes and command operations (dump, excitation, free decay, etc.). The counter serves to remember which process the process is currently in. 31 is a stop switch, 35 is a timer that generates an input signal to control the sequence controller 29 at a set time, 36 and 37 are switches controlled by the sequence controller, 38 is a program temperature controller, a programmer 39, and a PID calculation circuit 40. , which is composed of a current control circuit 41 using a silicon controlled rectifier (SCR), supplies power to the heater 16 of the heating furnace 15, and heats the sample 1 at a constant rate, cools it at a constant rate, or maintains a constant temperature after rapid heating according to the program. etc.

45 is a data store circuit which stores the internal friction which is the calculation result of the digital calculation circuit 28, the temperature of the sample 1 taken out through the thermocouple 17, the thermometer 42 and the A-D converter 44, the clock 46, and the counter 47. The extracted period is stored, and the output is displayed, printed, and recorded on the recorder 43 via the display 48, printer 49, and DA converter 50.

Next, the operation of this device will be explained.

(i) When performing the free decay method on a sample, when the free decay switch 33 is pressed and the start switch 30 is pressed, the start/stop circuit 34 is activated.
The sequence controller 29 initiates the start via. In other words, start switch 3
When 0 is pressed, the sequence controller 29 moves from the O process to the I process in response to a start signal and closes the switch 37, as shown in the sequence program of FIG. When the shaft 3 is not at the zero point position, the inductance of each coil of the two pot cores 7 and 7 is large and small, and an unbalanced signal is generated from the displacement detection circuit 20, so the motor 10 rotates the board 8 to bring the shaft 3 to zero. Adjust to the point position. At the same time, the switch 36 is closed to apply a damping current to the coil of the drive device 4 to damp unnecessary vibrations. After 5 seconds,
The process moves to the step based on the output of the timer 35, and a drive current is applied to the drive device 4 from point J. Therefore, sample 1 starts torsional vibration and gradually increases the amplitude.
When the amplitude exceeds 103% of the specified amplitude, the process moves to the output signal of the damping rate meter 24 and starts counting.On the other hand, torsional vibration is detected by the detectors 6 and 7, the displacement detection circuit 20, the constant amplitude circuit 21, and the output circuit 22.
Constant amplitude control is performed by a closed loop circuit consisting of the drive device 4 and the drive device 4, and the amplitude is maintained at 105% of the constant amplitude. When the specified count is reached, the process moves on to start measuring the cycle. When the specified count is reached, the process begins, the switch 36 is turned off, and the drive device 4 is turned off.
is deenergized and freely damped. When it becomes 100% or less, the process moves to the process based on the signal from the damping rate meter 24, the AND gate 26 is opened, and the counter 27 starts counting the vibration pulses f obtained from the constant amplitude circuit 21. When the low level amplitude (1/πlogA ₀ /A _o ) set by the knob 25 of the attenuation rate meter 24 is reached, the process moves to the process based on the signal from the attenuation rate meter 24, and the AND gate 26 is closed to stop counting, and the switch 36 is turned on. A damping current is applied to the drive device 4 from the closing point J to damp the vibration of the sample 1 and stop it. Start switch 30
While the is closed, repeat the process from step O again in the same way as before.

Since 1/πlogA ₀ /A _o set by the damping rate meter 24 and the counter number n of the counter 27 are input to the data calculation circuit 28, division and multiplication are performed here, and internal friction (Q ^-1 )= Calculate 1/π 1/nlogA ₀ /A _o . This internal friction (Q ^-1 ) is stored in the data store circuit 45, printed on the printer 49, and recorded on the recorder 43, together with the period and the sample temperature at that time.

(ii) When implementing the constant amplitude method, press the constant amplitude switch 32 and press the start switch 30, the sequence program for the constant amplitude method will be selected, and the sequence controller 29 will perform the O setting as in the case of the free decay method. The process progresses from 1 to 2, and thereafter the excitation is maintained without moving to the free decay process.

On the other hand, at the same time, the program temperature controller 38 raises or lowers the temperature of the sample 1 at a constant rate according to a predetermined program of the program 39, for example.

Since the internal friction of the sample 1 changes depending on the temperature, if the change in energy applied to the torsional system is measured while the sample 1 is torsionally vibrated with a constant amplitude, it will be proportional to the internal friction. Therefore, if a voltage proportional to the applied energy is detected from the constant amplitude circuit 21 and continuously recorded along with the temperature by the recorder 43, a temperature vs. Q ^-1 curve can be obtained continuously during one temperature increase or temperature decrease process. be able to.

FIG. 3 shows details of the constant amplitude circuit 21 and the output circuit 22.

100 is a linear detection circuit that linearly detects the tenth side and one side of vibration, and 101 is a peak hold/
and reset circuit, the switch 51 inserted in this circuit connects the terminal A to the waveform shaping circuit 59,
The switch 52 is closed by the pulse f (FIG. 4 f) of phase α (FIG. 4 A) outputted via the monostable multivibrator 60, and the switch 52 connects the terminal A to the phase shift circuit 58, waveform shaping circuit 59, and monostable multivibrator. vibrator 6
Pulse g of phase β (Fig. 4A) output through 0
(FIG. 4G), and the circuit 101 is reset every cycle to accurately follow changes. 102 is an adder circuit, 103 is a sample and hold circuit, and a switch 53 inserted in this circuit is a pulse g (FIG. 4G) g' (the generation circuit and waveform are (not shown). 104 is a differential amplifier;
There is a Zener diode 54 inside for reference voltage generation.
and a switch 55 that sets the reference voltage to zero.

105 is a proportional amplifier, 106 is an integral amplifier,
Proportional and integral calculations are performed on both of them. 107 is an adder circuit, 108 is an inversion circuit, 109 is a polarity conversion switch, 22 is the aforementioned output circuit, which amplifies the output of the terminal I 56 and adjusts the amount of attenuation 57 according to the size of the sample 1, etc., and drives the drive device 4. This provides the optimum driving voltage for the

When the switch 36 is closed and the terminal J is connected to the drive device 4, a closed loop is formed as described above, so the amplitude of the vibration is gradually expanded, and the voltage corresponding to the amplitude of the vibration (Fig. 4A) is used to detect displacement. It appears at terminal A via circuit 20. This voltage is detected by a linear detection circuit 100, and a peak hold and reset circuit 101 holds the peak values on the 10 and 1 sides (Fig. 4B and C), and the peak values on the 10 and 1 sides are output to the adder circuit. 102 (FIG. 4D) to obtain a constant output corresponding to the amplitude of the vibration of the sample and hold circuit 103 from the tenth peak to the -peak. (Fig. 4 E) This voltage e at point E is compared with the reference voltage set by the Zener diode 54 in the differential amplifier 104, and when it is higher than the reference voltage, a difference voltage of 1 is output, and when it is lower than the reference voltage, a difference voltage of 10 is output. . This voltage is subjected to proportional integral calculation by a proportional amplifier 105 and an integrating amplifier,
The adder circuit 107 adds the signals, and the inverter circuit 108 inputs the signals as they are or after inverting the polarity to the polarity change switch 109 at the next stage. Since the two switches of the switch 109 are alternately closed with a voltage h (H in FIG. 4) that is 90° out of phase with respect to the vibration waveform,
From the terminal I, a rectangular wave voltage (I ₁ , I ₂ in FIG. 4) is generated which is shifted by 90 degrees from the vibration waveform and has mutually opposite phases when higher and lower than the reference voltage. When the voltage at point E is higher than the reference voltage, the amplitude of the vibration is larger than the constant amplitude, so a rectangular wave voltage (I ₁ in FIG. 4) whose phase is delayed by 90 degrees with respect to the vibration waveform is sent through the output circuit 22. If applied to the coil of the drive device 4, the vibration will be attenuated, and when the voltage is lower than the reference voltage, the amplitude of the vibration will be smaller than the constant vibration. If I ₂ ) is applied to the drive device 4, the vibration will increase. In this way, the closed-loop control maintains vibrations at a constant amplitude.

To generate free damping vibration, open the switch 36 and de-energize the drive device 4. To dump, close the switch 55 in the differential amplifier 104 by a signal from the sequence controller 27, and the terminal I A voltage having a phase that damps the vibration is generated, and as a result of this voltage being applied to the drive device 4, the vibration stops rapidly.

When implementing the constant amplitude method, the change in energy given to the torsional system corresponding to internal friction, in this example, the change in the current flowing through the drive device 4, and therefore the change in voltage h, is extracted from point k and applied to the recorder 43. and record it.

FIG. 5 is an electrical circuit diagram of the attenuation rate meter 24, and the terminal
E' is a terminal connected to the terminal E of the constant amplitude circuit 21, to which a DC voltage corresponding to the vibration amplitude of the sample 1 is applied, and is connected to one input terminal of each of the comparators 60, 61, and 62. The comparator 60 generates an output when the vibration amplitude exceeds 103%, the comparator 61 generates an output when the vibration amplitude becomes 100% or less, and each of the other input terminals is a potentiometer connected to a constant voltage power supply 63. Each is connected to a predetermined tap on the meter 64. The comparator 62 detects that the vibration amplitude has attenuated to a predetermined amplitude (1/π logA ₀ /A _o ), and the other input terminal has the amplitude (1/π logA ₀ /A _o )=0.1, 0.2, 0.3. is connected to a movable contact piece 66 of a switch 65 which is switched and connected to the tap position of each corresponding potentiometer 64. The output of each comparator 60, 61, 62 is led to the sequence controller 29.

The switch 65 constitutes an interlocking switch,
When the movable contact piece 66 is switched by the knob 25, the movable contact piece 67 is also switched at the same time, and a predetermined amplitude (1/πlogA ₀ /A _o ) corresponding to the tap position is input to the digital calculation circuit 28 as a digital quantity.

In this way, the present invention includes a drive device that applies torsion to the sample, a switch inserted into the energizing circuit of the drive device, a generator for generating an electric signal proportional to the amplitude of the torsional vibration, and a constant amplitude circuit. When carrying out the method, by turning on the switch, it is possible to smoothly apply a torsion of the specified amplitude at the start.
In addition, if the switch is kept closed, the constant amplitude method can be performed, so either of the two methods can be selected and implemented at any time, and furthermore, it has the advantage of facilitating automatic measurement. .

[Brief explanation of the drawing]

Fig. 1 is a mechanism and block diagram of an embodiment of the present invention, Fig. 2 is a sequence program diagram of a sequence controller, Fig. 3 is an electric circuit diagram of a constant amplitude circuit and an output circuit in the present invention, and Fig. 4 is a diagram of each part. FIG. 5 is an electric circuit diagram of the attenuation rate meter in the present invention. DESCRIPTION OF SYMBOLS 1...Sample, 2...Chuck, 3...Shaft, 4...Drive device, 6...Ferrite disk, 7
...Ferrite pot core, 8...Substrate, 10...
...Motor, 11...Cam, 16...Heater, 17
... Thermocouple, 20 ... Displacement detection circuit, 21 ... Constant amplitude circuit, 24 ... Attenuation rate meter, 26 ... AND gate, 27 ... Counter, 28 ... Digital calculation circuit, 29 ... Sequence controller, 30
...Start switch, 32...Constant amplitude vibration switch, 33...Free damping switch, 36, 37...
...Switch, 38...Program temperature controller, 4
2... Thermometer, 43... Recorder, 45... Data store circuit, 48... Display, 49... Printer, 100... Linear detection circuit, 101... Peak hold and reset circuit, 102... Addition circuit , 103...sample hold circuit, 104...
... Differential amplifier, 108 ... Inverting circuit, 109 ...
Polarity conversion circuit.

Claims (1)

[Claims] 1. A drive device consisting of a movable wire ring and a permanent magnet etc. that give torsion to the sample, a switch inserted into the energizing circuit of the drive device, a device that generates an electric signal proportional to the amplitude of torsional vibration, and a device that generates an electric signal proportional to the amplitude of the torsional vibration. a circuit that detects a deviation of the drive device and generates a drive signal or a damping signal for the drive device corresponding to the deviation; and a circuit that closes the switch at the start of torsional vibration and transmits the drive signal or damping signal generated in the circuit a sequence controller that is supplied to the apparatus and sustains constant amplitude torsional vibration on the sample, and the sequence controller is capable of selectively performing a free damping method and a constant amplitude method on the sample; An internal friction measuring device characterized in that, when a damping method is carried out, the switch is opened to stop constant amplitude torsional vibration of the sample.