JP2003130851A - Elastic parameter measuring device for material surface and coating layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously measure elastic characteristic near surfaces of various materials such as metal, concrete, ceramics including glass, and polymer including rubber, or specimens having coating layers of these materials, by nondestructive contact. SOLUTION: The ultrasonic wave transmitted from a vertical wave/transverse wave simultaneous transmitter 3 built in a sensor 1 is propagated to the specimen 1 through a wedge member 5, and received by two vertical wave/transverse wave simultaneous receivers 4 mounted opposite to each other in an interior angle state. A transmitting angle θ1 and a receiving angle θ2 of the wedge member 5 are determined to propagate the ultrasonic wave to the surface of the specimen 2, the data on the difference in propagation times or an acoustic pressure ratio of the ultrasonic wave on the basis of a distance between two receivers 4a, 4b is taken in a CPU13 to calculate various elastic parameters of the material surface and the coating layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring various elastic parameters near the surface of metal, concrete, ceramics including glass, polymers including rubber, or the like, or a coating layer thereof, which is non-destructive using ultrasonic waves. Therefore, it is possible to perform simple and absolute quantitative measurement.

[0002]

2. Description of the Related Art Conventionally, as a method of measuring fatigue, work hardening, deterioration, etc. of a surface portion or a coating layer in various materials, hardness measurement of a cross section or observation by a scanning electron microscope,
Stress measurement by X-ray irradiation is practically used. Also,
Techniques for measuring various elastic parameters using ultrasonic waves have already been established. This method has the feature that various material properties can be measured with a single measuring device. More recently, a method has also been realized in which ultrasonic waves are excited by laser irradiation to measure the elastic modulus and the like.

[0003]

However, since the excitation method by laser irradiation simultaneously induces heat, it cannot be applied to a metal or polymer having a low melting point, peeling of a coating film or oxidation, and surface treatment. It has the drawback that the effective measurement area below is unclear. In addition, the large size and high cost of the device are also factors that prevent its widespread use.

On the other hand, in the measurement using ultrasonic waves, conventionally, a longitudinal wave probe and a transverse wave probe are alternately fixed to the measured portion, and simultaneous measurement cannot be performed. Moreover, the measurement depth from the surface is limited to more than 1 mm,
It was not possible to measure the material surface or coating layer.

From the above, the present inventor has conducted earnest research with the development of a measuring method in which longitudinal wave probes and transverse wave probes are not fixed to the measuring portion alternately as the greatest problem, and based on a new idea, We have completed a device for measuring the elastic parameters of the material surface and the coating layer by using simultaneous transmission of ultrasonic waves consisting of longitudinal creeping waves and shear horizontal shear waves.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and the invention of claim 1 is various materials such as metal, concrete, ceramics including glass, polymer including rubber, or these materials. It consists of a pair of ultrasonic longitudinal wave / transverse wave simultaneous transmitter (hereinafter referred to as transmitter) and longitudinal wave / transverse wave simultaneous receiver (hereinafter referred to as receiver) for the test object consisting of the coating layer. An elastic parameter measuring device for a material surface and a coating layer in which a sensor capable of measuring elastic characteristics near the surface by non-destructive contact by fixing the measuring sensor is attached. And the receiver are arranged so as to face each other in an internal angle state, and ultrasonic waves composed of longitudinal creeping waves and shear horizontal shear waves (hereinafter referred to as SH waves) are front surfaces of the respective waves. The transmission angle and the reception angle are configured so as to propagate to the arranged wedge members, and the longitudinal and transverse wave acoustic velocities under the surface of the material, the sonic anisotropy coefficient, various elastic moduli (Young's modulus, rigidity modulus, bulk elastic modulus, Compressibility, Lame parameter), Poisson's ratio, Debye temperature, Grenaizen parameter, longitudinal wave / transverse wave attenuation rate, longitudinal wave / transverse wave internal wear, longitudinal wave / transverse wave frequency, linear expansion coefficient and Nyquist diagram It is characterized in that it is formed in.

The first feature of the present invention is to utilize the simultaneous transmitter and receiver of longitudinal and transverse waves of ultrasonic waves. Then, by propagating the ultrasonic wave through the wedge member and appropriately setting the transmitting angle and the receiving angle, the ultrasonic wave can be controlled to propagate on the surface portion of the object to be measured. , It becomes possible to measure various elastic parameters under the material surface at once.

According to a second aspect of the present invention, the sensor has two built-in receivers, and the two receivers are juxtaposed on a straight line connecting the transmitter at a predetermined interval. Characterize. With this arrangement,
The difference in the measurement values caused by the distance between the two receivers can be used, and more accurate measurement can be performed. More specifically, the elastic parameter of the test body is simultaneously measured by taking in the propagation time difference or the sound pressure ratio of the two received waves received by the CPU and performing the calculation and analysis processing.

According to a third aspect of the present invention, the transmitter and the receiver are connected to a pulsar / receiver section for controlling the transmission and reception of ultrasonic waves, and the pulsar / receiver section receives the received wave from the receiver side. It is characterized in that it is connected to an A / D conversion unit for digital conversion, and this A / D conversion unit is connected to a CPU for arithmetic processing having a waveform display function. This makes it possible to provide a complete measuring device incorporating the sensor.

According to a fourth aspect of the present invention, the CPU is composed of a personal computer, and a pulser / receiver section and an A / D conversion section are incorporated in a board of an integrated circuit thereof. This makes it possible to use an existing personal computer and provide a very compact measuring device.

According to a fifth aspect of the present invention, the transmitter and the receiver are composed of two types of piezoelectric domain for longitudinal wave generation and piezoelectric domain for transverse wave generation.
This eliminates the need to attach and combine longitudinal and transverse wave piezoelectric elements in a concentric or half-moon shape as in the conventional type, so that the same longitudinal and transverse wave transmission and reception due to one-sided contact with the measurement surface becomes unstable. There are no shortcomings.

According to a sixth aspect of the present invention, the transmission angle and the reception angle are set so that the longitudinal creeping wave and the transverse SH wave propagate simultaneously at a depth of 1 to 5 wavelengths below the surface of the test body. It is characterized by being The invention of claim 7 is
The transmission angle and the reception angle are set such that the sound pressure ratio of the received waveforms of the longitudinal wave creeping wave and the transverse wave SH wave is in the range of 1/5 to 5/1. Since the wavelength depth and the sound pressure ratio are functions of the transmission angle and the reception angle, it is possible to measure the material surface and the coating layer by adjusting the angle so as to fall within the above numerical range.

The invention according to claim 8 is characterized in that the transmitter and the receiver are piezoelectric elements made of ceramics, polymers, or a composite of ceramics and polymers. Among them, the ceramic piezoelectric element has good sensitivity, but is weak against impact and easily damaged. Since the polymer piezoelectric element is excellent in flexibility, it is not easily affected by the unevenness and roughness of the measurement surface, is resistant to damage, and can transmit and receive high frequency ultrasonic waves, but its sensitivity is not good. . The composite piezoelectric element has good sensitivity, but is weak to impact, low adaptability to surface roughness, and expensive. Thus, these three types of piezoelectric elements are used properly according to the application.

The invention according to claim 9 is characterized in that acrylic is used for the wedge member. Usually, the wedge member is selected from materials having a small difference in acoustic impedance with the test body, ultrasonic wave propagation characteristics, and good wear resistance. For example, metals such as lead, glass such as flint glass, acrylic, polycarbonate, polyimide, polyetherimide, polyetheretherketone, polyamideimide, polyamide, polyethersulfone, polyacetal, polyethylene terephthalate,
Polymers such as ABS resin and modified polyphenylene ether, or rubbers such as silicone rubber, urethane rubber and hiker are used. In addition, acrylic is preferable because the longitudinal wave and the transverse wave are incident and received at substantially the same angle when the steel material that is most often measured is a test body.

The invention of claim 10 is characterized in that the frequency of the ultrasonic wave transmitted from the transmitter is 0.5 to 100 MHz. If the frequency is less than 0.5MHz, the wavelength becomes too long and the measurement accuracy decreases.
This is because it becomes easy to excessively exceed the limit. If more reliable measurement is required, 1 to 20 MHz is recommended.
A pulse wave is used as the ultrasonic wave, because it has a small number of interferences in a complicated manner and has a property that the received waveform can be easily analyzed and the test body can be handled as a solid of an infinite medium.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual explanatory view of a sensor incorporated in the measuring apparatus of the present invention. The sensor 1 is used, for example, when measuring the surface hardening that occurs when a test body 2 made of steel material is quenched. . Inside the sensor 1, one transmitter 3 and two receivers 4 are provided so as to face each other. Then, the receiver 4a on the side closer to the transmitter 3 and the receiver 4 placed apart from the receiver 4a
b are juxtaposed at predetermined intervals on a straight line connecting to the transmitter 3. The transmitter 3 and the receiver 4 are the same substrate piezoelectric element capable of simultaneously transmitting and receiving longitudinal creeping waves and transverse SH waves, and are ceramics, polymers, or composites of ceramics and polymers. It consists of

In front of the transmitter 3 and the receiver 4,
The wedge member 5 is arranged. The ultrasonic wave transmitted from the transmitter 3 is diffracted by the wedge member 5, propagates through the portion directly below the surface of the test body 2, and then is received by the receiver 4 via the wedge member 5 on the receiver 4 side. At this time, the transmission angle θ1 and the reception angle θ2 are adjusted and fixed in advance so that the transmission wave and the reception wave can propagate efficiently. A connection terminal 7 is fixed to a case 6 that forms the outer shell of the sensor 1, and connects a lead wire 8 extending from the transmitter 3 and the receiver 4 and a coaxial cable 9. Transmission angle θ1 and reception angle θ2
Is defined as the angle formed between the normal to the vibrating surface at the transmitter 3 and the receiver 4 and the normal to the ground plane of the sensor.

The transmitter 3 and the receiver 4 are formed of the same substrate in which piezoelectric domains of 100 μm order longitudinal waves and SH waves are alternately dispersed, and are characterized in that they can simultaneously transmit and receive. A longitudinal creeping wave and a transverse SH wave transmitted by the transmitter 3 are propagated to a portion directly below the surface of the test body 2 to measure elastic properties of the material. A pulse wave of 0.5 to 100 MHz is used as the frequency in this case, but 1 to 20 MHz is preferable in order to further improve the reliability of measurement. Although not shown in FIG. 1, a damper for measurement braking is provided behind the transmitter 3 and the receiver 4 to cut noise noise and adjust the number of received waves.

The receiver 4a and the receiver 4b are arranged so as to receive the longitudinal wave creeping wave and the transverse SH wave from the transmitter 3 at a predetermined distance, and the distance between them is measured in the sample. It becomes a place. That is, the transmitter 3 and the receiver 4a
And the sound pressure ratio between the transmitter 3 and the receiver 4b are measured at the same time, so that an error in the electrical system of the measuring device occurs or the transmitter 3 and the receiver 4a are separated from each other. The error caused by the conventional double pressing method of measuring between the transmitter 3 and the receiver 4b subsequent to the measurement at is eliminated, and it is possible to measure the precise propagation time difference or the sound pressure ratio at the distance. Become.

The distance between the receiver 4a and the receiver 4b is 1
It is desirable to be in the range of mm to 100 mm. When it is 1 mm or less, the peak value of the measurement data by the receiver 4a and the peak value of the measurement data by the receiver 4b overlap each other, which makes separation difficult. On the contrary, if there is an interval of 100 mm or more, the longitudinal creeping wave is attenuated and measurement becomes impossible.

The wedge member 5 is designed to reduce the ultrasonic waves,
For steel specimens, the longitudinal wave standard is 850-6000 m / s,
The range of 500 to 3000 m / s on the basis of transverse wave is preferable. This is because when the sound velocity is slow, the ultrasonic wave propagation attenuation becomes large, which causes a problem, and when the sound velocity is fast, the ultrasonic wave incident angle on the test body made of steel cannot be obtained.

As the transmission angle θ1 and the reception angle θ2, the vicinity of the critical angle of incidence of longitudinal and transverse ultrasonic waves is used. This makes it possible to obtain information on the depth of 1 to 5 wavelengths below the surface. Furthermore, it is confirmed that the sound pressure ratio of the received waveform is in the range of 1/5 to 5/1, and the reliability of the measurement just below the surface is improved.

As shown in FIG. 2, the coaxial cable 9 is connected to a pulsar / receiver unit 10 for controlling the transmission and reception of ultrasonic waves, and the pulsar / receiver unit 10 digitally receives the received wave sent from the receiver 4. It is connected to an A / D conversion unit 11 for conversion, and further connected to a CPU 13 for arithmetic processing, which includes a display 12 used for waveform display.
The CPU 13 including the display 12 may be configured by a personal computer 14, and in this case, the pulser / receiver unit 10 is provided on a board (not shown) of an integrated circuit.
If the A / D converter 11 is incorporated, a compact measuring device can be obtained.

The sensor 1 has a transmitting surface 15 and a receiving surface 16.
Is closely attached to the test body 2. The ultrasonic wave is the test body 2
Of the pulser / receiver unit 10 is recognized as a received wave. This received wave is A
The CPU 1 which is converted into a digital signal by the / D conversion unit 11 and includes a display 12 for displaying a waveform
Calculation processing is performed by 3. The CPU 13 uses the measurement results to determine the longitudinal and transverse acoustic velocities under the surface of the material, the sonic anisotropy coefficient,
Various elastic moduli (Young's modulus, rigidity, bulk modulus, compressibility,
Lame parameter), Poisson's ratio, Debye temperature, Grenaizen parameter, longitudinal wave / transverse wave attenuation rate, longitudinal wave / transverse wave internal wear, longitudinal wave / transverse wave frequency, linear expansion coefficient, and waveform and Nyquist diagram Pattern analysis is performed.

The analysis data are compared with the judgment threshold value of the standard sample of the test body 2 to determine the surface deterioration of the material,
Quantitatively diagnosed as hardening and fatigue. Therefore, since the surface portion is measured nondestructively and there is no phenomenon that the SH wave is converted into another mode such as a longitudinal wave, the measurement element can be measured with high accuracy. In addition, if a reference curve for the diagnostic element and the reference value of the measurement element are correlated with the standard sample in advance, and the measured values of the measurement element are compared and judged based on this, a relative curve is obtained. Quantitative diagnosis can be performed with higher accuracy. This calibration curve is also useful when simply making quantitative measurements.

Finally, measurement results using the elastic parameter measuring device for the material surface and the coating layer of the present invention will be illustrated.

[Table 1]

As described above, according to the measuring apparatus of the present invention, a sensor capable of transmitting and receiving at the same time is used, and the transmitting angle and the receiving angle of the wedge members arranged in front of the transmitter and the receiver are proper. By setting to, near the surface of various materials such as metal, concrete, ceramics including glass, polymer including rubber, and coating layers of these,
It becomes possible to measure the elasticity parameter in a single measurement operation with respect to an extremely shallow portion which is difficult with the conventional measuring device. Moreover, by adopting two receivers juxtaposed at a predetermined distance, highly accurate and highly reliable measurement is realized. In addition, this measuring device is compact and lightweight, and since it can be measured relatively easily and in a short time, it can be used in places such as factory processing lines, and it can be used for a wide range of purposes such as checking defective products during processing. Can be used in. Since it is possible to use a ready-made personal computer, it becomes possible to provide a measuring device that is affordable.

[Brief description of drawings]

FIG. 1 is a conceptual explanatory view including a partial cross section of a sensor according to an embodiment of the present invention.

FIG. 2 is a conceptual explanatory diagram of a measuring device according to an embodiment of the present invention.

[Explanation of symbols]

1 sensor 2 test bodies 3 Longitudinal wave / transverse wave simultaneous transmitter 4,4a, 4b Longitudinal wave / transverse wave simultaneous receiver 5 wedge members 10 Personal receiver section 11 A / D converter 13 CPU 14 personal computer θ1 transmission angle θ2 reception angle

Claims (10)

[Claims] 1. A longitudinal wave of ultrasonic waves is applied to a test body formed of various materials such as metal, concrete, ceramics including glass, polymer including rubber, or a coating layer thereof.
By fixing the measurement sensor composed of the pair function of the simultaneous shear wave transmitter and the simultaneous shear wave and shear wave receiver,
A device for measuring elastic parameters of a material surface and a coating layer, which incorporates a sensor capable of measuring elastic properties near the surface by non-destructive contact, including a longitudinal wave / transverse wave simultaneous transmitter and a longitudinal wave / transverse wave. The simultaneous receivers are arranged so as to face each other in an internal angle state, and furthermore, ultrasonic waves composed of longitudinal creeping waves and shear horizontal shear waves are propagated to the wedge members arranged in front of each of them. The transmission angle and the reception angle are configured, and the longitudinal and transverse wave velocities below the surface of the material,
Sonic anisotropy coefficient, various elastic moduli (Young's modulus, rigidity, bulk modulus, compressibility, Lame parameter), Poisson's ratio, Debye temperature, Grenaizen parameter, longitudinal wave / transverse wave attenuation factor, longitudinal wave / transverse wave internal wear An elastic parameter measuring device for a material surface and a coating layer, which is formed so that the longitudinal and transverse wave frequencies, the linear expansion coefficient and the Nyquist diagram can be measured simultaneously. 2. The sensor is provided with two longitudinal wave / transverse wave simultaneous receivers, and the two longitudinal wave / transverse wave simultaneous receivers are provided at predetermined intervals. 2. The electrodes are juxtaposed on a straight line connecting with
The elastic parameter measuring device for the material surface and coating layer according to. 3. A longitudinal wave / transverse wave simultaneous transmitter and a longitudinal wave.
The transverse wave simultaneous receiver is connected to a pulser / receiver unit that controls the transmission and reception of ultrasonic waves, and this pulser / receiver unit performs A / D conversion to digitally convert the wave received from the longitudinal wave / transverse wave simultaneous receiver side. 3. The elasticity of the material surface and the coating layer according to claim 1 or 2, wherein the A / D converter is connected to a CPU for arithmetic processing having a waveform display function. Parameter measuring device. 4. The CPU is composed of a personal computer, and a pulser / receiver section and an A / D conversion section are incorporated in a board of an integrated circuit thereof. An elastic parameter measuring device for the surface of the material and the coating layer. 5. A longitudinal wave / transverse wave simultaneous transmitter and a longitudinal wave.
The transverse wave simultaneous receiver is composed of two types of piezoelectric domain for longitudinal wave generation and piezoelectric domain for transverse wave generation, and the material surface and coating layer according to any one of claims 1 to 4. Elastic parameter measuring device. 6. The transmission angle and the reception angle are set so that a longitudinal creeping wave and a shear horizontal shear wave propagate simultaneously at a depth of 1 to 5 wavelengths below the surface of the test body. The elastic parameter measuring device for the material surface and the coating layer according to any one of claims 1 to 5. 7. The transmission angle and the reception angle are set such that the sound pressure ratio of the received waveforms of the longitudinal creeping wave and the shear horizontal shear wave is in the range of 1/5 to 5/1. The elastic parameter measuring device for a material surface and a coating layer according to any one of claims 1 to 6. 8. The longitudinal wave / transverse wave simultaneous transmitter and the longitudinal wave.
8. The elastic parameter measuring device for a material surface and a coating layer according to claim 1, wherein the shear wave simultaneous receiver is a piezoelectric element made of ceramics, polymer, or composite of ceramics and polymer. . 9. The elastic parameter measuring device for a material surface and a coating layer according to claim 1, wherein acrylic is used for the wedge member. 10. The material surface according to claim 1, wherein the frequency of the ultrasonic wave transmitted from the longitudinal wave / transverse wave simultaneous transmitter is 0.5 to 100 MHz. Device for measuring elastic parameter of coating layer.