JP3276204B2 - Low temperature measurement system for elasticity, internal wear and sound velocity - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to metal, ceramics,
Total elasticity for samples composed of various solid materials such as polymers,
The present invention relates to an apparatus for measuring changes in internal wear and sound velocity at low temperatures, and more particularly, to an apparatus which can measure physical properties of a sample under a low temperature condition from 0 ° K. to room temperature using an ultrasonic pulse.

[0002]

2. Description of the Related Art Conventionally, as a device for measuring physical properties of various solid materials such as metals, ceramics, polymers, and the like with respect to changes in elastic modulus, internal wear, and sound speed, a tensile and compression tester, As for friction, a measuring instrument based on a resonance method is known.

However, in material design and evaluation of physical properties of various solid materials, Young's modulus, rigidity, bulk modulus,
The compression ratio, Lame parameter, Poisson's ratio, longitudinal wave velocity, shear wave velocity, sound velocity anisotropy coefficient, and longitudinal and lateral internal friction are regarded as important physical properties. Therefore, development of an apparatus capable of measuring all of these 11 physical property values under a wide range of temperature conditions has become an important issue.

In view of the above, in the present invention, the use of an ultrasonic wave guide makes it possible to obtain data relating to the physical properties of a sample in a short time and with high accuracy, and to obtain a low change in the elastic modulus, internal wear, and sound velocity. It is intended to provide a measuring device in a region.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an ultrasonic waveguide is formed of a rod-like body having irregularities on its outer peripheral surface, and is inserted into a cryostat. At one end, a sample for measuring physical properties related to changes in elastic modulus, internal wear, and sound speed is attached. At the other end outside the cryostat, a heater or a hot water jacket and a transmitter / receiver for ultrasonic pulses are attached. Is provided.

[0006]

[0007]

The low-temperature measuring device of the present invention for measuring changes in elastic modulus, internal wear, and sound speed is constructed so that the sample can be attached to the ultrasonic waveguide, so that the operability at the time of measurement is simplified and the sample is easily measured. This expands the range of use for measurement.

Also, regarding the changes in the elastic modulus, internal wear, and sound velocity, the ultrasonic pulse is applied to the sample via a longitudinal or transverse ultrasonic waveguide.
By calculating the propagation time and attenuation rate of the same pulse,
This allows measurement in an arbitrary temperature range. Further, it is not necessary to cool the sensor to a low temperature part, and one sensor may be used instead of the four sensors for receiving and transmitting longitudinal and transverse waves.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the low-temperature measuring apparatus for elastic modulus, internal wear and sound velocity of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes an ultrasonic wave guide composed of a rod-shaped body having an outer peripheral thread formed on an outer peripheral surface, a part of which is inserted into a cryostat 2 whose temperature can be adjusted.
The sample 2 is attached to the insertion end.

For example, in the case of FIG. 1, a sample 3 having a substantially T-shaped cross section in which a flange 3b is formed at one end of a shaft portion 3a is applied, and the sample 3 is provided with a cap nut via a couplant 4 in the case of FIG. It is attached by the holder 5. The couplant 4 is interposed for the purpose of protecting the ultrasonic waveguide 1 and improving the transmission of the ultrasonic pulse. For example, Au, Pt, Ta, SUS, Cu, Ni, etc. Metal, Teflon, vinyl, beeswax, silicon grease, etc. are appropriately selected depending on the applicable temperature range. However, a couplant is not necessarily required if the surface accuracy is improved.

The cryostat 2 is mounted on an upright shaft of an apparatus main body (not shown), and is preferably capable of controlling the temperature from 0 ° K to room temperature.

The ultrasonic waveguide 1 has an end opposite to the insertion end protruding from the cryostat 2, and a heater 8 and an ultrasonic pulse transmitter / receiver 9 are provided at the opposite end. Provided. The heater 8 can also be applied to a warm water jacket. The reason for its existence is to keep the transmitter / receiver 9 at room temperature by keeping it warm.

Thus, the ultrasonic waveguide 1 is usually
A sample 3 having an equal or close acoustic impedance is applied. The reason for this is to measure the internal friction with high sensitivity. Further, a material having low ultrasonic wave propagation loss and cold resistance is preferable. For example, it is made of SUS, high-density graphite, SiC, Si3N4 based sintered body. In this case, the reason why the unevenness is formed on the outer peripheral surface of the ultrasonic waveguide 1 is to disturb the reflected wave of the ultrasonic pulse on the side surface of the ultrasonic waveguide 1 and prevent noise echo. . This unevenness is intended to form an outer screw in screws cutting tool, in the case of FIG. 1, in which forming the outer peripheral screw 10 over the entire length. The holder 5 is made of a material having a larger coefficient of thermal expansion than the materials of the ultrasonic waveguide 1 and the sample 3. This is to secure the tightening of the sample 3 by the contraction of the holder 5.

The ultrasonic waveguide 1 thus constructed
Basically, physical properties related to changes in elastic modulus, internal wear, and sound velocity measured by the method are as follows: Young's modulus, rigidity modulus, bulk modulus, compression ratio, Lame parameter, Poisson's ratio, longitudinal wave velocity, transverse wave velocity, and sound velocity difference. The anisotropy coefficient and the longitudinal / lateral internal friction are 11. In this measurement, for example, as shown conceptually in FIGS. 1 and 2, the measurement is performed by the sing-around unit 11 via the transceiver 9. In this case, single around unit 1
1 is connected to a waveform monitor 12 and a personal computer 13 for monitoring or printing out a measurement result, and the personal computer 13 is connected to a display 14 and a printer 15.

FIG. 3 shows the single-around unit 1.
1 shows an example of a measurement system diagram, in which an ultrasonic pulse generated by a transmission circuit 16 is transmitted and received by a transmitter / receiver 9 → an ultrasonic waveguide 1 → a sample 3 → an ultrasonic waveguide 1 → a transmitter / receiver 9 → an amplifier 17. The circuit circulates through the path of the zero-cross detector 18, the multi-stage delay circuit 19, and the transmission circuit 16, and a single-around measurement system is constituted by this closed circuit. In this case, the transmitter / receiver 9 moves toward the sample 3 as shown in FIG.
Longitudinal ultrasonic wave pulses emitted propagates through the ultrasonic waveguide 1 is reflected by the contact side surface of the sample 3, the ultrasonic pulse 20 to be received Sojushinko 9 T _o 'time, It is divided into ultrasonic pulses 21 and 22 incident on the sample 3. And
These ultrasonic pulses 21 and 22 are an ultrasonic pulse 21 in a longitudinal wave → longitudinal wave mode and an ultrasonic pulse 22 in a longitudinal wave → lateral wave → longitudinal wave mode. It is received Sojushinko 9 ₁ 'and T _2' time.

In the closed circuit of the single-around unit measurement system described above, there are provided a peak detector 23 for detecting the peak value of the ultrasonic pulse and an AGC amplifier 24 for always making the amplitude of the ultrasonic pulse a constant peak value. At the same time, the time when the received pulse voltage crosses the zero voltage (zero point) is measured by the zero cross detector 18.
The multi-stage delay circuit 19 is inserted to eliminate an error due to multiple echoes of the ultrasonic pulse in the sample 3.
It is constituted by an ultrasonic delay line and a feedback circuit, and generates an accurate delay time that is an integral multiple of the delay time of the delay line. When the average period of the sing-around group is measured n times, n times higher measurement accuracy is obtained from the principle of the period measurement, and highly accurate propagation time measurement becomes possible.

Further, in this closed circuit, a window gate 25 and a counter 26 are set, and the propagation times T ₀ ′, T ₁ ′ and T ₂ ′ of the ultrasonic pulses 20, 21 and 22 are set.
Is measured. This measurement value is transmitted to the RS-
This is output from the serial interface 28 of the 232C standard processing. In this automatic measurement, software connected in a closed circuit is subjected to arithmetic processing by the CPU 29 which is a computer control unit.

FIG. 3 is a supplementary explanation of FIG. 2 and is a time chart of ultrasonic pulses.

That is, the transmission pulse 30,
The received signal 31, the output signal 32 of the window gate 25, the output signal 33 of the zero-cross detector 18, and the output signal 34 of the multi-stage delay circuit 19 are shown.

4 (a) to 4 (c), the ultrasonic pulse incident on the sample 3 from the ultrasonic waveguide 1 at time T ₀ is, as shown in FIG. It is composed of a longitudinal wave 35 parallel to the central axis and a longitudinal wave 36 having a directivity angle with the central axis. In this case, if the side surface of the sample 3 is finished flat, the longitudinal wave 36 is reflected on the side surface of the sample 3 and is divided into a longitudinal reflected wave L36 and a transverse reflected wave S36. However, as shown in FIG. 4B, the longitudinal reflected wave L36 disappears at the critical angle θ, and only the transverse reflected wave S36 exists. Then, when the acoustic velocity of the longitudinal waves 35 and shear waves S36 in sample 3 V _L, and V _S (1) expression of relation is established.

[0022]

(Equation 1) Further, in FIG. 4B, the ultrasonic pulse 35 is reflected on the end face of the sample 3 and is incident on the ultrasonic waveguide ₁ at the time T1, and the ultrasonic pulse 36 is a longitudinal wave → lateral wave → vertical wave. while converting a wave incident on the ultrasonic waveguide 1 at time T ₂ is reflected by the end surface of the specimen 3. As a result, the sound speeds of the longitudinal wave and the transverse wave are obtained from the length L and the diameter D of the sample 3 from FIG.
It is obtained by the equations (2) and (3). However,
L >> Dtan θ.

[0023]

(Equation 2)

[0024]

(Equation 3) In contrast, the acoustic velocity V _L of the longitudinal wave-shear in the sample 3, the density of V _S and the sample 3 [rho, solid elastic various constants (4) -
It is given by equation (10).

[0025]

(Equation 4)

[0026]

(Equation 5)

[0027]

(Equation 6)

[0028]

(Equation 7)

[0029]

(Equation 8)

[0030]

(Equation 9)

[0031]

(Equation 10) The ultrasonic pulse 35 shown in FIG. 4B is incident on the ultrasonic waveguide ₁ at time T ₁ , is reflected on the end face of the sample 3, and again passes through the same path and the ultrasonic pulse echo. next, it enters the ultrasonic waveguide 1 at time T _3.

FIG. 4C shows the relationship between the propagation time of the ultrasonic pulse and the peak value A of the amplitude of the ultrasonic pulse at the time T ₂ and T ₃ of the longitudinal and transverse waves reflected from the sample. ₁ and A ₂ are shown respectively. From the peak values A ₁ and A ₂ , if the reflection at the interface is total reflection, the internal friction Q ⁻¹ of the sample 3 is given by the equation (11).

[0033]

[Equation 11] By the way, as described above, the times T ₀ ′, T ₁ ′ and T ₂ ′ output from the serial interface 28 are:
3 and FIGS. 4 (a) to 4 (c) show the time relationship of equation (12).

[0034]

(Equation 12) In the equation (12), T ₀ ′ is obtained from the sing-around period, and T ₁ ′ and T ₂ ′ are obtained from the wind gate 25.
Are sequentially set for the measurement of the ultrasonic pulses 22 and 23.

From the equations (2), (3) and (12), the longitudinal and transverse wave velocities V _L and V _S are obtained, and the peak values of the amplitudes of the received pulses 21 and 22 are respectively represented by A ₅ and A _5. Assuming that A ₆ , the internal friction Q ^-1 is given by the equation (13) by the equation (11).

[0036]

(Equation 13) In the equation (13), C is the effective cross-sectional area change rate S between the ultrasonic waveguide 1 and the sample 3 and the reciprocating effective sound pressure transmissivity T of the ultrasonic pulse including both the couplant 4. , C = S / T. Therefore,
The value of C may be input to the CPU 29 in advance. Further, the peaks A ₅ and A ₆ of the reception pulses 21 and 22 described above are detected by the peak detector 23, and the I / O is detected.
The signal is output from the serial interface 28 via the interface 27.

The effective reciprocating sound pressure transmissivity T is obtained by calculating the acoustic impedance of each of the ultrasonic waveguide 1 and the sample 3 by Z _1.
If the couplant 4 is ignored for Z and Z ₂ , (14)
Where A ₆ / A ₅ is given by equation (15).

[0038]

[Equation 14]

[0039]

(Equation 15) In order to measure the internal friction with high sensitivity, (15)
As is apparent from the equation, the acoustic impedances of the ultrasonic waveguide 1 and the sample 3 are equal over the measurement temperature range (Z
₁ = Z ₂ ) or close to each other (Z ₁ ≒ Z ₂ )
It is desirable to constitute the material. Further, in order to receive the stable reception pulses 21 and 22, it is necessary that the propagation loss in the ultrasonic waveguide 1 is small.

According to the present invention, it is possible to measure the Young's modulus, the rigidity, the bulk modulus, the Lame parameter, the Poisson's ratio, the longitudinal wave speed, the transverse wave speed, the sound velocity anisotropy coefficient, and the longitudinal / lateral internal friction in this manner. I mentioned.

In this embodiment, a vertical measuring device is exemplified, but the present invention can be applied to a horizontal measuring device. Further, although the case of using the single-around unit 11 as the measurement system of the ultrasonic pulse has been described, the case of the pulse echo method in which the time interval from the transmission pulse to the reception pulse is measured can also be applied.

[0042]

According to the present invention, as described above, ultrasonic waves waveguide 1 Contact and sample 3 by transmitting and receiving ultrasonic pulses, the sample 3 from the propagation time and attenuation rate of the sample 3 which is processing It is designed to be able to measure changes in elastic modulus, internal wear, and sound speed under a wide range of low-temperature conditions. Therefore, Young's modulus, rigidity, bulk modulus,
It can simultaneously measure changes in total dynamic elasticity such as the Lame parameter, Poisson's ratio and longitudinal and lateral internal friction, internal wear, and sound speed. As a result, there is an advantage that a wide range of data required for material design can be provided in a short time and with high accuracy.

[Brief description of the drawings]

FIG. 1 is a conceptual explanatory view showing one embodiment of a low-temperature measuring apparatus for elastic modulus, internal wear, and sound velocity according to the present invention.

FIG. 2 is a system diagram showing a measurement system in a sing-around unit.

FIG. 3 is a time chart for supplementarily explaining FIG. 2;

4A and 4B are explanatory diagrams of a path and a time of an ultrasonic pulse in a sample. FIG. 4A is a path diagram of an ultrasonic pulse from an ultrasonic waveguide, and FIG. The path diagram of the shear wave reflected wave by the critical angle θ of the ultrasonic pulse, FIG.
It is a relation diagram of the propagation time of an ultrasonic pulse and an amplitude peak value.

[Explanation of symbols]

 1, 1a, 1b Ultrasonic wave guide 2 Cryostat 3 Sample 5 Cap nut 7 Embedded screw 8 Heater or hot water jacket 9 Transceiver 9a Transmitter 9b Receiver 10 Outer thread 11 Singaround unit 20, 21, 22 Ultrasonic pulse

Continuation of the front page (56) References JP-A-6-58913 (JP, A) JP-A-5-215728 (JP, A) JP-A-63-246654 (JP, A) JP-A-2-141463 (JP, A) , A) JP-A-2-305301 (JP, A) Jikken Sho 43-7675 (JP, Y1) Mikio Fukuhara, Simultaneous measurement of physical properties of high-temperature materials using ultrasonic pulses-Total dynamic elastic modulus such as Young's modulus, Poisson's ratio, vertical and horizontal wear-New Ceramics, October 1992, Japan, September 25, 1992, VOL. 5 / NO. 10 / PAGE. 77-82 (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 29/00-29/28 JICST file (JOIS)

Claims (2)

(57) [Claims] A transceiver is provided at one end of an ultrasonic waveguide.
At the other end, a sample is attached by a holder.
At the same time, this sample is
Elastic modulus, inner wear, and sound that allow sound wave pulses to be transmitted and received
In the low temperature measuring device of speed, the ultrasonic waveguide, along the outer peripheral screw is formed on the outer peripheral surface thereof, a part thereof is inserted into a temperature adjustable within the cryostat of the low temperature region, or vice versa At the end,
A heater or a hot water jacket for holding the transmitter / receiver in a normal temperature state is provided, and the sample has a cross-sectional shape in which a flange is formed at one end of a shaft portion.
The holder is made of a T-shaped rod, and the holder is more thermally expanding than the ultrasonic waveguide and the sample.
Formed of a large number of materials, and the ultrasonic waveguide
By configuring a cap nut to be screwed into the outer thread,
A flange portion of the sample is attached to the sample, and the transmitter and receiver are arranged so that a longitudinal ultrasonic pulse is applied to the sample.
When the longitudinal wave and the transverse wave are received,
In both cases, this transmitter / receiver has a repetitive ultrasonic pulse
The measurement system units that constitute the same closed circuit
Propagation time measured by transmitting and receiving ultrasonic pulses
Calculates the elastic modulus, internal wear and sound of the sample
Elastic modulus being characterized in that so as to measure the speed, the inner Worn, sound speed of the low-temperature measurement device. Wherein said ultrasonic waveguide has an elastic modulus of claim 1 Symbol mounting consists substantially equal material to the acoustic impedance of the sample, the inner Worn, sound speed of the low-temperature measurement device.