JPH0643953B2 - Method and apparatus for measuring solid resonance frequency for deriving Young's modulus and internal friction - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a method and apparatus for resonating ceramics, metal, plastic, wood, etc. to derive Young's modulus and internal friction, and measuring the resonance frequency in that case. It is related to a wide temperature range (-
It can be measured at 250 ° C to 1500 ° C).

(B) Problems of the prior art As a method of measuring the Young's modulus of a conventional solid and the resonance frequency of the solid for deriving the internal friction, a sample 1 as shown in FIG. 2 is suspended by two platinum wires 7. There is a method of making it resonate. 10 is a heating furnace body, 8 is a shaker, and 9 is a detector. In this method, the suspension platinum wire resonates, the resonance frequency of the measurement sample is difficult to find, and the platinum wire is thick, so the vibration loss generated there is large. Further, since the hanging point is a node of vibration, the efficiency of resonating the sample is poor and the error of the measured value of the resonance frequency is large. Moreover, in this method,
Since the hole (10 ') is opened in the upper part of the furnace body, it is difficult to adjust the atmosphere.

(C) Disclosure of the Invention When measuring the resonant frequency of a solid material for deriving the Young's modulus and internal friction of the material by the resonance method, it is important how to vibrate the sample efficiently. As a result of various studies to solve the problems, the present invention has been achieved.

The feature of the present invention resides in that an electrode is provided on either side surface of the plate-shaped measurement sample by applying a paste having conductivity and heat resistance. This has made it possible to accurately measure the resonance frequency of non-conductive ceramics, wood, plastics, etc. in various atmospheres and wide temperature ranges.

However, in this case, the thickness of the electrode is preferably 0.1% or less of the thickness of the sample in consideration of an error generated during the measurement.

FIG. 3 is a perspective view of Sample 1 used in the measurement of the present invention,
An electrode 11 is provided on one side surface thereof. As shown in FIG. 4, this sample is placed on a jig 2 having two supporting parts with its electrode as the lower surface. The jigs are provided with heat-resistant conductive wires 7A and 7B such as Mo, Ta, and Ni, and the electrode 12 of the sample is placed on the conductive wires 7A and 7B arranged on the supporting portion of the jig. To Reference numeral 13 is a place where the wire on the ground side contacts and is grounded. Incidentally, FIG. 4 is a top view of the state in which the measurement sample is placed on the jig. As shown in FIG. 1, it has heating and cooling means, and the vacuum outlet or the atmospheric gas inlet 4 is provided. It is installed in the container 3 having. still,
The thermocouple 6 is for measuring the temperature of the sample, and the tip of the thermocouple 6 is arranged so as to be slightly separated from the sample so as not to disturb the vibration of the sample. The position may be set, for example, as shown in FIG. 4, but since it is measured in the state where the temperature is in equilibrium, it is not limited as long as it is near the center of the sample. The sample is a conducting wire 7A arranged on the supporting portion of the jig shown in FIG.
And 2B of 7B, the electrode on the sample 11
Comes into contact with these two conductors and is electrically connected,
The conductor 7A on the ground side shown in FIG. 4 is brought into contact with 13 in FIG. 3, and the electrode 11 is the drive electrode 8 in FIG.
It is set to come on top of. An alternating voltage is applied by an alternating voltage source 5 through a conductor 7B between the drive electrode 8 and the electrode 11 provided on the measurement sample to vibrate the sample. At this time, by arranging the driving electrode at the center of the sample, very efficient vibration occurs.

The measurement frequency is not particularly limited, but take into consideration the natural resonance frequency of the material to be measured and the measurement sensitivity of the vibration detector.
50 to 50,000 Hz is preferable.

On the other hand, this vibration is detected by a detector provided in the container 3, for example, a microphone 14 having high sensitivity and high directivity. For the detected vibration, internal friction is calculated from its resonance waveform. On the other hand, Young's modulus is calculated from the following equation by detecting the resonance frequency of the natural lateral vibration obtained from the main vibration.

E = 0.9468 × (L ³ × g) × o ² / (t ³ × w) where E: Young's modulus, L: sample length, w: sample width,
t: sample thickness, g: sample mass, o: resonance frequency.

It is possible to measure up to 1500 ° C. by maintaining the inside of the container 3 at a specific temperature by external heating. At low temperatures, liquid helium is used, and temperatures up to -250 ° C are possible.

The thermocouple is not particularly limited in the present invention as long as it is for measuring the above-mentioned temperature range, and for example, -1400 ° C. includes general chromel-alomer and tungsten-rhenium.

This temperature is measured by placing the thermocouple 6 shown in FIGS. 1 and 3 at an appropriate position near the surface of the sample as described above.

The measurement atmosphere may be a vacuum or a non-oxidizing atmosphere such as Ar or N ₂ . The jig 2 is made of Al ₂ O ₃ or BN so that it can withstand high temperatures. The size of the sample 1 is usually in the range of 1 mm × 5 mm × 20 mm to 3 mm × 15 mm × 150 mm, but it can be set to any other size by changing the dimensions of the jig.

Next, examples will be described.

(D) Example An Al ₂ O ₃ and Si ₃ N ₄ sintered body was used as a measurement sample.
Processed to a size of 5 mm × 10 mm × 60 mm, and Mo
The paste was applied and baked. Using the apparatus shown in FIG. 1, the sample was resonated at room temperature and high temperature to confirm its resonance frequency and its waveform, and Young's modulus and internal friction were calculated from this. The result is shown in FIG. White circle (E1), black circle (E
2) is Young's modulus calculation value of Al ₂ O ₃ and Si ₃ N ₄ , respectively, and white corner (Q2) and black corner (Q1) are internal friction calculation value of Al ₂ O ₃ and Si ₃ N ₄ , respectively.

In FIG. 5, calculated values of Young's modulus of Al ₂ O ₃ and Si ₃ N ₄ at room temperature are shown by E1 (RT) and E2 (RT). Comparing this measured value with the calculated value of elastic modulus by the ultrasonic method defined by JIS, the measured value is the average value of the measurement results of 10 times repeated, and the difference is within ± 0.5%, showing a good agreement. As a result, the effect of the present invention has been clarified.

[Brief description of drawings]

FIG. 1 is a front sectional view of a measuring apparatus of the present invention, FIG. 2 is an explanatory view of a conventional measuring method, FIG. 3 is a perspective view of a sample used in the measurement of the present invention, and FIG. 4 is a sample of the present invention. The top view showing the set state and FIG. 5 are the calculation results of the Young's modulus and the internal friction of the embodiment by the measuring method and apparatus of the present invention. 1: sample, 2: jig, 3: container, 4: exhaust port or inlet port, 5: alternating voltage source, 6: thermocouple, 7: platinum, 7, 7
C: conductor for applying alternating voltage, 7A, 7B: sample conductor, 8:
Drive electrode, 9: Detector, 10: Furnace body, 10 ': Hole, 11: Electrode, 12: Electrode (sample), 13: Earth side wire overlap point, 14: Vibration detector, 15: Jig sample support Part, E1: Al ₂ O ₃ Young's modulus, E2: Si ₃ N ₄ Young's modulus, Q1: Si ₃ N ₄ internal friction, Q2: Al ₂ O ₃ internal friction.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Omura 1-1-1 Kunyokita, Itami City, Hyogo Prefecture Sumitomo Electric Industries, Ltd. Itami Works (56) Reference JP-A-58-148954 (JP, A) Japanese Patent Publication Sho 29-2697 (JP, B1)

Claims (4)

[Claims] 1. A method for measuring a resonant frequency of a solid for deriving a Young's modulus and an internal friction of the solid, which is a plate-like solid sample having an electrode having a conductive and heat resistant property on either side thereof. And supporting this sample at a specific interval, and mounting it on a jig having heat resistance in which a conductive wire that comes into contact with the electrode part of the sample is attached to the supporting part, and Corresponding to the ambient temperature, which is characterized in that an alternating voltage is applied between it and a driving electrode provided on the jig so as to co-vibrate the sample, and the ambient temperature is changed for measurement. Measuring method of resonance frequency of solid. 2. The frequency at which the sample resonates is 50 Hz to 5000.
Claim (1) characterized in that it is in the range of 0 Hz
Item 7. A method for measuring the resonance frequency of a solid according to the item. 3. The method for measuring the resonance frequency of a solid according to claim 1, wherein the measurement temperature range is −250 ° C. to 1500 ° C. 4. A jig 2 having heat resistance is installed in a container 3 equipped with heating and cooling means, and a conductive wire for applying a voltage from an alternating voltage source 5 to a conductive portion 8 of the jig 2. One side 7C is attached, and this conductive portion 8
Is used as one of the drive electrodes, and the jig 2 has non-conductive and heat-resistant wires 7A and 7B having conductive and heat-resistant properties mounted on the upper surface for supporting the plate-shaped solid sample 1 to be measured. A pair of projecting support portions 15 having
Conductor 7 connected to the conductors 7A and 7B and the conductor 7C
The plate-shaped sample 1 having the conductive and heat-resistant electrodes 11 provided on the side surfaces is set so that an alternating voltage is supplied through the electrodes, and the electrodes 11 and the jig 2 on the plate-shaped sample 1 facing each other are set.
Detector for detecting the co-vibration of the plate-shaped sample 1 caused by applying an alternating voltage to the upper drive electrode 8.
An apparatus for measuring the resonance frequency of a solid for deriving the Young's modulus and internal friction of the solid, which is equipped with a thermocouple 6 for measuring the ambient temperature of the sample.