JP4630992B2 - Ultrasonic inspection method and ultrasonic inspection apparatus used therefor - Google Patents

Description

  The present invention relates to an ultrasonic inspection method and an ultrasonic inspection apparatus used therefor. More specifically, an ultrasonic wave is incident on the test body from the transmitter, a plate wave is generated on the test body, and the ultrasonic wave leaking from the test body is received by the receiver so that the test body is inspected. The present invention relates to an ultrasonic inspection method and an ultrasonic inspection apparatus used therefor.

  2. Description of the Related Art Conventionally, a tapping test (sound hit test) has been performed as a method for inspecting the adhesion interface of different materials. However, because it is a sensory test that is an auditory test, it is easily affected by the physical condition of the inspector and surrounding noise, so the evaluation is not objective, and the recording method is used to manually mark the location where abnormal noise occurs due to tapping. The management of records is analog, and the storage and management of records is complicated.

  As a peeling inspection method using ultrasonic waves, as shown in FIG. 11, a vertical reflection method is generally performed in which ultrasonic waves are incident perpendicularly to the interface and evaluation is performed based on the magnitude of the reflected signal intensity from the interface. Yes. However, as shown in FIG. 11A, for example, when the heat insulating material 101 ′ is an ultrasonic high attenuation material, it enters from the outer surface side, passes through the heat insulating material 101 ′, reaches the thin plate 102 ′, and is reflected there. Then, the ultrasonic component A that passes through the heat insulating material 101 ′ again and reaches the sensor 200 on the outer surface side, the ultrasonic component B from the bottom surface of the thin plate 102 ′, and the reflection signal C at the defect (peeling) D ′ are all very Therefore, it was difficult to evaluate the adhesion state of the interface between the heat insulating material 101 ′ and the thin plate 102 ′.

  As an ultrasonic inspection of high-attenuation materials, in general, inspection is performed by lowering the frequency of ultrasonic waves in order to reduce the influence of ultrasonic attenuation. However, as shown in FIG. 11 (b), the wavelength becomes longer, and it becomes difficult to separate the signal A from the interface between the thin plate 102 ′ and the heat insulating material 101 ′ and the signal B from the bottom surface of the thin plate 102 ′, resulting in a defect (peeling) D. Since the difference from the reflected signal C at 'does not appear clearly, it was difficult to evaluate the peeling based on the signal strength at the interface. Further, in the vertical reflection method, the reflection signal from the defect D ′ cannot be detected unless the defect D ′ at the interface between the thin plate 102 ′ and the heat insulating material 101 ′ has a gap. For this reason, it is difficult to detect a defect in which a gap is not formed by contact between the thin plate 102 ′ and the heat insulating material 101 ′ even if the defect D ′ exists at the interface.

  As other inspection methods, for example, the inspection methods described in Patent Documents 1 and 2 are known. In the inspection method described in Patent Document 1, a sensor head is configured by arranging a plurality of pairs of transmitters and receivers sandwiching a center point, and a feature amount of a received signal received by each receiver is determined for each scanning position. To generate a composite image. Therefore, the structure is complicated and the image processing is complicated.

Moreover, in the inspection method described in Patent Document 2, a transmitter and a receiver are provided on one side of a test body, and a defective portion of the test body is inspected by a reflected wave. However, when the test specimen is a thin plate, it was difficult to evaluate the peeling of the interface as in the case of the vertical reflection method described above.
Japanese Patent No. 3749929 JP 2006-138818 A

  In view of such conventional circumstances, the present invention can detect defects such as interface peeling quickly and accurately even in a multilayer structure including a thin member such as a thin plate with a simple configuration. An object is to provide a possible ultrasonic inspection method and an ultrasonic inspection apparatus used therefor.

  In order to achieve the above object, the ultrasonic inspection method according to the present invention is characterized in that an ultrasonic wave is incident on a test body from a transmitter, a plate wave is generated on the test body, and an ultrasonic wave leaks from the test body. In the method of inspecting the test body by receiving the signal with the receiver, the test body is located on the incident side of the ultrasonic wave, the first member capable of transmitting the ultrasonic wave, and the second member capable of transmitting the plate wave The first member is made of a high-attenuation material of ultrasonic waves, and the ultrasonic waves are ultrasonic waves in a low frequency band so as to reduce attenuation in the test body. The ultrasonic wave is incident from the first member to generate a plate wave on the second member, and a leakage wave generated from the plate wave propagated through the second member is received, and the transmission is performed according to the amplitude of the received signal. In the direction of ultrasound transmission / reception Serial is to detect defects present between the transmission element or the receivers second member.

  The ultrasonic wave propagating from the transmitter to the receiver through the inside of the test body has a significantly reduced propagation efficiency due to defects existing in the propagation path, and the signal strength of the received signal received by the receiver is reduced. Become. Therefore, by receiving the ultrasonic wave after propagating through the second member, it is possible to reliably detect a defect existing between the transmitter or the receiver and the second member based on the amplitude of the received signal. it can. Furthermore, by using a plate wave that propagates while vibrating the entire member, even if there is a defect in which the thin plate is in contact with the heat insulating material and no gap is formed, the in-plane restraint force is caused by the propagation of the plate wave. Since the gap is opened, a gap is generated in the defect. Therefore, even a defect in which no gap is formed can be reliably detected, and the adhesion state of the first and second members can be evaluated.

  Moreover, it is desirable that the transmitter and the receiver transmit and receive the ultrasonic waves to and from the test body via gas. It is desirable that the transmitter and the receiver are scanned along the surface of the specimen.

In order to achieve the above object, the ultrasonic inspection apparatus used in the ultrasonic inspection method according to any one of the above is characterized in that the test body is located on an ultrasonic incident side and the first member is capable of transmitting ultrasonic waves. And at least a second member capable of propagating a plate wave. The first member is made of a high-attenuation material of ultrasonic waves, and the ultrasonic waves are attenuated by the test body. It is an ultrasonic wave in a low frequency band so as to reduce, and the ultrasonic wave is incident on the second member to generate a plate wave on the second member, and a leaky wave generated from the plate wave propagated through the second member The object is to detect defects in the first member or in the interface between the first member and the second member in the transmission / reception direction of the ultrasonic waves of the transmitter or the receiver based on the amplitude of the received signal.

  According to the characteristics of the ultrasonic inspection method according to the present invention and the ultrasonic inspection apparatus used therefor, even in a multilayer structure including a thin member such as a thin plate with a simple configuration, peeling of the interface, etc. This makes it possible to quickly and accurately detect defects.

  Other objects, configurations, and effects of the present invention will become apparent from the following embodiments of the present 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 3, as the test body 100, the thin plate 102 made of aluminum serving as the second member is positioned on the front and back of the honeycomb structure 103 made of aluminum, and the first member and The thing with which the heat insulating material 101 which becomes is applied is used. The multilayer structure having such a structure is used, for example, for the exterior of a satellite fairing part of a rocket. The case where the position, shape, dimension, etc. of the peeled portion generated on the joint surface between the heat insulating material 101 and the thin plate 102 is detected will be described as an example.

  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. It comprises a scanning unit 20 for moving along, a drive unit 60 for driving them, an operation / signal processing unit 70, and a display 77. 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. Then, the received waveform is processed by the operation / signal processing unit 70, and the processing result is displayed on the display 77.

  The previous drive unit 60 includes a function generator 61 for transmitting ultrasonic waves from the transmitter 30 constituting the ultrasonic inspection apparatus 1, a preamplifier 62 for amplifying the ultrasonic waves received by the receiver 40, and scanning. A motor driver 65 for driving the drive motors M1 to M3 of the unit 20 is provided.

  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.

  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. 7 while maintaining substantially parallel to the upper surfaces of the test body 100 and the mounting table 24a.

  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 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.

  The signal received by the preamplifier 62 is digitized by the A / D converter 64 and then subjected to signal processing together with the coordinate signal by the processing device 76, and the analysis result is displayed on the display 77 by color tone display as shown in FIG. .

  Next, the configuration of the ultrasonic sensor unit 10 will be described. As shown in FIG. 3, the ultrasonic sensor unit 10 includes two pieces suspended from the top plate 15 in a storage chamber 11 surrounded by the top plate 15 and a side wall 16 hanging from the periphery of the top plate 15. A pair of transmitters 30 and receivers 40 having the same structure are attached by probe support columns 17a and 17b. A first adjustment screw 18 for adjusting the inclination of the transmitter 30 and the receiver 40 at the same time is attached to the top plate 15. An isosceles triangular abutting portion 19 with which the adjusting screw 52 abuts is provided. Then, by transmitting and receiving ultrasonic waves between the transmitter 30 and the receiver 40 that make a pair, a plate wave is generated in the thin plate 102 in the test body 100, and defects inside the heat insulating material 101 and the heat insulating material 101 The peeling at the joint surface with the thin plate 102 is detected.

  The transmitter 30 and the receiver 40 are arranged symmetrically with respect to the center line of the sensor unit 10 in a plan view. The ultrasonic wave transmitted from the transmitter 30 passes directly under the center line and is received by the receiver 40 at a symmetrical position across the center line.

  The transmitter 30 generally includes a transmitter body 31 including a vibrator 32, a support arm 53 for rotatably mounting the transmitter body 31 to the transmitter support column 17a, and adjusting the inclination of the transmitter body 31. And an inclination adjusting mechanism 50. 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.

  The inclination adjustment mechanism 50 is composed of a support plate 51 attached to the side surface of the transmitter body 31 and a second adjustment screw 52 at the tip thereof, and the tip of the second adjustment screw 52 is brought into contact with the inclined surface 19a of the contact portion 19. And Specifically, the inclination of the transmitter 30 is adjusted by simultaneously adjusting the inclination of the transmitter 30 and the receiver 40 by the first adjustment screw 18 and finely adjusting the inclination of the transmitter 30 by the second adjustment screw 52. Thus, the variable transmitter is configured such that the inclination angle θ given by the angle formed by the transmitter attachment center axis F and the normal line G of the specimen surface 100a can be adjusted as appropriate. The inclination angle θ of the receiver is also adjusted to the same angle.

  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 along the specimen surface 100a at predetermined pitch intervals as shown in the path R shown in FIG. Then, ultrasonic waves are transmitted from the transmitter at each coordinate position. In this embodiment, since the heat insulating material 101 is a high attenuation material, ultrasonic waves in a low frequency band are transmitted to reduce the influence of attenuation. Even in the case of ultrasonic waves in the low frequency band, the defect is evaluated based on the amplitude of the ultrasonic waves propagated through the thin plate 102 by the plate wave. Therefore, even if the time resolution is low and the time resolution is low, the evaluation accuracy is not affected.

  Then, in the reception signal received by the receiver 40, the maximum amplitude value within the time width (gate) of the ultrasonic wave propagation time is extracted for each coordinate position of the sensor unit 10. Then, from the received data obtained for each transmitter-receiver position, the maximum amplitude value obtained for each scanning position is displayed in color on the scanning map, thereby obtaining a C-scan image as shown in FIG. be able to.

  Here, with reference to FIGS. 4 to 6, the propagation of the ultrasonic wave between the transmitter and the receiver when the peeling inside the specimen 100 is detected using the ultrasonic inspection apparatus 1 according to the present invention will be described.

  As shown in FIG. 4A, in the sound part, the ultrasonic wave transmitted from the transmitter 30 is incident on the inside of the test body 100 through the air which is an acoustic coupling medium, passes through the heat insulating material 101, and is a thin plate 102. A plate wave is generated. The plate wave propagates in the thin plate 102 while part of the plate wave leaks into the heat insulating material 101, and the leaked ultrasonic wave is received as a signal as shown in FIG. 40.

  In order to generate a plate wave in the thin plate 102, 1) the thickness of the thin plate 102, 2) the frequency of the applied ultrasonic wave, 3) the longitudinal wave speed of the thin plate 102, 4) a specific wave speed depending on the longitudinal wave speed in the air. It is necessary to enter at an incident angle. Further, FIG. 6 shows a product FT of an ultrasonic frequency and a plate thickness T of the specimen 100, and an incident angle θ, for each plate wave mode (symbols A0 to 5, S0 to 5) in the thin plate 102 made of aluminum. It is a graph which shows the relationship. Only when the relationship indicated by each curve is satisfied, a plate wave of a specific mode is generated inside the thin plate 102. According to the experiments by the inventors, in order to generate a plate wave on the thin aluminum plate 102 having a thickness of 0.4 mm, an angle of about 20 degrees is appropriate as the inclination angle θ. It was found to occur.

  However, as shown in FIG. 4B, in the ultrasonic transmission direction of the transmitter 30, the ultrasonic wave transmitted from the transmitter 30 is present when the peeling defect portion D exists at the interface between the heat insulating material 101 and the thin plate 102. Enters the test body 100 through the air, which is an acoustic coupling medium, and passes through the heat insulating material 101. However, since the propagation efficiency of the ultrasonic wave transmitted through the separation defect portion D at the interface is extremely reduced, the plate 102 hardly generates a plate wave. Therefore, the amplitude of the received signal received by the receiver 40 is significantly reduced as shown in FIG.

  In addition, as shown in FIG. 4C, the ultrasonic wave transmitted from the transmitter 30 when the peeling defect portion D exists at the interface between the heat insulating material 101 and the thin plate 102 in the ultrasonic wave receiving direction of the receiver 40. Enters the test body 100 through the air, which is an acoustic coupling medium, passes through the heat insulating material 101, and generates a plate wave on the thin plate 102. The plate wave propagates through the thin plate 102 while part of the plate wave leaks into the heat insulating material 101. However, since the leaked ultrasonic wave has an extremely low propagation efficiency to the heat insulating material 101 due to the separation defect at the interface, the amplitude of the received signal received by the receiver 40 is similar to that shown in FIG. c) Remarkably reduced as shown in FIG.

  On the other hand, as shown in FIG. 4D, when a peeling defect D exists at the interface between the heat insulating material 101 and the thin plate 102 on the propagation path of the plate wave, the plate wave generated in the thin plate 102 leaks during propagation. The leaking wave is reduced in its leakage component because the propagation efficiency to the heat insulating material 101 is extremely lowered by the peeling defect portion D. Therefore, the amplitude of the received signal received by the receiver 40 is equal to or greater than that in the case of the healthy part as shown in FIG.

  As described above, when there is a defective portion D in the transmission / reception direction of the transmitter 30 or the receiver 40, since the propagation of ultrasonic waves is inhibited by the defective portion D, a clear decrease occurs in the amplitude of the received signal, The peeling defect portion D can be clearly detected. Further, by scanning the sensor unit 10 along the specimen surface 100a, two defect indications depending on the distance between the transmitter and the receiver can be obtained for one defect, for example, as shown in FIG. Delamination can be detected. In addition, since two defect instructions depending on the distance between the transmitter and the receiver can be obtained, erroneous determination can be prevented.

  In order to demonstrate that the ultrasonic inspection apparatus 1 according to the present invention is useful for peeling inspection of a multilayer structure, the inventors have made a test specimen 100 having artificial peelings D1 to D6 as shown in FIG. A peel test was conducted. The test body 100 is a multi-layered flat plate of a honeycomb structure 103 covered with a heat insulating material 101 having a thickness of 6 mm and a thin aluminum plate 102 having a thickness of 0.4 mm, and is formed at the interface between the heat insulating material 101 and the thin aluminum plate 102. What has 1st-6th artificial peeling D1-D6 was used. Here, the first artificial peel D1 has a diameter of 17 mm, the second artificial peel D2 has a diameter of 12 mm, the third artificial peel D3 has a diameter of 8 mm, the fourth artificial peel D4 has a diameter of 6 mm, and the fifth artificial peel D5 has a circular shape with a diameter of 3 mm. The sixth artificial exfoliation D6 has a rectangular shape with a length of 30 mm and a width of 100 mm. 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 25 mm, and the distance H between the transmitter 30 and the receiver 40 and the specimen surface 100a is 2 mm. did.

  At the time of scanning, the ultrasonic sensor unit 10 was moved parallel to the specimen surface 100a so that the scanning direction and the arrangement direction of the transmitter 30 and the receiver 40 would be the same direction as the path R shown in FIG. At that time, the pitch interval in the scanning direction X was 1 mm, and the pitch interval in the step direction Y was 1 mm.

  In this embodiment, the receiver 40 collects data of received signals at each coordinate position. 8 extracts the maximum amplitude value in the propagation time width between the transmitter 30 and the receiver 40 of the received signal obtained as a result of the scanning of the path shown in FIG. 7 for each coordinate position, and displays the color tone (C scan image). It is a thing. As shown in FIG. 8, it is confirmed that the amplitude value distribution of the composite image clearly detects the artificial peeling D except for the fifth artificial peeling having a minimum diameter of 3 mm among the actual artificial peelings D1 to D6. It was.

Finally, the possibility of another embodiment of the ultrasonic inspection apparatus according to the present invention will be mentioned. In addition, you may implement combining each embodiment shown below suitably. Moreover, in the following embodiment, the same code | symbol is attached | subjected to the member etc. similar to the said embodiment.
In the above embodiment, the aluminum thin plate and the heat insulating material applied to the thin plate have been described as examples. However, the present invention can also be applied to peeling inspection of various multilayer structures other than this multilayer structure. Furthermore, in the said embodiment, the flat thing was used as the test body 100. FIG. However, the present invention is not limited to a flat plate shape but can be applied to various shapes having a curved surface.

  In the above-described embodiment, the case where the separation at the joint surface between the heat insulating material 101 serving as the first member and the thin plate 102 serving as the second member is detected as an example has been described. It is also possible to detect a defect existing between the first member and the second member.

  In the above embodiment, the maximum amplitude value of the received signal in the ultrasonic propagation time width is extracted. However, it is not limited to the maximum amplitude value, and it is also possible to obtain an average amplitude or an integral value and perform each signal processing based on this.

  In the above embodiment, the scanning direction of the sensor unit 10 and the arrangement direction of the transmitter 30 and the receiver 40 are the same direction. However, the scanning direction may be perpendicular to the arrangement direction. Even in this case, two defect indications depending on the distance between the transmitter and the receiver can be obtained for one defect by scanning the entire specimen.

  In the above embodiment, the transmitter 30 and the receiver 40 are attached to the sensor unit 10, and the scanning unit 20 scans the specimen surface 100 a in a non-contact manner. However, the transmitter 30 and the receiver 40 may be configured to be able to scan the test body 100 in a non-contact manner. For example, as shown in FIG. 9, the transmitter 30 and the receiver 40 are respectively attached to a casing 85 provided with wheels 86b at four corners, and are supported with respect to the support frame 81 via a swing mechanism 84 that can swing them. Alternatively, a sensor unit 80 configured so as to be movable in the vertical direction may be used. Thereby, the angle with respect to the test body surface of a transmitter and a receiver can be kept constant, and a defect can be detected more suitably with respect to various shapes in which the test body surface is bent.

  In the above embodiment, the planar vibrators 32 and 42 are used for the transmitter 30 and the receiver 40. However, the transducer is not limited to a planar transducer, and for example, a focus type probe having a curved transducer may be used. In this case, as shown in FIG. 10, the bending direction (swing direction axis along the direction in which the reference axis Q along the ultrasonic wave propagation path is swung around the focus P of the probe) is focused on L1. The propagation part surface L2 including the surface of the test body 100 of the propagation part near P is crossed. With such an arrangement, as shown by the arrows, the incident angle θ (and the receivable angle) can take a plurality of states with reference to the incident angle θ = θ0 of the central axis.

  Further, the shapes of the transmitter and the receiver are not limited to the focus type probe having the above configuration. For example, a concave acoustic lens may be provided on the emission surface from the transmitter using a plane transducer, or a focal probe may be configured using a concave transducer. Further, a sensor array transducer may be employed. Further, by using a plane vibrator, a convex acoustic lens is provided on the emission surface from the transmitter, or by using the convex vibrator to diffuse ultrasonic waves from the transmitter, the incident angle θ is It is possible to obtain a plurality. However, the focus type is desirable from the viewpoint of securing sound pressure.

  In the above embodiment, the transmitter and the receiver transmitted and received ultrasonic waves through the air without contact with the test body. However, it is not limited to non-contact, and scanning may be performed using a liquid contact medium. However, in the case of a test specimen in which the liquid penetrates to the plate wave path, it is preferable to perform the test without contact because it causes noise. In the case of non-contact, scanning can be performed at high speed, and pre-processing and post-processing are not required as in the case of a contact medium. Therefore, it is desirable to perform non-contact scanning also from these points.

  Moreover, in the said embodiment, the ultrasonic wave used the ultrasonic wave of the low frequency band so that the influence of attenuation | damping with a heat insulating material may become small. However, any material that is not affected by attenuation can be applied not only to ultrasonic waves in a low frequency band.

  Moreover, in the said embodiment, the burst wave was used for the ultrasonic wave so that an ultrasonic wave might enter reliably into a test body and a plate wave might be efficiently generated in the 2nd member. However, the type of ultrasonic wave is not particularly limited as long as the second member can generate a plate wave, and for example, a chirp wave may be used. By using a chirp wave, the S / N ratio can be improved.

  The configuration, material, and numerical values of the inspection apparatus and test body of the present invention are not limited to the above-described embodiments, and various modifications can be made as long as they match the gist of the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be used as an ultrasonic inspection method for a multilayer structure used for an outer wall or exterior of a rocket, an artificial satellite, an aircraft, an automobile, etc. and an ultrasonic inspection apparatus used therefor. Furthermore, it can be applied as a peeling inspection of a thin coating film such as coating on a thin plate. For example, it can be used as an inspection method and an inspection apparatus for metal coating peeling, resin coating peeling, metal plating failure, and the like.

1 is a block diagram of an ultrasonic inspection apparatus according to the present invention. It is the schematic of a scanning unit. It is a center sectional view of a sensor unit. It is the schematic which shows the positional relationship of a defect position and a transmitter / receiver, (a) is a healthy part, (b) is a case where a defect is located directly under a transmitter, (c) is a case where a defect is located directly under a receiver. (D) is a figure which shows the case where a defect is located between transmitter / receiver. (A)-(d) is a graph which shows the received waveform in the positional relationship shown to Fig.4 (a)-(d). It is a graph which shows the relationship between the product of the frequency of the ultrasonic wave about each plate wave mode (code | symbol A0-5, S0-5), and the thickness of a test body, and an incident angle in the inspection apparatus of this invention. It is a figure which shows the relationship between the scanning direction by a sensor unit, and the artificial peeling position provided in the test body. 8 is a C-scan image obtained by performing scanning on the test body shown in FIG. 7. It is the schematic which shows other embodiment of the ultrasonic inspection apparatus which concerns on this invention. It is the schematic which shows other embodiment of the ultrasonic inspection apparatus which concerns on this invention. It is explanatory drawing of the conventional ultrasonic testing method, (a) is explanatory drawing which shows the case where a high frequency is used, (b) is the case where a low frequency is used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Ultrasonic inspection apparatus, 10: Sensor unit, 11: Storage room, 15: Top plate, 16: Side wall, 17, 17a, b: Transceiver support pillar, 18: 1st adjustment screw, 19: Contact part, 19a: slope, 20: scanning unit, 24: specimen storage box, 24a: mounting table, 25: scanning mechanism, 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, 31: Transmitter body, 32: Vibrator, 33: Cable, 40: Receiver, 41: Receiver body, 42: vibrator, 43: cable, 50: tilt adjustment mechanism, 51: support plate, 52: second adjustment screw, 53a: first support arm, 53b: second support arm, 60: drive unit, 61: function Generator: 62: Preamplifier, 64: A / D converter, 65: Motor driver, 70: Operation / signal processing unit, 72: Motor controller, 73: Control device, 76: Processing device, 77: Display, 80: Sensor unit , 81: support frame, 82: shaft, 83: pressing body (spring), 84: swing mechanism, 85: housing, 86: support leg, 86a: leg portion, 86b: wheel, 100: specimen (multi-layer structure) Body), 100a: specimen surface, 101, 101 ′: heat insulating material (first member), 102, 102 ′: thin plate (second member), 103: honeycomb structure, 200: probe (sensor), D , D ′: Defect, D1-6: Artificial peeling, E: Distance between incident and receiving points, F: Transmitter / receiver mounting central axis, G: Normal, H: Distance between transmitter and receiver surface, L1: First swing direction axis L2: propagating section surface, L3: second oscillating axis, M1 to M3: drive motor, P: focus, X: the scanning direction, Y: stepping direction, theta: the tilt angle

Claims (4)

An ultrasonic inspection method in which ultrasonic waves are incident on a test body from a transmitter to generate a plate wave in the test body, and ultrasonic waves leaking from the test body are received by the receiver to inspect the test body. There,
The test body is a multilayer structure of two or more layers including at least a first member that is located on an ultrasonic wave incident side and that can transmit ultrasonic waves, and a second member that can propagate plate waves. The member is made of a high-attenuation material of ultrasonic waves, and the ultrasonic waves are ultrasonic waves in a low frequency band so as to reduce attenuation in the test body, and the ultrasonic waves are incident from the first member and the second member The transmitter or receiver in the direction of ultrasonic transmission / reception of the transmitter or receiver is received according to the amplitude of the received signal by receiving a leaky wave generated from the plate wave propagating through the second member. And an ultrasonic inspection method for detecting a defect existing between the second member. The ultrasonic inspection method according to claim 1, wherein the transmitter and the receiver transmit and receive the ultrasonic waves to and from the test body via gas. The ultrasonic inspection method according to claim 1, wherein the transmitter and the receiver are scanned along the surface of the specimen. An ultrasonic inspection apparatus used in the ultrasonic inspection method according to claim 1,
The test body is a multilayer structure of two or more layers including at least a first member that is located on an ultrasonic wave incident side and that can transmit ultrasonic waves, and a second member that can propagate plate waves. The member is made of a high-attenuation material of ultrasonic waves, and the ultrasonic waves are ultrasonic waves in a low frequency band so as to reduce attenuation in the test body, and the ultrasonic waves are incident from the first member and the second member Generating a plate wave, receiving a leaky wave generated from the plate wave propagating through the second member, and depending on the amplitude of the received signal, the transmitter or the receiver inside the first member in the transmission / reception direction of ultrasonic waves or An ultrasonic inspection apparatus for detecting a defect at an interface between the first member and the second member.