JPH0758283B2 - Mechanical constant measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical constant measuring apparatus for determining a mechanical constant of a material by exciting the material, detecting the vibration, and calculating the resonance frequency of the material.

[0002]

2. Description of the Related Art Mechanical constants such as elastic modulus and rigidity of materials such as ceramics, metals, plastics and wood can be accurately obtained from resonance frequencies peculiar to the materials.

As an example of a conventional mechanical constant measuring device,
The resonance frequency is calculated by suspending the material with two hanging wires such as platinum wires, exciting the material through these hanging threads, and detecting the vibration of the material while changing the vibration frequency. There is a device that determines the mechanical constant of a material. In this device, since the material and the hanging thread are in contact with each other, when detecting the vibration of the material, the resonance vibration of the hanging thread itself is detected in addition to the resonant vibration of the material itself, and the material is excited. There is a drawback in that the hanging thread absorbs the vibration of vibration when doing so, and the material cannot be efficiently vibrated.

As a conventional mechanical constant measuring device that solves the above-mentioned drawbacks, the resonance frequency of a material is calculated by exciting the material with an alternating voltage and detecting the vibration of the material while changing the vibration frequency. There is a device that determines the mechanical constant of a material.

[0005]

In the latter conventional mechanical constant measuring device described above, in order to obtain the mechanical constant of a non-conductive material, a conductive paste or the like is applied to the material. Electrode must be attached to the material. Therefore, there is a drawback that the mechanical constant of the non-conductive material obtained by the mechanical constant measuring device is affected by the application of the paste. Further, there is a problem that the work of applying the paste also takes time.

The present invention has been made under the above circumstances, and an object of the present invention is to accurately determine the mechanical constant of a material.
Another object of the present invention is to provide a mechanical constant measuring device that can be easily obtained.

[0007]

The present invention relates to a mechanical constant measuring device for determining a mechanical constant of a material by exciting the material, detecting the vibration, and calculating a resonance frequency of the material. The above object of the present invention is achieved by allowing the material to be vibrated by air vibration.

[0008]

The present invention vibrates a material by projecting a sound wave to an arbitrary position of the material to vibrate the material, irradiating a desired position of the vibrated material with laser light, and measuring the reflected light. Can detect the mechanical constant of the material without touching the material.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an example of a mechanical constant measuring device of the present invention, in which a constant temperature container 6 contains a material 1 and a supporting portion 2.
Also, the jig 3 can be housed, and the inside of the constant temperature container 6 can be heated or cooled to a desired temperature by the provided heating means and cooling means. The temperature inside the constant temperature container 6 is detected by the temperature detector 8 and read by the temperature controller 13, compared with the temperature set value instructed to the temperature controller 13 from the electronic computer 15 in advance, and adjusted by the temperature controller 13 according to the result. To be done. Furthermore, by injecting an inert gas into the constant temperature container 6 through the inert gas injection opening 11, the inside of the constant temperature container 6 can be made a non-oxidizing atmosphere.

On the other hand, the amplifier 14 supplies a current to the sound wave generator 5 in accordance with the frequency instructed by the electronic computer 15 to drive the sound wave generator 5. The sound wave generator 5 driven by the amplifier 14 vibrates the material 1 by projecting a sound wave onto the material 1 through the sound transmission tube 4 reaching the material 1 from the sound wave generator 5 through the sound transmission tube opening 9.

The laser Doppler vibrometer 7 detects the vibration of the material 1 by irradiating the material 1 with a laser through the opening 10 for the laser and measuring the reflected light, and shows the time response of the detected vibration waveform. The frequency is analyzed by the frequency analyzer 12 to obtain the resonance frequency. The electronic computer 15 is a frequency analysis device 12
The mechanical constant of the material is obtained by performing calculation using the resonance frequency obtained by the analysis in.

Further, the mechanical constant measuring device of the present invention accurately determines the mechanical constants such as the elastic modulus of the material by appropriately combining the positional relationship between the projection position (excitation position) of the sound wave and the detection position of the vibration. Can be easily obtained. For example, FIG. 2 shows the positional relationship between the support position 18, the vibration position 16 and the vibration detection position 17 of the material 1 when measuring the elastic modulus,
FIG. 3 shows the support position 18 and the vibration position 16 when measuring the rigidity.
And the positional relationship with the vibration detection position 17. As described above, the mechanical constant measuring device of the present invention can obtain an accurate mechanical constant by moving the material position so as to have the positional relationship shown in FIG. 2 or 3 every time the measurement mode changes. .

In the mechanical constant measuring device of the present invention, if a plurality of voice tubes are used or a flexible voice tube is used, the vibration position 16 of the material 1 is not moved without changing the material position each time the measurement mode is changed. Can be moved as shown in FIG. 2 or FIG. A mechanical constant measuring device having a plurality of voice tubes has a valve attached to each voice tube,
By controlling the opening / closing of each valve each time the measurement mode changes, the vibration position can be moved as shown in FIG. 2 or FIG. In the mechanical constant measuring device having a flexible voice tube, the vibration position is changed by moving the voice tube opening 9 every time the measurement mode changes.
Or you can move as shown in Figure 3.

Further, in the mechanical constant measuring apparatus of the present invention, if a plurality of Doppler vibrometers 7 are used, the vibration detecting position 16 of the material 1 can be set to the vibration detecting position 16 of the material 1 without moving the material position each time the measurement mode changes. It can be moved as shown in FIG. The mechanical constant measuring device in this case is installed at a plurality of positions in advance so as to match the position of the Doppler vibrometer and the position of the laser opening 10 with it with the vibration detection position 16 shown in FIG. 2 or 3. Therefore, the vibration at the desired vibration detection position can be detected by selecting the necessary detection signal from the Doppler vibrometer each time the measurement mode changes.

[0015]

As described above, according to the mechanical constant measuring device of the present invention, since the vibration and vibration of the material can be detected without contacting the material, the resonance frequency fluctuation of the material due to the material contact object can be eliminated. It is possible to accurately calculate the resonance frequency of the material, and to obtain an accurate mechanical constant of the material.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of a mechanical constant measuring device of the present invention.

FIG. 2 is a diagram showing a support position, a vibration position, and a vibration detection position of a material when measuring an elastic modulus.

FIG. 3 is a diagram showing a support position, a vibration position, and a vibration detection position of a material when measuring a rigidity.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Material 2 Support part 3 Jig 4 Voice tube 5 Sound wave generator 6 Constant temperature vessel 7 Laser Doppler vibrometer 8 Temperature detector 9 Voice tube opening 10 Laser opening 11 Inert gas injection opening 12 Frequency analyzer 13 Temperature Controller 14 Amplifier 15 Computer 16 Excitation position 17 Vibration detection position 18 Support position

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hideo Yoshidome, 3-6-15 Tenjinyama-cho, Kishiwada-shi, Osaka (72) Inventor Koichiro Otomo 2-272-1018, Yakumohigashi-cho, Moriguchi-shi, Osaka (56) References JP-A-2-134558 (JP, A) JP-A 61-65175 (JP, A) JP-A 58-148954 (JP, A)

Claims (1)

[Claims] 1. A material is excited to detect the vibration,
Machine of the material by calculating the resonant frequency of the material
In a mechanical constant measuring device for determining the mechanical constant, the material
Means for installing the inside to change the temperature of the material
And a container having a cooling means and emits sound waves of a specified frequency.
The generated sound waves are passed through a voice tube connected to the container.
Then, place the material placed in the container at the specified location.
And a sound wave generator that irradiates the material with vibration
Laser Doppler vibration to detect vibration when excited by a vibrating device
And the wave of vibration detected by the laser Doppler vibrometer
The time response function of
Analyze and obtain the transfer function of acceleration, velocity, displacement / force, and
Calculation of the resonance frequency of the material from the transfer function
Mechanical measuring apparatus being characterized in that a means.