JP3749929B2 - Ultrasonic inspection apparatus and inspection method using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic inspection apparatus used for peeling inspection of a composite material or the like using ultrasonic waves and an inspection method using the ultrasonic inspection apparatus. More specifically, by causing ultrasonic waves to be incident on the test body from the transmitter through the air, generating a plate wave in the test body, and receiving the ultrasonic waves leaking from the test body through the air by the receiver. The present invention relates to an ultrasonic inspection apparatus for inspecting a specimen and an inspection method using the ultrasonic inspection apparatus.
[0002]
[Prior art]
Conventionally, in the peeling inspection of a thin plate, a rolling roll, etc., as in Patent Document 1, a pair of transmitter and receiver are brought into direct contact with the surface of the test body via a contact medium, or the test body and sensor are attached. Techniques such as a water immersion method that submerges and inspects were used.
[0003]
However, in the inspection of plastic composite materials (FRP) such as glass fibers, carbon fibers, and aramid fibers, if a contact medium is applied to the surface of these composite materials or the composite materials are immersed in water, the composite There was a problem of causing a decrease in strength due to liquid intrusion into the material.
[0004]
In addition, the surface of the specimen is scanned by a probe having a pair of transmitter and receiver that has been conventionally used. In this case, since the propagation direction of the plate wave propagating in the specimen is only one direction, there is a limit to improving the detection accuracy of the position, shape and dimensions of the peeled portion even if the scanning pitch is set finely. It was.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-236114 [0006]
[Problems to be solved by the invention]
In view of such a conventional situation, the present invention provides an ultrasonic wave that can quickly and accurately identify defects such as delamination found in a composite material without immersing the specimen in water or applying a contact medium. An object is to provide an inspection apparatus and an inspection method using the ultrasonic inspection apparatus.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the ultrasonic inspection apparatus according to the present invention has a characteristic configuration in which ultrasonic waves are incident on a test body through air from a transmitter to generate a plate wave on the test body, and A test body is inspected by receiving ultrasonic waves leaked from the receiver through air, and at least two pairs of the transmitter and the receiver are arranged, and the transmitter / receiver forming the pair The line segments connecting each other are arranged so as to intersect with each other in plan view, and provided with a scanning device for scanning the transmitter and the receiver along the surface of the test body, and each reception received by the plurality of receivers. For the signal, one feature amount is extracted based on each received signal for each coordinate position, and is displayed as a composite image on the coordinate plane. Here, “one feature value is extracted based on each received signal for each coordinate position” means that, for example, feature values such as a maximum value and a minimum value are extracted from signal values of different receivers in each part. To do.
[0008]
The plurality of transmitters and receivers may be arranged on substantially the same circumference with a point where the line segments intersect each other as a center. Furthermore, it is preferable to arrange the transmitter / receiver so that the line segments connecting the paired transmitter / receiver are sequentially equiangular. Here, “a line segment that connects a pair of transmitters and receivers” refers to a line segment that connects a pair of transmitters and receivers facing each other in a plan view.
[0009]
In addition to the above characteristic configuration, a first storage unit that stores all of the plurality of transmitters and a second storage unit that stores all of the plurality of receivers are provided, and the first storage unit and the first storage unit An acoustic isolation wall may be provided between the two storage units. According to the characteristic configuration, crosstalk between adjacent transmitters and receivers can be prevented.
[0011]
In any one of the above-described features, it is desirable that the ultrasonic wave is a burst wave. According to the same feature, by using a burst wave formed by repeating a plurality of waves, an ultrasonic wave can be reliably incident on the test body, and a plate wave can be efficiently generated on the test body.
[0013]
This is particularly useful when the specimen is a composite material or a multilayer structure. Here, the multilayer structure means a structure formed by joining a plurality of members.
[0014]
A characteristic of the inspection method according to the present invention is an inspection method using the ultrasonic inspection apparatus having any one of the above-described characteristic configurations, in which ultrasonic waves are incident on the test body through air from the transmitter, and the test body In addition to generating a plate wave, the ultrasonic wave leaking from the inside of the test body is received by the receiver through the air, and peeling inside the test body is inspected from a change in amplitude of the received signal.
[0015]
【The invention's effect】
As described above, according to the features of the ultrasonic inspection apparatus according to the present invention and the inspection method using the ultrasonic inspection apparatus, the plane position of the defect can be specified more accurately by combining signals from two or more directions. became. As a result, it is possible to quickly and accurately detect the position, shape, and dimensions of defects such as delamination that have occurred inside the specimen without damaging the strength of the specimen, which can contribute to improved inspection efficiency. It was.
[0016]
Other objects, configurations, and effects of the present invention will become apparent in the following “Embodiments of the Invention” section.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Next, a first embodiment of the present invention will be described with reference to the accompanying drawings.
In the present embodiment, as shown in FIGS. 2 and 4, the test body 100 is sandwiched between the front and back surfaces of a reinforcing material made of a foam core with a composite material 101 made of carbon reinforced fiber resin (CFRP). The case where the position, shape, dimension, etc. of the peeled portion generated on the joint surface between the CFRP 101 and the foam core 102 is detected will be described as an example.
[0018]
As shown in FIG. 1, an ultrasonic inspection apparatus 1 according to the present invention generally includes a sensor unit 10 that houses a transmitter 30 and a receiver 40 having the same structure as each other, and the sensor unit 10 is placed on a specimen surface 100a. The scanning unit 20 is configured to move along, a drive unit 60 for driving them, an operation / signal processing unit 70, and a display 80. The operation / signal processing unit 70 incorporates software for realizing a specific function. By the operation / signal processing unit 70, ultrasonic waves are transmitted / received by the transmitter 30 and the receiver 40 via the drive unit 60. The received waveform is processed by the operation / signal processing unit 70, and the processing result is displayed on the display 80.
[0019]
The previous drive unit 60 includes a function generator 61 for transmitting ultrasonic waves from each transmitter 30 constituting the ultrasonic inspection apparatus 1 and a plurality of amplifying ultrasonic waves received by the plurality of receivers 40. A preamplifier 62 and a motor driver 65 for driving the drive motors M1 to M3 of the scanning unit 20 are provided. In the present embodiment, the function generator 61 is connected to the first to fourth transmitters 30a to 30d, respectively, and the preamplifier 62 is connected to the first to fourth receivers 40a to 40d by the first to fourth function generators 61a to 61d. The first to fourth preamplifiers 62a to 62d connected to the first and fourth preamplifiers 62a to 62d, respectively.
[0020]
As shown in FIG. 2, the scanning unit 20 is generally composed of a specimen storage box 24 and a scanning mechanism 25 for scanning the sensor unit 10. In this scanning mechanism 25, a pair of Y-axis guides 25a, 25a oriented in the direction perpendicular to the drawing sheet is placed, and the pair of Y-axis sliders 25b, 25b are driven by a first drive motor M1 (not shown). It slides on each Y-axis guide 25a. In addition, the X-axis slider 25d slides along the single X-axis guide 25c straddling the pair of Y-axis sliders 25b and 25b by the driving of the second drive motor M2. The sensor unit 10 supported by the support rod 26 by the Z-axis slider 25f is driven in the Z-axis direction by the third driving motor M3 along the Z-axis guide 25e provided on the X-axis slider 25d.
[0021]
In this embodiment, the flat test body 100 is placed on a substantially horizontal mounting table 24 a on the bottom surface of the test body storage box 24. The previous Y-axis guide 25a and X-axis guide 25c are placed in parallel with the surface of the test specimen 100a or the mounting table 24a. For example, scanning is performed along a path R shown in FIG. 5 while maintaining substantially parallel to the upper surfaces of the test body 100 and the mounting table 24a.
[0022]
The motor controller 72 in the operation / signal processing unit 70 is activated by an input from a control device 73 such as a keyboard. The transmission time, period, and phase of the burst voltage signals generated from the function generators 61a to 61d via the delay device 63 can be made different from each other. In the present embodiment, the delay device 63 has a delay circuit corresponding to each channel individually. Instead of providing the delay circuit, the delay device 63 can be configured to individually change the transmission time of the ultrasonic wave for each channel according to an instruction from the control device 73.
[0023]
The motor controller 72 drives the drive motors M <b> 1 to M <b> 3 via the motor driver 65 and sends the coordinate signals to the processing device 76.
[0024]
The signals received by the preamplifiers 62a to 62d are digitized by the A / D converter 64 for each channel, and then processed by the processing unit 76 for each channel together with the coordinate signal. As shown in FIG. 8, it is displayed on the display unit 80 by color tone display.
[0025]
Next, the configuration of the ultrasonic sensor unit 10 will be described. As shown in FIGS. 3 and 4, the ultrasonic sensor unit 10 has a top plate in a storage chamber 11 surrounded by a top plate 15 having a circular shape in a plan view and a side wall 16 hanging from the periphery of the top plate 15. Four pairs of transmitters 30 and receivers 40 having the same configuration are attached by eight probe support rods 17a to 17h suspended from 15 respectively. Then, ultrasonic waves are transmitted and received between the transmitter 30 and the receiver 40 that make a pair, thereby generating a plate wave in the test body 100, peeling inside the composite material 101, and the composite material 101 and the foam core 102. Detects peeling at the joint surface.
[0026]
As shown in FIGS. 3 and 4, the storage chamber 11 inside the sensor unit 10 is separated into a first storage portion 11 a and a second storage portion 11 b by an acoustic isolation wall 13. The plurality of transmitters 30a to 30d and receivers 40a to 40d are arranged symmetrically with respect to the center point C of the sensor unit with respect to the center point C of the sensor unit. To do. That is, when the transmission / reception axis of each transmitter 30 and receiver 40 is projected onto the specimen surface 100a, the projected line segments L1 to L4 are arranged so as to intersect each other at the center point C. It is also an intersection. At that time, the angles B1 to B8 formed between adjacent transmission / reception are all equal angles of about 45 °.
[0027]
All the ultrasonic waves transmitted from the transmitters 30a to 30d pass directly below the center point C, and are received only by the receivers 40a to 40d at symmetrical positions with the center point C in between. In the present embodiment, the first transmitter 30a and the first receiver 40a, the second transmitter 30b and the second receiver 40b, the third transmitter 30a and the third receiver 40c, and the fourth transmitter 30d. The fourth receiver 40d corresponds to a transmitter / receiver paired with each other.
[0028]
The acoustic isolation wall 13 is for preventing the ultrasonic signal transmitted from the adjacent transmitter from being received by the adjacent receiver (crosstalk). In the present embodiment, the first transmitter 30a and the fourth receiver 40d, and the fourth transmitter 30d and the first receiver 40d correspond to adjacent transmitter / receivers.
[0029]
Each transmitter 30 generally includes a transmitter main body 31 including a vibrator 32, a support arm 57 for attaching the transmitter main body 31 to the transmitter support column 17, and an inclination for adjusting the inclination of the transmitter main body 31. And an adjustment mechanism 55. Further, the vibrator 32 is vibrated by the burst voltage signal from the drive unit 60 via the cable 33, and ultrasonic waves are transmitted toward the test body 100. In the present embodiment, in this vibrator 32, directivity is imparted to the ultrasonic wave incident on the test body 100 by ensuring a sufficient width of the transmission surface.
[0030]
The inclination adjustment mechanism 55 is configured to lock the pin tip 56a of the spring lock pin 56 on the inclination adjustment surface 54a of the inclination adjustment plate 54 attached to the side surface of the transmitter body 31. Specifically, the inclination angle θ given by the angle formed by the transmitter mounting center axis F and the normal line G of the specimen surface 100a can be appropriately adjusted by adjusting the pressing force by the spring 56b with the inclination adjustment knob 56c. As a variable transmitter. According to experiments by the inventors, it has been found that an angle in the vicinity of about 14 degrees is appropriate as the inclination angle θ in order to generate a plate wave in a CFRP having a thickness of 6 mm. Note that the tilt angles θ of the other transmitters and receivers are all adjusted to the same angle.
[0031]
Next, an inspection procedure using the ultrasonic inspection apparatus 1 according to the present invention will be described. First, the sensor unit 10 is arranged so that the sensor unit 10 is parallel to the specimen surface 100a. The drive motors M1 to M3 are driven, and the sensor unit 10 is moved at predetermined pitch intervals along the specimen surface 100a as shown in the path R shown in FIG. The scan and step interval in the XY direction is about 1/100 to 1/200 of the distance E between the incident and receiving points shown in FIG. Then, at each coordinate position, an ultrasonic wave is transmitted simultaneously from each transmitter.
[0032]
For each received signal received by the receivers 40a to 40d, the maximum amplitude value within the time width (gate) synchronized with the repetition frequency of the received burst wave is extracted. Then, from the received data obtained for each transmitter-receiver position shown in FIGS. 6A to 6D, the maximum amplitude value obtained for each scanning position is displayed in color tone on the scanning map. C-scan images as shown in FIGS. 7A to 7D can be obtained.
[0033]
If there is a peeling portion in the propagation path of the plate wave, the maximum amplitude value at the coordinate position is a value reflecting the influence of the peeling portion. That is, if there is a separation part in the propagation path, the plate wave attenuates at the separation part, so that the amplitude value is relatively lower than the signal that has passed through only the healthy part. For this reason, the maximum amplitude value of the coordinate position is lower than the maximum amplitude value of other portions.
[0034]
In this way, depending on the position of the paired transmitter / receiver, there may be a case where there is a peeling portion in the propagation path of the plate wave and a case where it does not exist. As shown in FIGS. 7A to 7D, in the C scan image for each receiver 40a to 40d, an elongated low-amplitude region along the traveling direction of the plate wave is observed.
[0035]
8 extracts the maximum value for each coordinate position from the maximum amplitude values for each of the receivers 40a to 40d shown in FIGS. 7A to 7D, and displays the extracted color on the coordinate plane. It is a thing. For example, if only a part of FIGS. 7A to 7D is at a coordinate position indicating a low amplitude value, the synthesized image shown in FIG. 8 is displayed as a healthy part having a high amplitude value. On the other hand, in any C-scan image, at a coordinate position displayed as a peeling portion with a low amplitude value, it is displayed as a peeling portion with a low amplitude value in the composite image. That is, in this composite image, a low amplitude value is shown only when a peeling portion exists in the vicinity immediately below the target coordinates. Therefore, as in the present embodiment, the composite image obtained as a result of the inspection on the test body 100 having a circular peeled portion in a plan view is displayed as a circular amplitude distribution with the peeled portion center as a minimum value. It becomes.
[0036]
Next, the propagation characteristics of the plate wave when detecting the peeling inside the test body 100 using the ultrasonic inspection apparatus 1 according to the present invention will be briefly described. The ultrasonic waves transmitted from the plurality of transmitters 30 a to 30 d are incident on the inside of the test body 100 through the air that is an acoustic coupling medium, and generate a plate wave in the test body 100. Since the plate wave propagates through the specimen 100 while leaking a part of the plate wave to the outside, the leaked ultrasonic waves are respectively received by the receivers 40a to 40d through the air that is the acoustic coupling medium, and the received signal The peeling in the specimen 100 is detected from the amplitude. At this time, if a separation portion exists in the propagation path of the plate wave, the plate wave is attenuated or amplified in the separation portion.
[0037]
For example, when there is a peeling portion at the boundary surface between the composite material and the hard lining material or inside the composite material, the plate wave is generally attenuated because the propagation condition of the plate wave changes in the peeling portion. On the other hand, when there is a separation that occurs between the composite material and the soft lining material, the component leaking to the soft lining material is reduced, so the amplitude of the plate wave is relatively less than when there is no separation. growing. Therefore, by observing the change in the reception amplitude of the ultrasonic wave received by the receiver 40, it is possible to detect the peeling inside the test body 100.
[0038]
【Example】
In order to demonstrate that the ultrasonic inspection apparatus 1 according to the present invention is useful for peeling inspection of a composite material or the like, the inventors have made a test specimen 100 having artificial peelings D1 to D4 as shown in FIG. A peel test was conducted. The test body 100 is a flat plate having a two-layer structure of a lining material made of CFPR having a thickness of 6 mm and rubber having a thickness of 2 mm, and has first to fourth artificial peelings D1 to D4 on the boundary surface between the CFRP and the lining material. A thing was used. Here, the first artificial peeling D1 was 20 mm in diameter, the second artificial peeling D2 was 11 mm in diameter, the third artificial peeling D3 was 10 mm in diameter, and the fourth artificial peeling D4 was 16 mm in diameter. Further, the inclination angle θ of the transmitter 30 and the receiver 40 is adjusted so that the distance E between the incident and receiving points of the ultrasonic wave is 55 mm, and the distance H between the transmitter 30 and the receiver 40 and the specimen surface 100a is 5 mm. did.
[0039]
When performing the scanning, the ultrasonic sensor unit 10 was moved so as to be parallel to the specimen surface 100a as shown by a path R shown in FIG. At that time, the pitch interval in the scanning direction X was set to 0.5 mm, and the pitch interval in the step direction Y was set to 0.5 mm.
[0040]
In this embodiment, data collection was performed for each pair of the transmitter 30 and the receiver 40 as shown in FIGS. 6A to 6D at each coordinate position. FIGS. 7A to 7D show the maximum amplitude value of the received signal obtained as a result of the scanning shown in FIGS. 6A to 6D in color tone display (C scan image) for each coordinate position. FIG. 8 shows the color tone of the extracted maximum values for each coordinate position among the maximum amplitudes of these four received waves. It was confirmed that the amplitude value distribution of the composite image shown in FIG. 8 matched the actual peeling shapes of the artificial peelings D1 to D4 with high accuracy.
[0041]
Finally, the possibility of other embodiments of the ultrasonic inspection apparatus according to the present invention will be mentioned. In addition, you may implement combining each embodiment shown below suitably.
In the above embodiment, CFRP is described as an example of the composite material, but a composite material other than CFRP may be used. Further, the present invention is not necessarily limited to the composite material, and can be applied to peel inspection of various low density thin plates.
[0042]
In the above-described embodiment, the case where the separation on the joint surface of the test body 100 having the multilayer structure is detected has been described as an example. However, it is also possible to detect a defect in the inspection target material.
[0043]
Moreover, in the said embodiment, the flat thing was used as the test body 100. FIG. However, for example, the present invention can be applied not only to a flat plate-like material such as a composite member attached to an outer wall of an aircraft, an automobile, a rocket, an artificial satellite, or the like, but also to various shapes whose surfaces are bent.
[0044]
In the said embodiment, the case where the acoustic isolation wall 13 was provided so that the 1st accommodating part 11a and the 2nd accommodating part 11b were completely divided into 2 was demonstrated as an example. However, if it is possible to prevent crosstalk between transmitters and receivers, not only when the storage unit 11 is completely divided into two parts, but also when, for example, it is provided only in the vicinity of adjacent transmitters and receivers, It is also possible to provide only at the center.
[0045]
In the above embodiment, the case where the acoustic isolation wall 13 is provided has been described as an example. However, if transmission times are appropriately changed for each of the transmitters 30a to 30d, interference between ultrasonic waves does not occur, and crosstalk between adjacent transmitters and receivers can be prevented without providing the acoustic isolation wall 13. For example, in the sensor unit 10 shown in FIG. 3, first, ultrasonic waves are transmitted simultaneously from the first transmitter 30a and the third transmitter 30c. Thereafter, ultrasonic waves may be transmitted simultaneously from the second transmitter 30b and the fourth transmitter 30d. In this case, no ultrasonic wave is transmitted from the adjacent fourth transmitter 30d when receiving by the first receiver 40a, and similarly, the first transmission adjacent when receiving by the fourth receiver 40d. No ultrasonic wave is transmitted from the child 30a. Therefore, the problem of crosstalk does not occur between these adjacent transceivers.
[0046]
In the above embodiment, when the low-intensity part of the received signal corresponds to a defective part, and the received signals at all angles at a certain position are still low-intensity, the combining process is performed with that part as the defective part. However, depending on the nature of the defect, if the high-strength part of the received signal corresponds to the defective part and the received signal at all angles at a certain position is high-intensity, the synthesis process is performed with that part as the defective part. Is also possible. In addition to obtaining the maximum amplitude of the received signal, it is also possible to obtain an average amplitude and an integral value and perform each signal processing based on this.
[0047]
In addition, the code | symbol entered in the term of the claim is only for the convenience of contrast with drawing, and this invention is not limited to the structure of an accompanying drawing by this entry.
[Brief description of the drawings]
FIG. 1 is a block diagram of an inspection apparatus including an ultrasonic inspection apparatus according to the present invention.
FIG. 2 is a sectional view of a scanning unit.
FIG. 3 is a plan view of the inside of the sensor unit.
4 is a cross-sectional view taken along line AA in FIG.
FIG. 5 is a diagram showing a relationship between a scanning direction by a sensor unit and an artificial peeling position provided on a specimen.
FIG. 6 is a diagram showing a positional relationship between a transmitter and a receiver used in scanning performed using the ultrasonic inspection apparatus according to the present invention.
7A to 7D are C-scan images obtained by performing scanning in the inspection arrangements shown in FIGS. 5A to 5D, respectively.
FIG. 8 is a composite image obtained from the C-scan image shown in FIGS.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1: Ultrasonic inspection apparatus, 10: Sensor unit, 11: Storage chamber, 11a: 1st storage part, 11b: 2nd storage part, 13: Acoustic isolation wall, 15: Top plate, 16: Side wall, 17, 17a- h: transceiver support column, 20: scanning unit, 24: specimen storage box, 24a: mounting table, 25: scanning device, 25a: Y-axis guide, 25b: Y-axis slider, 25c: X-axis guide, 25d: X Axis slider, 25e: Z-axis guide, 25f: Z-axis slider, 25g: Transmitting unit support rod, 30: Transmitter, 30a to d: First to fourth transmitters, 31: Transmitter body, 32: Vibrator 33: Cable, 40: Receiver, 40a to d: First to fourth receiver, 41: Transmitter body, 42: Vibrator, 43: Cable, 53: Transceiver support block, 54: Tilt adjusting plate, 54a: inclination adjustment surface, 55 Inclination adjustment mechanism, 56: Spring lock pin, 56a: Pin tip, 56b: Spring, 56c: Inclination adjustment knob, 57a to f: First to eighth support arms, 60: Drive unit, 61: Function generator, 61a to d : First to fourth function generators, 62: preamplifier, 62a to d: first to fourth preamplifiers, 63: delay device, 64: A / D converter, 65: motor driver, 70: operation / signal processing unit, 72 : Motor controller, 73: Control device, 76: Processing device, 80: Display, S: Test specimen, 101: Composite member (CFRP), 102: Reinforcement material (foam core), D1-4: Artificial peeling, E: Distance between incident and receiving points, F: Transmitter / receiver mounting center axis, G: Normal, H: Distance between transmitter and receiver surface, M1 to M3: Drive Motor, X: the scanning direction, Y: stepping direction, theta: the tilt angle

Claims (7)

  Ultrasonic waves are incident on the test body (100) from the transmitter (30) via air to generate a plate wave on the test body (100), and the ultrasonic waves leaked from the test body (100) are air. An ultrasonic inspection apparatus for inspecting a test body (100) by receiving at a receiver (40) via an antenna, wherein at least two pairs of the transmitter (30) and receiver (40) are arranged. The line segments (L1 to L4) connecting the paired transceivers (30a to d, 40a to d) intersect with each other in plan view, and the transmitter (30) and the receiver ( 40) is provided with a scanning device (20) for scanning along the surface of the test body (100a), and the received signals received by the plurality of receivers (40a to 40d) Extract one feature based on the coordinate plane An ultrasonic inspection apparatus comprising a signal processing device (76) capable of being displayed as a composite image on a surface.   The plurality of transmitters (30a to d) and receivers (40a to d) are arranged on substantially the same circumference with a point where the line segments (L1 to L4) intersect with each other as a center. The ultrasonic inspection apparatus according to 1.   The ultrasonic inspection apparatus according to claim 1 or 2, wherein the transceivers (30a to d, 40a to d) are arranged so that the line segments (L1 to L4) are equiangular in order.   A first storage part (11a) for storing all of the plurality of transmitters (30a to d) and a second storage part (11b) for storing all of the plurality of receivers (40a to d); The ultrasonic inspection apparatus according to any one of claims 1 to 3, wherein an acoustic isolation wall (13) is provided between the first storage part (11a) and the second storage part (11b).   The ultrasonic inspection apparatus according to claim 1, wherein the ultrasonic wave is a burst wave.   6. The ultrasonic inspection apparatus according to claim 1, wherein the test body (100) is a composite material (101) or a multilayer structure (101, 102).   It is an inspection method using the ultrasonic inspection apparatus according to any one of claims 1 to 6, wherein ultrasonic waves are incident on the test body via air from a transmitter (30), and the test body (100) While generating a plate wave, the ultrasonic wave leaked from the inside of the test body (100) is received by the receiver (40) through the air, and the peeling inside the test body (100) is inspected from the change in the amplitude of the received signal. Inspection method characterized by that.

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