Ultrasonic examination apparatus and method

Abstract

The present application relates to an ultrasonic inspection apparatus and an ultrasonic inspection method. The ultrasonic inspection apparatus includes an acquisition unit that acquires, for each scan position, a signal representing a fundamental wave and a second harmonic of an ultrasonic wave obtained by scanning an ultrasonic wave against an inspection object via a medium; a calculation unit that calculates, for each scan position, a value obtained by dividing a second harmonic amplitude by a square of a fundamental wave amplitude; and an output unit that outputs information on a defect of the inspection object based on the value obtained by dividing the square of the fundamental wave amplitude.

Description

Technical Field

[0001] This invention relates to an ultrasonic inspection apparatus and an ultrasonic inspection method. Background Technology

[0002] Patent Document 1 discloses an apparatus for detecting defects in metal parts using a nonlinear ultrasonic immersion method. The apparatus sends ultrasonic waves (sine pulse waves) to a metal part placed in water and receives the transmitted ultrasonic waves. The apparatus detects defects in the metal part based on the value of A2 / A1, obtained by dividing the second harmonic amplitude A2 of the transmitted ultrasonic waves by the fundamental amplitude (incident wave amplitude) A1.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2005-106636

[0004] In the immersion nonlinear ultrasonic method, ultrasonic waves propagating in water as a medium are used to detect defects in metal parts. Therefore, the nonlinearity of water affects the fundamental amplitude A1 and the second harmonic amplitude A2 of the ultrasonic waves. The effect of the nonlinearity of water is not necessarily the same for both the fundamental amplitude A1 and the second harmonic amplitude A2. Therefore, the device described in Patent Document 1 has the following concern: the defects detected based on the value of A2 / A1 may include false detections caused by the nonlinearity of water. Summary of the Invention

[0005] This invention provides an ultrasonic inspection device that can improve the inspection accuracy of defects in the object being inspected.

[0006] The ultrasonic inspection apparatus according to the present invention includes: an acquisition unit that acquires signals representing the fundamental wave and second harmonic wave of an ultrasonic wave obtained by scanning an ultrasonic wave over an object under inspection via a medium at each scanning position; a calculation unit that calculates a value obtained by dividing the amplitude of the second harmonic wave by the square of the amplitude of the fundamental wave at each scanning position; and an output unit that outputs information about defects in the object under inspection based on the value obtained by dividing by the square of the amplitude of the fundamental wave.

[0007] In this ultrasonic inspection apparatus, the acquisition unit acquires signals representing the fundamental and second harmonic waves of the ultrasonic wave being scanned for each scanning position. Furthermore, for each scanning position, the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude is calculated. The fundamental amplitude of the ultrasonic wave is described as a linear function reflecting the nonlinearity of the medium. The second harmonic amplitude of the ultrasonic wave is described as a quadratic function reflecting the nonlinearity of the medium. That is, the influence of the nonlinearity of the medium on the amplitude is the same for both the second harmonic amplitude and the value obtained by squaring the fundamental amplitude. This ultrasonic inspection apparatus can describe the relationship between the second harmonic amplitude and the fundamental amplitude by using the ratio of the second harmonic amplitude to the square of the fundamental amplitude, while reducing the influence caused by the nonlinearity of the medium. Therefore, compared with the case where defects in the object are detected based on the ratio of the second harmonic amplitude of the ultrasonic wave to the fundamental amplitude of the ultrasonic wave (A2 / A1), this ultrasonic inspection device can improve the detection accuracy of defects in the object.

[0008] In one embodiment, the output unit outputs an image as information about the defects in the object being inspected. In this case, the ultrasonic inspection device can visualize the location of the defects in the object being inspected.

[0009] In one embodiment, the calculation unit calculates the value obtained by dividing the second harmonic amplitude by the fundamental amplitude for each scanning position, and the output unit outputs information about the defects of the inspected object based on the value obtained by dividing the second harmonic amplitude by the fundamental amplitude and the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude. The fundamental amplitude and the second harmonic amplitude vary depending on the reflectivity of the ultrasonic wave at the interface between the medium and the inspected object, and the reflectivity of the ultrasonic wave at the defect of the inspected object. Furthermore, the reflectivity has the same effect on the amplitude for both the fundamental amplitude and the second harmonic amplitude. This ultrasonic inspection device can use the ratio of the fundamental amplitude to the second harmonic amplitude of the ultrasonic wave to describe the relationship between the fundamental amplitude and the second harmonic amplitude of the ultrasonic wave while reducing the influence caused by reflectivity. Therefore, this ultrasonic inspection device can use the ratio of the second harmonic amplitude to the fundamental amplitude of the ultrasonic wave to reduce the influence of the reflectivity of the ultrasonic wave on the amplitude.

[0010] Other aspects of the present invention relate to an ultrasonic inspection method comprising: for each scanning position, obtaining signals representing the fundamental wave and second harmonic of an ultrasonic wave obtained by scanning an ultrasonic wave across a medium onto an object under inspection; for each scanning position, calculating a value obtained by dividing the second harmonic amplitude by the square of the fundamental wave amplitude; and outputting information about defects in the object under inspection based on the value obtained by dividing by the square of the fundamental wave amplitude.

[0011] In this ultrasonic inspection method, for each scanning position, signals representing the fundamental and second harmonic waves of the ultrasonic wave being scanned and inspected are acquired. Furthermore, the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude is calculated. That is, this ultrasonic inspection method can use the ratio of the second harmonic amplitude to the square of the fundamental amplitude to describe the relationship between the second harmonic amplitude and the fundamental amplitude, thereby reducing the influence of nonlinearity of the medium. Therefore, this ultrasonic inspection method can improve the detection accuracy of defects in the inspected object.

[0012] Furthermore, another aspect of the ultrasonic inspection apparatus according to the present invention includes: an acquisition unit that acquires signals representing the fundamental and second harmonic waves of ultrasound obtained by scanning an ultrasonic wave across a medium onto an object to be inspected at each scanning position; and an output unit that outputs an image related to the object to be inspected, the image having pixel values ​​corresponding to each scanning position, the pixel values ​​being values ​​obtained by applying a predetermined pixel value conversion rule to the value obtained by dividing the second harmonic amplitude at the corresponding scanning position by the square of the fundamental amplitude. In this ultrasonic inspection apparatus, the acquisition unit acquires signals representing the fundamental and second harmonic waves of ultrasound obtained by scanning an ultrasonic wave onto an object to be inspected at each scanning position. Moreover, the output unit outputs an image related to the object to be inspected. The image has pixel values ​​corresponding to each scanning position, the pixel values ​​being values ​​obtained by applying a predetermined pixel value conversion rule to the value obtained by dividing the second harmonic amplitude at the corresponding scanning position by the square of the fundamental amplitude. Therefore, this ultrasonic inspection apparatus uses the ratio of the second harmonic amplitude of the ultrasound to the square of the fundamental amplitude of the ultrasound to visualize the relationship between the second harmonic amplitude and the fundamental amplitude under a state where the influence caused by the nonlinearity of the medium is reduced.

[0013] The ultrasonic inspection apparatus according to the present invention can improve the detection accuracy of defects in the inspected object. Attached Figure Description

[0014] Figure 1 This is a schematic diagram illustrating an example of an ultrasonic inspection device system.

[0015] Figure 2 It means Figure 1 A block diagram illustrating the functions of an ultrasonic testing device.

[0016] Figure 3 This is a schematic diagram illustrating the propagation path of the ultrasound waves on the object 7 being scanned.

[0017] Figure 4 This is an example of checking information about defects in an object.

[0018] Figure 5This is a flowchart illustrating the process of an ultrasound examination.

[0019] Figure 6 This is a schematic diagram illustrating the multiple propagation paths of ultrasound waves on the object 7 being scanned.

[0020] Explanation of reference numerals in the attached figures

[0021] 100…Ultrasonic inspection system; 1…Control device; 2…Pulse generator; 3…Bell splitter; 4…Drive unit; 5…Ultrasonic probe; 6…Water tank; 7…Inspection object; 8…High frequency filter; 9…Pulse receiver; 10…Ultrasonic inspection device; 11…Acquisition unit; 12…Calculation unit; 13…Output unit. Detailed Implementation

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, in the following description, the same reference numerals will be used to denote the same elements or equivalent elements, and descriptions will not be repeated. The scale of the accompanying drawings may not be the same as the scale of the description. The terms "upper," "lower," "left," and "right" are used based on the illustrated states for ease of explanation.

[0023] [Structure of an Ultrasonic Examination System]

[0024] Figure 1 This is a schematic diagram illustrating an example of an ultrasonic inspection apparatus system. The X and Y directions in the diagram are horizontal, and the Z direction is vertical. The X, Y, and Z directions are mutually orthogonal axes in a three-dimensional orthogonal coordinate system. The ultrasonic inspection system 100 includes: a control device 1, a pulse generator 2, a wave splitter 3, a drive unit 4, an ultrasonic probe 5, a water tank 6, an object to be inspected 7, a high-frequency filter 8, a pulse receiver 9, and an ultrasonic inspection device 10. The ultrasonic inspection system 100 uses ultrasonic waves to scan the object to be inspected 7 and outputs information about the defects in the object to be inspected 7.

[0025] The control device 1 is, for example, a general-purpose computer equipped with an arithmetic unit such as a CPU (central processing unit), a storage device such as ROM (read-only memory), RAM (random access memory), and HDD (hard disk drive), as well as a communication device. The control device 1 is connected to the pulse generator 2, the drive unit 4, and the ultrasonic inspection device 10.

[0026] Pulse generator 2 generates a voltage that causes ultrasonic probe 5 to generate ultrasonic waves. Pulse generator 2 modifies the waveform of the voltage according to instructions from control device 1. Pulse generator 2 is connected to ultrasonic probe 5 and high-frequency filter 8 via wave splitter 3. Pulse generator 2 causes ultrasonic probe 5 to generate ultrasonic waves corresponding to the voltage. As an example, pulse generator 2 causes ultrasonic probe 5 to generate sinusoidal pulse waves. Sinusoidal pulse waves are instantaneously generated sinusoidal ultrasonic waves. The amplitude or frequency of the sinusoidal pulse wave is determined by the waveform of the voltage generated by pulse generator 2.

[0027] The drive unit 4 is positioned above the water tank 6 and includes multiple movable axes for moving the ultrasonic probe 5. These movable axes are, for example, composed of ball screw mechanisms along the X, Y, and Z axes. The ball screw mechanisms are driven by servo motors. The drive unit 4 moves the ultrasonic probe 5 according to instructions from the control device 1. The drive unit 4 feeds back the position information of the ultrasonic probe 5 to the control device 1.

[0028] The ultrasonic probe 5 receives voltage from the pulse generator 2 to generate ultrasonic waves. The ultrasonic probe 5 has a probe surface with an internal piezoelectric element. The ultrasonic probe 5, having received voltage, generates ultrasonic waves corresponding to the voltage from the probe surface. For the ultrasonic probe 5, if the probe surface receives ultrasonic waves, an electrical signal representing the received ultrasonic waves is generated. The electrical signal is an analog signal based on changes in voltage value.

[0029] A water tank 6 contains water 6a. The object to be inspected 7 is supported in the water 6a by a sample placement stage 6b inside the water tank 6. The water 6a functions as a medium for propagating ultrasonic waves generated by the ultrasonic probe 5 towards the object to be inspected 7. As an example, the object to be inspected 7 is a composite material consisting of an aluminum layer 71 and a CFRP (carbon fiber reinforced plastic) layer 72. The object to be inspected 7 reflects the propagating ultrasonic waves. The sample placement stage 6b supports the object to be inspected 7 in a manner that prevents the ultrasonic waves propagating to the object to be inspected 7 from propagating back into the water tank 6.

[0030] An ultrasonic probe 5 irradiates an object 7 with ultrasonic waves. Additionally, the ultrasonic probe 5 receives the ultrasonic waves reflected from the object 7. If the ultrasonic wave irradiated by the ultrasonic probe 5 is denoted as U, the ultrasonic wave reflected from the object 7 contains a fundamental wave with the same frequency as ultrasonic wave U, and an nth harmonic with a frequency n times the frequency of ultrasonic wave U (n is a natural number). The process of irradiating the object 7 with ultrasonic wave U by the ultrasonic probe 5 and receiving the ultrasonic waves reflected from the object 7 is called scanning. The ultrasonic waves obtained by scanning the object 7 contain at least the fundamental wave and the second harmonic.

[0031] The ultrasonic probe 5 scans and inspects the object 7 using ultrasound at a predetermined position. Then, the drive unit 4 moves the ultrasonic probe 5. The ultrasonic probe 5 scans and inspects the object 7 again using ultrasound at the moved position. The drive unit 4 moves the ultrasonic probe 5 along a predetermined path. The path controlled by the control device 1 is preset in the XY plane to comprehensively scan and inspect the object 7 using ultrasound.

[0032] The ultrasonic probe 5 is connected to the ultrasonic inspection device 10 via a high-frequency filter 8 and a pulse receiver 9. The ultrasonic probe 5 transmits the ultrasonic waves obtained by scanning the object 7 as electrical signals to the ultrasonic inspection device 10.

[0033] The high-frequency filter 8 includes, for example, an electronic circuit with a variable resistor and a variable capacitor. The high-frequency filter 8 reduces low-frequency components lower than a specified frequency from the electrical signal transmitted by the ultrasonic probe 5. The electrical signal transmitted by the ultrasonic probe 5 contains components representing the ultrasonic waves obtained by scanning the object 7, as well as components generated by external interference such as power supply voltage fluctuations and radio waves. The electrical signal representing the ultrasonic waves obtained by scanning the object 7 contains more high-frequency components, and therefore passes through the high-frequency filter 8. On the other hand, external interference such as power supply voltage fluctuations and radio waves contains more low-frequency components, and therefore is reduced by the high-frequency filter 8.

[0034] The pulse receiver 9 receives the ultrasonic electrical signal obtained from the scanning inspection object 7 via the high-frequency filter 8. The pulse receiver 9, for example, includes electronic circuitry with an operational amplifier and an A / D (analog-to-digital converter). The pulse receiver 9 converts the voltage changes of the received electrical signal into a digital signal. The digital signal is a rectangular wave representing the voltage value. The pulse receiver 9 transmits the digital signals representing the fundamental frequency and the second harmonic to the ultrasonic inspection device 10.

[0035] The ultrasonic inspection device 10 outputs information about defects in the object 7 based on ultrasonic waves obtained by scanning the object 7.

[0036] [Structure of Ultrasonic Inspection Device]

[0037] Figure 2 It means Figure 1 A block diagram illustrating the functions of an ultrasonic inspection device. The ultrasonic inspection device 10 includes an acquisition unit 11, a calculation unit 12, and an output unit 13. The ultrasonic inspection device 10 may be configured, for example, as a general-purpose computer having an arithmetic unit such as a CPU (central processing unit), a storage device such as ROM (read-only memory), RAM (random access memory), and HDD (hard disk drive), as well as a communication device.

[0038] The acquisition unit 11 acquires the fundamental wave and second harmonic of the ultrasonic wave obtained by the ultrasonic probe 5 scanning the inspection object 7 based on the digital signal transmitted by the pulse receiver 9. Additionally, the acquisition unit 11 acquires the position information of the ultrasonic probe 5 fed back by the drive unit 4 from the control device 1. The acquisition unit 11 compares the acquired fundamental wave and second harmonic of the ultrasonic wave with the position information fed back by the drive unit 4, establishing a relationship between the fundamental wave and second harmonic of the ultrasonic wave obtained by the ultrasonic probe 5 scanning the inspection object 7 and the position information when the ultrasonic probe 5 scans the inspection object 7. That is, the acquisition unit 11 acquires signals representing the fundamental wave and second harmonic for each scanning position along the path of the ultrasonic probe 5.

[0039] The calculation unit 12 calculates the value obtained by dividing the second harmonic amplitude by the fundamental amplitude based on the signals representing the fundamental frequency and the second harmonic acquired by the acquisition unit 11. The principle for outputting information about defects in the inspection object 7 will be explained below.

[0040] Figure 3 This is a schematic diagram illustrating the propagation path of the ultrasound waves on the object being scanned (7). It is constructed using the ultrasound probe 5 (refer to...). Figure 1 The transmitted ultrasonic wave passes through the water 6a to the aluminum layer 71. The ultrasonic wave that passes through the water 6a to the aluminum layer 71 is reflected at the bonding interface 7a. The ultrasonic wave that is reflected at the bonding interface 7a passes through the aluminum layer 71 back to the water 6a. The ultrasonic wave that propagates in the water 6a is received by the ultrasonic probe 5. Here, the material density ρ, the longitudinal elastic modulus E, and the Poisson's ratio ν are generally used, and the ultrasonic longitudinal wave velocity C of a linear continuum that follows Hooke's law is expressed by the following mathematical expression (1).

[0041]

[0042] However, the stress-deformation relationship defined by atomic force exhibits nonlinearity. If the second-order term of the deformation ε is taken into account, then the quadratic elastic constant C, which is affected by the nonlinear propagation path of water, is used. 1W The cubic elastic constant C of the propagation path affected by the nonlinearity of water. 2W The stress σ is represented by the following mathematical expression (2).

[0043] σ=C 1W ε+C 2W ε 2 (2)

[0044] The displacement u of the one-dimensional wave equation of the elastic body that follows mathematical expression (2) is given by the following mathematical expression (3).

[0045]

[0046] K represents the wave number, x represents the propagation distance, ω represents the angular frequency, t represents time, and i represents the imaginary unit. A 1W This represents the fundamental frequency amplitude of the ultrasonic wave U transmitted by the ultrasonic probe 5, which is affected by the nonlinearity of water 6a.

[0047] Based on mathematical expression (3), the following mathematical expressions (4) and (5) represent the process through... Figure 3 The fundamental amplitude A1 and second harmonic amplitude A2 of the ultrasound obtained by scanning the propagation path of object 7 are shown.

[0048] A1=RT1T2A 1W (4)

[0049]

[0050] R represents the reflectivity of the adhesive interface 7a, T1 represents the transmittance from water 6a to aluminum layer 71, T2 represents the transmittance from aluminum layer 71 to water 6a, and α represents the signal generated by the tapping.

[0051] Based on mathematical expressions (4) and (5), the following mathematical expression (6) represents the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude.

[0052]

[0053] The mathematical expression (6) representing the ratio of the second harmonic amplitude of the ultrasound obtained by scanning the object 7 to the value obtained by squaring the fundamental amplitude of the ultrasound is used to eliminate A, which is affected by the nonlinearity of water 6a, from the first term on the right. 1W This. Furthermore, the second term on the right, including the signal α generated by the impact, is sufficiently small. Therefore, the calculation unit 12 calculates the value obtained by reducing the nonlinear effect of the water 6a. The calculation unit 12 calculates the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude for each scanning position along the path of the ultrasonic probe 5.

[0054] The output unit 13 outputs information about defects in the inspection object 7 for each scanning position along the path of the ultrasonic probe 5, based on the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude, calculated by the calculation unit 12. Defects in the inspection object 7 are locations within the inspection object 7 where the elastic constant changes discontinuously, such as minute cracks at the bonding interface 7a between the aluminum layer 71 and the CFRP layer 72. The first term on the right-hand side of the mathematical expression (6) is the cubic elastic constant C, which is affected by the nonlinearity of water. 2W The second elastic constant C, which is affected by the nonlinearity of water. 1WThe ratio changes accordingly with the state of the defect in the inspection object 7, thus containing information about the defect. The state of the defect is, for example, the width and area of ​​a small crack that has occurred at the bonding interface 7a. Thus, the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude, expressed using mathematical expression (6), contains information about the defect in the inspection object 7 that reduces the nonlinear effect of water 6a. The output unit 13 applies a prescribed pixel conversion rule to the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude, expressed using mathematical expression (6), and generates an image based on the converted pixel value. For example, the output unit 13 may also multiply the value obtained for each scanning position by a prescribed conversion coefficient to convert it into a pixel value, and generate an image based on the converted pixel value. That is, the image has pixel values ​​corresponding to the scanning positions respectively. As a specific example of the prescribed pixel value conversion rule, the grayscale image generation step will be explained. First, the output unit 13 establishes a correspondence between the scanning position and the pixel position contained in the image. Next, the output unit 13 establishes a correspondence between the grayscale of the image and the defect information. The output unit 13 establishes a correspondence between defect information and grayscale values ​​in such a way that the amplitude (range) of the defect information obtained at each scanning position converges within the grayscale range of the grayscale image, and the defect information is proportional to the grayscale value. For example, the output unit 13 establishes a correspondence between the minimum value of the defect information and the weakest grayscale value (black), and between the maximum value of the defect information and the strongest grayscale value (white). When grayscale is represented by 8 bits, pixel value 0 is the minimum value of the defect information, corresponding to A2 / A1 of the normal area. 2 Corresponding. Pixel value 255 is the maximum value of the defect information, corresponding to A2 / A1 of the defective area. 2 Correspondingly, according to this conversion rule, the image output represents the area where the color is closer to white and the more likely there is a defect. The output unit 13 can also convert the image signal corresponding to the scan position into a more detailed image signal corresponding to the scan position by electrically segmenting the image signal. In this case, the accuracy of the boundary value between normal areas (black) and defective areas (white) can be improved. Furthermore, the output unit 13 can also output the A2 / A1 values ​​of normal areas. 2 A threshold is set based on a baseline, automatically identifying defective areas. For example, a pre-set A2 / A1 value is used for normal areas. 2 As a threshold, it will be compared with A2 / A1 which is greater than the threshold. 2 The corresponding pixel value is used to identify the defective part.

[0055] Figure 4 This is an example of checking information about defects in an object. Figure 4(A) is a value obtained by calculating the second harmonic amplitude by dividing the square of the fundamental amplitude based on experiments, and the information of the defects of the inspection object 7 is output based on the calculated value. The information of the defects of the inspection object 7 is output as an image by the output unit 13 to a two-dimensional plane corresponding to the scanning position of the path of the ultrasonic probe 5. Figure 4 (B) is the value obtained by dividing the second harmonic amplitude by the fundamental amplitude based on experiments, and the information on the defects of the inspection object 7 is output based on the calculated value. Figure 4 (A) and Figure 4 Compared to (B), it was confirmed that the information regarding the defects of the expanded circular inspection object 7 was correctly visualized. By applying the reverse steps of the pixel value conversion rules described above to the pixel values ​​contained in the image, all pixel values ​​were converted to A2 / A1 at the corresponding scan position. 2 In this case, the image may also be referred to as an image generated using the method of the present invention.

[0056] [Operation of the ultrasonic testing device]

[0057] Figure 5 This is a flowchart illustrating the process of an ultrasound examination. Figure 5 The flowchart shown is executed by the ultrasonic inspection device 10.

[0058] like Figure 5 As shown, initially, the ultrasonic inspection apparatus 10 performs a process (step S11) to acquire the position of the ultrasonic probe 5 scanning the inspection object 7, and to acquire the fundamental wave and second harmonic of the ultrasonic wave obtained by scanning the inspection object 7. The acquisition process (step S11) is based on the digital signal output from the pulse receiver 9 and the feedback from the drive unit 4.

[0059] Next, a calculation process (step S12) is performed, whereby the ultrasonic inspection device 10 scans each position of the inspection object 7 with the ultrasonic probe 5, and calculates the value obtained by dividing the amplitude of the second harmonic by the square of the amplitude of the fundamental wave, based on the obtained fundamental wave and second harmonic. In the calculation process (step S12), information on the defects of the inspection object 7 that reduces the nonlinear effect of water 6a is calculated as described above, based on the mathematical expression (6).

[0060] Next, output processing (step S13) is performed, that is, the ultrasonic inspection device 10 outputs information about the defects of the inspection object 7 based on the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude. Information about the defects of the inspection object 7, such as the width and area of ​​minute cracks contained in the adhesive interface 7a, is output according to the change in the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude. The information about the defects of the inspection object 7 is output, for example, as an image. If the output processing (step S13) ends, then... Figure 5The flowchart shown ends here.

[0061] [Summary of Implementation Methods]

[0062] According to the ultrasonic inspection apparatus 10 and the ultrasonic inspection method, the fundamental and second harmonic signals of the ultrasonic waves obtained by the ultrasonic probe 5 scanning the inspection object 7 are acquired at each scanning position along the path of the ultrasonic probe 5 in the acquisition unit 11. The value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude is calculated at each scanning position along the path of the ultrasonic probe 5 in the calculation unit 12. Information on defects in the adhesive interface 7a of the inspection object 7, based on the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude and reducing the nonlinear effect of water 6a, is output from the output unit 13. Thus, the ultrasonic inspection apparatus 10 can output defects in the inspection object 7 that reduce the nonlinear effect of water 6a. Therefore, compared to detecting defects in the inspection object 7 based on the ratio (A2 / A1) of the second harmonic amplitude to the fundamental amplitude of the ultrasonic wave, this ultrasonic inspection apparatus 10 and ultrasonic inspection method can improve the detection accuracy of defects in the inspection object 7.

[0063] The output unit 13 can output images as information about defects in the object 7 under inspection. The ultrasonic inspection device 10 can visualize the defects in the object 7 under inspection.

[0064] [Variation Example]

[0065] The above describes various illustrative implementation methods, but it is not limited to the illustrative implementation methods described above, and various omissions, substitutions, and changes can be made.

[0066] The output unit 13 may not output information about the defects of the inspection object 7 as an image. For example, the output unit 13 may output the change in the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude in graphical form. The output unit 13 may also output the inspection result based on the information about the defects of the inspection object 7. The inspection result may, for example, be a judgment result indicating whether the inspection object 7 is qualified or unqualified.

[0067] The calculation unit 12 calculates the value obtained by dividing the second harmonic amplitude of the ultrasound wave obtained by scanning by the fundamental amplitude for each scanning position along the path of the ultrasonic probe 5. The output unit 13 can also output information about the defects of the inspection object 7 based on the value obtained by dividing the second harmonic amplitude by the fundamental amplitude and the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude. The principle of outputting information about the defects of the inspection object 7 will be explained below.

[0068] Figure 6This is a schematic diagram illustrating multiple propagation paths of ultrasonic waves on the object being inspected (7). The propagation paths of the ultrasonic waves obtained during the scanning inspection of the object 7 include reflections at the external interface 7b between the aluminum layer 71 and the water 6a, reflections at the intact portions of the adhesive interface 7a of the object being inspected, and reflections at the defective portions of the adhesive interface 7a of the object being inspected. The reflectivity of the external interface 7b between the aluminum layer 71 and the water 6a is set as R. W The reflectivity of the intact portion of the adhesive interface 7a of the inspection object 7 is set to R. G Since there is no nonlinearity at any interface, A2 / A1 can be represented by mathematical expressions (7) and (8) as the case where the signal α = 0 generated by the tapping. 2 and A2′ / A1′ 2 .

[0069]

[0070]

[0071] A1′ represents the fundamental amplitude of the ultrasonic wave reflected from the healthy portion of the adhesive interface 7a of the inspected object 7. A2′ represents the second harmonic amplitude of the ultrasonic wave reflected from the healthy portion of the adhesive interface 7a of the inspected object 7. The ratio of mathematical expression (7) to mathematical expression (8) is expressed by the following mathematical expression (9).

[0072]

[0073] According to mathematical expression (4), the following mathematical expression (10) represents the ratio of the amplitude of the fundamental wave reflected at the external interface 7b between the aluminum layer 71 and the water 6a to the amplitude of the fundamental wave reflected from the intact part of the adhesive interface 7a of the inspection object 7.

[0074]

[0075] Here, if we use mathematical expression (10) to transform mathematical expression (9), we obtain the following mathematical expression (11).

[0076]

[0077] If we rearrange both sides of the mathematical expression (11), we obtain the following mathematical expression (12).

[0078]

[0079] The reflectivity of the defective portion of the adhesive interface 7a of the inspection object 7 is set to R. FThe fundamental amplitude of the ultrasonic wave reflected from the defective part of the adhesive interface 7a of the inspected object 7 is set as A1″, and the second harmonic amplitude of the ultrasonic wave reflected from the defective part of the adhesive interface 7a of the inspected object 7 is set as A2″. If A2″ / A1″ is calculated in the same way as the above mathematical expression, the following mathematical expression (13) is obtained.

[0080]

[0081] If we rearrange both sides of the mathematical expression (13) and combine the terms containing α into A(α), we obtain the following mathematical expression (14).

[0082]

[0083] The ratio of the second harmonic amplitude to the fundamental amplitude of the ultrasonic wave obtained by scanning ultrasonic waves, as expressed in mathematical expressions (12) and (14), is a constant value except for the term A(α), even if the ultrasonic wave is reflected at any of the external interface 7b, the internal adhesive interface 7a, or the defect of the object under inspection 7. That is, for the fundamental amplitude and the second harmonic amplitude of the ultrasonic wave reflected at different propagation paths, the relationship between the fundamental amplitude and the second harmonic amplitude of the ultrasonic wave can be described by using the ratio of the second harmonic amplitude to the fundamental amplitude of the ultrasonic wave, under the condition of reducing the influence caused by reflectivity.

[0084] The calculation unit 12 calculates for each scanning position along the path of the ultrasonic probe 5 the value obtained by dividing the second harmonic amplitude of the ultrasonic wave by the fundamental amplitude of the ultrasonic wave and the value obtained by dividing the second harmonic amplitude of the ultrasonic wave by the square of the fundamental amplitude of the ultrasonic wave.

[0085] The output unit 13 outputs information about the defects in the inspection object 7 based on the values ​​obtained by dividing the second harmonic amplitude of the ultrasonic wave by the fundamental amplitude of the ultrasonic wave, calculated by the calculation unit 12, and the values ​​obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude. Specifically, the output unit 13 compares the image output based on the value obtained by dividing the second harmonic amplitude by the fundamental amplitude with the image output based on the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude. If the proportion of the images with consistent defect locations is lower than any value when comparing the images, the output unit 13 outputs an indication that the defect was falsely detected due to the influence of the ultrasonic wave's reflectivity on the amplitude. Thus, the ultrasonic inspection device 10 can reduce the influence of the ultrasonic wave's reflectivity on the amplitude by using the ratio of the second harmonic amplitude of the ultrasonic wave to the fundamental amplitude of the ultrasonic wave, and the ratio of the second harmonic amplitude of the ultrasonic wave to the value obtained by squared the fundamental amplitude of the ultrasonic wave.

[0086] The acquisition unit 11 can also acquire and scan the ultrasonic waves passing through and scanning the inspection object 7. The principle for outputting information about defects in the inspection object 7 will be explained below.

[0087] The ultrasonic waves scanning the object 7 pass through the external interface 7b between the aluminum layer 71 and the water 6a, the adhesive interface 7a of the object 7, and between the CFRP and the water 6a. In this case, the fundamental amplitude and the second harmonic amplitude passing through the object 7 are represented by the following mathematical expressions (15) and (16).

[0088] A1=T5T1T3A 1W (15)

[0089]

[0090] T3 represents the transmittance from aluminum layer 71 to CFRP layer 72. T5 represents the transmittance from CFRP layer 72 to water 6a. In the case of obtaining and scanning the ultrasonic waves transmitted through the object 7, the value obtained by dividing the second harmonic amplitude by the square of the fundamental amplitude is expressed by the following mathematical expression (17) according to mathematical expressions (15) and (16).

[0091]

[0092] In mathematical expression (17), the ratio of the second harmonic amplitude of the ultrasonic wave to the square of the fundamental amplitude of the ultrasonic wave is expressed. Similarly, in mathematical expression (6), the A value affected by the nonlinearity of water 6a is eliminated from the first term on the right. 1W Therefore, the ultrasonic inspection device 10 can output defects in the inspection object 7 that have been reduced by the nonlinear effects of water 6a, just as the ultrasonic waves that are reflected and scanned by the acquisition unit 11 are obtained through and scanned by the acquisition unit 11.

Claims

1. An ultrasonic testing apparatus characterized by comprising: Possessing: an acquisition unit that acquires, for each scan position, a signal representing a fundamental wave and a second harmonic of the above-described ultrasonic wave obtained by scanning an ultrasonic wave against a composite material composed of an aluminum layer and a CFRP layer via water; a calculation unit that calculates, for each scan position, a value obtained by dividing the second harmonic amplitude by the square of the fundamental wave amplitude; and an output unit that outputs information on a defect of the above-described composite material based on the value obtained by dividing the fundamental wave amplitude by the square, the defect of the above-described composite material is a crack generated at a bonding interface between the above-described aluminum layer and the above-described CFRP layer.

2. The ultrasonic wave inspection apparatus according to claim 1, characterized in that the above-described output unit outputs an image as the information on the defect of the above-described composite material.

3. The ultrasonic wave inspection apparatus according to claim 1 or 2, characterized in that the above-described calculation unit calculates, for each of the above-described scan positions, a value obtained by dividing the above-described second harmonic amplitude by the above-described fundamental wave amplitude, the above-described output unit outputs the information on the defect of the above-described composite material based on the value obtained by dividing the above-described second harmonic amplitude by the above-described fundamental wave amplitude and the value obtained by dividing the above-described second harmonic amplitude by the square of the above-described fundamental wave amplitude.

4. An ultrasonic inspection method characterized by, Possessing: a step of acquiring, for each scan position, a signal representing a fundamental wave and a second harmonic of the above-described ultrasonic wave obtained by scanning an ultrasonic wave against a composite material composed of an aluminum layer and a CFRP layer via water; a step of calculating, for each of the above-described scan positions, a value obtained by dividing the second harmonic amplitude by the square of the fundamental wave amplitude; and a step of outputting information on a defect of the above-described composite material based on the value obtained by dividing the fundamental wave amplitude by the square, the defect of the above-described composite material is a crack generated at a bonding interface between the above-described aluminum layer and the above-described CFRP layer.

5. An ultrasonic testing apparatus characterized by comprising: Possessing: an acquisition unit that acquires, for each scan position, a signal representing a fundamental wave and a second harmonic of the above-described ultrasonic wave obtained by scanning an ultrasonic wave against a composite material composed of an aluminum layer and a CFRP layer via water; and an output unit that outputs an image related to the above-described composite material, the above-described image has pixel values corresponding to the above-described scan positions respectively, the above-described pixel values are values obtained by applying a prescribed pixel value conversion rule to a value obtained by dividing the second harmonic amplitude at the corresponding above-described scan position by the square of the fundamental wave amplitude, and include information on a crack generated at a bonding interface between the above-described aluminum layer and the above-described CFRP layer.

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