A method and device for detecting vertical defects inside multi-layer solid dielectric materials

Abstract

The present invention aims to solve the common problem that vertical defects inside composite materials with multi-layer solid medium characteristics are difficult to detect. Utilizing the unique multi-layer solid layered structural characteristics in composite materials and the acoustic differences between two solid media to form a boundary effect, a detection method based on the propagation characteristics of ultrasonic creeping waves is proposed: when ultrasonic creeping waves propagate along heterogeneous interfaces, they will excite the characteristics of diffraction waves when encountering defects. Specifically, a composite ultrasonic detection technology combining ultrasonic creeping waves with focusing technology is used, and a device with three-dimensional automatic scanning function is used to develop a simple, fast and practical non-destructive testing technology. The problem that composite materials with layered structural characteristics such as fiber-reinforced metal matrices for integral blade rings of aircraft engines are difficult to detect is solved, and their processing quality and service safety are guaranteed. The method is also applicable to the detection of vertical defects inside other multi-layer solid medium composite materials.

Description

Technical Field

[0001] The present invention relates to the field of non-destructive testing of composite material components, and the test object is a type of composite material with multi-layer solid interface structure characteristics, and there are obvious acoustic differences between each solid layer. For example, SiC fiber reinforced Ti-based composite integral blade ring components for aircraft engines. Background Art

[0002] Composite materials are a new type of material composed of two or more material components with different chemical and physical properties. Among them, there is a type of composite material with a multi-layer solid sandwich structure, which is a structural material used under certain load-bearing conditions, mainly including sandwich composite materials and fiber-reinforced composite materials. Fiber-reinforced metal matrix composite materials have a composite structure of reinforcement and matrix materials, and are widely used in aerospace, nuclear power, weapons and equipment, automobiles and other fields. For example, continuous SiC fiber reinforced titanium matrix composite material (Ti-MMC) is a candidate material for structural parts in the aerospace industry due to its high specific strength, high specific modulus, good dimensional stability and high temperature strength. It is an ideal lightweight and high temperature resistant structural material for aircraft engines. The integral blade ring structure made of SiC fiber reinforced titanium matrix composite material has significant advantages in weight reduction and bearing circumferential loads, and has gradually become an important way to reduce the weight of the engine. However, the current manufacturing cost of silicon carbide fiber is high, and the integral blade ring manufacturing process is not mature enough. Since processing and manufacturing defects have a very large impact on the performance of Ti-MMC, in addition to continuing to break through the key technologies of design and processing and manufacturing of the integral blade ring, it is also necessary to establish non-destructive testing technology for continuous SiC fiber reinforced titanium-based composite rings in order to realize its engineering application.

[0003] Continuous fiber reinforced titanium-based composite materials have a multi-interface composite structure, and the non-destructive detection of defects is much more complicated than that of conventional homogeneous monolithic materials. The defects mainly include: fiber breakage, fiber / matrix separation, fiber sliding and pulling out, matrix cracks, etc., among which fiber breakage is the most harmful. At present, the main detection methods for non-destructive detection of defects in Ti-MMC at home and abroad are: acoustic emission (AE), X-ray and ultrasound. Acoustic emission technology is mainly used in mechanical tests to monitor the dynamic process of fiber breakage during the continuous force application process of the workpiece and study its fracture mechanism. Therefore, it cannot be used for product quality inspection in actual industrial production, and its engineering application is of little significance. X-ray and industrial CT belong to transmission imaging. The emission light intensity, material attenuation coefficient and workpiece size directly determine the accuracy of the detection. When the thickness of the workpiece is greater than 20mm, the image resolution of the two methods is obviously insufficient. Ultrasonic detection technology is a conventional non-destructive detection method, and pulse reflection method is often used in industrial production. For the detection of tiny defects, water-immersion focusing probes are often used to increase the ultrasonic energy in the focal area, and the sensitivity and resolution of tiny defect detection are improved by increasing the probe frequency. For example, an ultrasonic microscope using a 100MHz high-frequency probe can detect cracking defects in fiber rings with a depth of 2 to 3mm. However, as the detection depth increases, the ultrasonic beam diffuses severely, and the imaging resolution of the ultrasonic microscope decreases rapidly. Since the thickness of the integral blade ring parts used in actual engineering applications is mostly between 20mm and 100mm, it is difficult for the above non-destructive testing methods to achieve quality control of the reinforced fiber area. Summary of the invention

[0004] To solve the common problem that vertical defects inside composite materials with multi-layer solid medium characteristics such as integral blade ring (Ti-MMC) components are difficult to detect. The present invention is based on the unique multi-layer solid "sandwich" structural characteristics of this type of material, and uses the acoustic differences between two solid media to form a boundary effect, and proposes a detection method based on the propagation characteristics of ultrasonic creeping waves: when ultrasonic creeping waves propagate along heterogeneous interfaces, they will excite the characteristics of diffraction waves when encountering defects. Specifically, a composite ultrasonic detection technology that combines ultrasonic creeping waves with water immersion focusing technology is used, with the help of a device with a three-dimensional automatic scanning function, to develop a simple and fast inspection technology for the manufacturing quality of fiber-reinforced metal matrix composite structural parts, so as to ensure their processing quality and service safety. The method is also applicable to the detection of vertical defects inside other multi-layer solid medium composite materials.

[0005] The technical solution of the present invention is as follows:

[0006] A method for detecting vertical defects inside a multilayer solid medium composite material is characterized by: utilizing the acoustic difference between two solid media to form a boundary effect, and based on the characteristic that when an ultrasonic creeping wave propagates along a heterogeneous interface and encounters a defect, it will stimulate a diffraction wave for detection. Specifically, a probe group is composed of a creeping wave probe and a receiving probe, the creeping wave probe emits an ultrasonic creeping wave, and the receiving probe receives the diffraction wave and converts it into an electrical signal, thereby implementing detection.

[0007] The multilayer solid medium composite material described in the present invention is a layered composite structure composed of two or more materials with large differences in acoustic properties (preferably the difference in acoustic impedance values ​​is more than 20%), and the defect type to be detected is a vertical defect inside the composite material perpendicular to the detection surface. Since the solid materials of each component are media with different densities and sound velocities, heterogeneous interfaces with different acoustic properties will be formed. When the refracted longitudinal wave propagating in solid medium one is incident on the interface of solid medium two at an appropriate angle, an ultrasonic creeping wave will be stimulated on the interface. When the creeping wave propagates along the interface, it "collides" with the internal vertical defect, generating a diffraction wave, which is then received by a receiving probe to implement detection. The present invention uses a combination of a contact creeping wave probe and an immersion probe, wherein the contact creeping wave probe emits ultrasonic waves and the immersion probe perpendicular to the surface of the workpiece receives the diffraction wave signal, but is not limited to this probe combination, and other forms of probe combinations can also be used.

[0008] When testing composite materials with different material combinations, it is necessary to calculate the sound beam refraction angle β based on the ultrasonic sound velocity in the solid medium of each component, so that the incident wave can excite creeping waves at the interface, and design the creeping wave probe inclination angle according to the refraction angle β. The size range of the probe piezoelectric chip is 10 to 15 mm, and the chip frequency range is 1 MHz to 15 MHz.

[0009] The method for detecting vertical defects inside a multilayer solid medium composite material of the present invention is characterized in that the specific detection steps are as follows:

[0010] Step 1), measuring the longitudinal wave sound velocity CL1 of the ultrasonic wave in the solid medium 1 and the longitudinal wave sound velocity CL2 of the ultrasonic wave in the solid medium 2;

[0011] Step 2), according to formula (I), calculate the refraction angle β of the sound beam in the solid medium so that the incident wave can excite the creeping wave at the interface;

[0012] β=arcsin(CL1 / CL2)(Ⅰ)

[0013] Step 3), calculating the incident angle α of the ultrasonic creeping wave probe according to β calculated in step 2), and then designing and manufacturing the required wedge inclination angle according to the incident angle α, and determining the probe chip size and frequency;

[0014] Step 4), combining the ultrasonic creeping wave probe and the receiving probe into a probe group;

[0015] Step 5), install the probe group on the detection system, connect the probe group to the ultrasonic flaw detector with a cable, place the inspected part on the workbench of the detection system, and adjust the probe group to the inspected area;

[0016] Step 6) Automatic scanning: If it is a ring-shaped workpiece, a spiral scanning motion mode is adopted, with the W axis as the rotation axis and the X axis as the stepping axis, so that the probe group starts scanning from the starting point until the spiral scanning area completely covers the inspected area, and the scanning pitch ΔX1=0.1~1mm; if it is a plate-shaped workpiece, an XY two-dimensional scanning motion mode is adopted, with the Y axis as the scanning axis and the X axis as the stepping axis, so that the XY two-dimensional scanning area completely covers the inspected area, and the scanning step ΔX2=0.1~1mm;

[0017] Step 7) Ultrasonic excitation and instrument parameter setting: while scanning in step 6), start the ultrasonic flaw detector to synchronously excite the creeping wave probe in the probe group to emit ultrasonic waves;

[0018] Step 8) Collection of defect echo signals: When the ultrasonic wave emitted by the probe in step 7) encounters a heterogeneous interface, it will be converted into a creeping wave. When the creeping wave encounters a vertical defect, a diffraction wave will be emitted. The diffraction wave signal is received by the receiving probe, and then converted into an electrical signal and collected by the ultrasonic flaw detector. The signal is then uploaded to the host computer for storage;

[0019] Step 9) The signals stored in the computer are post-processed to finally display the results in A scan, B scan and C scan.

[0020] As the preferred technical solution:

[0021] In step 3), the probe chip width is 10 to 15 mm, and the chip frequency range is 1 MHz to 15 MHz.

[0022] In step 4), the distance between the ultrasonic creeping wave probe and the receiving probe is adjusted, and the distance is set to 1 to 3 times the distance between the detected surface and the heterogeneous interface.

[0023] In step 7), the repetition frequency of ultrasonic excitation is related to the Y-axis scanning speed. The linear speed of the Y-axis shall not be greater than 150 mm / s, and the repetition frequency of ultrasonic excitation is 100 Hz to 10 kHz. The setting of instrument gain mainly depends on the detection sensitivity, and can be adjusted with reference to the comparison test block used in conventional ultrasonic testing to make the artificial defect echo reach the wave height required for the benchmark sensitivity. The starting position of the instrument gate is set at about 5 to 10 mm after the longitudinal wave p1p2p1 to exclude pseudo-defect interference waves that affect detection.

[0024] The method of the present invention has a wide range of applications and can accurately detect vertical defects inside thicker materials. The method is particularly suitable for multilayer solid dielectric materials with a thickness of 10 mm to 100 mm.

[0025] The present invention also provides a detection device dedicated to the method, characterized in that: the detection device is composed of a probe group 14 and a three-dimensional automatic scanning device, wherein:

[0026] The probe group 14 is composed of a creeping wave probe 2 and a receiving probe 3, which are combined together by a fixture module 19;

[0027] The three-dimensional automatic scanning device includes a detection water tank 6, an XYZ axis motion mechanism, a cable 9, an ultrasonic flaw detector 10, an industrial computer 11, an electrical control device 12, a positioning fixture 15, and a W-axis rotation motion device 16; the detection water tank 6 is provided with an XYZ axis motion mechanism and a W-axis rotation motion device 16, and the positioning fixture 15 is arranged on the W-axis rotation motion device 16; the probe group 14 is fixed on the XYZ axis motion mechanism and is connected to the ultrasonic flaw detector 10 through the cable 9; the industrial computer 11 is connected to the ultrasonic flaw detector 10 and the electrical control device 12.

[0028] In terms of scanning motion function, the device can provide XY two-dimensional plane scanning and W-axis rotation motion; in terms of instrument function, the device can realize ultrasonic excitation and reception, and collect and save the full waveform of ultrasonic signals. In terms of signal data post-processing, the device has A-scan, B-scan, C-scan display functions and time domain-frequency domain conversion analysis functions.

[0029] The present invention has the following advantages:

[0030] The present invention utilizes the multi-interface structural characteristics and ultrasonic creeping wave propagation characteristics of composite materials to establish a detection system consisting of a specially designed ultrasonic probe group and a three-dimensional automatic scanning device, and formulates a unique detection process method to achieve non-destructive detection of vertical defects inside composite materials with multi-layer solid medium characteristics such as integral blade ring (Ti-MMC) components. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of detection principle;

[0032] Figure 2 Testing process flow chart;

[0033] Figure 3 It is a structural principle diagram of a detection device for a method for detecting vertical defects inside a multi-layer solid dielectric material according to the present invention;

[0034] Figure 4 Schematic diagram of the probe group structure;

[0035] Figure 5 Structural diagram of fiber-reinforced titanium-based composite panels with artificial defects;

[0036] Figure 6 C-scan display of the test results of fiber-reinforced titanium-based composite panels;

[0037] Figure 7 Copper-aluminum composite conductive electrode plate;

[0038] Figure 8 The test results of the copper and aluminum conductive electrode plates are displayed in C scan.

[0039] Figure numerals: 1. solid medium one, 2. creeping wave probe, 3. receiving probe, 4. microcrack, 5. solid medium two, 6. detection water tank, 7. X-axis linear motion device, 8. Y-axis linear motion device, 9. cable, 10. ultrasonic flaw detector, 11. industrial computer, 12. electrical control device, 13. Z-axis linear motion device, 14. probe group, 15. positioning fixture, 16. W-axis rotation motion device, 17. wafer, 18. wedge block, 19. fixture module, 20. artificial groove defect. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with the embodiments.

[0041] Example 1

[0042] See also Figure 1 , the material to be tested is a fiber-reinforced metal matrix composite material structure, which has a layered composite structure composed of a matrix alloy material (solid medium 1) and a reinforcing fiber material (solid medium 2 5). Since the matrix alloy material and the reinforcing fiber material are media with different densities and sound velocities, a heterogeneous interface AB`BB`` with different acoustic properties will be formed. The creeping wave probe 2 excites a refracted longitudinal wave P1 in the matrix alloy, and when it is incident on the heterogeneous interface AB`BB`` at an appropriate angle β, it will excite a creeping wave p1p2 on the interface AB`BB``. When the creeping wave p1p2 propagates along the interface AB`BB``, it will radiate a longitudinal wave p1p2p1 and a head wave p1p2s1 into the solid medium 1, and at the same time radiate a head wave p1p2s2 into the solid medium 2 5. When the creeping wave p1p2 "collides" with the microcrack 4 perpendicular to the direction of the reinforcing fiber material, a diffraction wave will be generated, and then the receiving probe 3 will receive this diffraction wave to implement detection.

[0043] like Figure 3 , 4 As shown, the detection device is composed of a probe group 14 and a three-dimensional automatic scanning device, wherein:

[0044] The probe group 14 is composed of a creeping wave probe 2 and a receiving probe 3, which are combined together by a fixture module 19. In this embodiment, the receiving probe 3 is an immersion probe, and the creeping wave probe 2 is a contact creeping wave probe;

[0045] The three-dimensional automatic scanning device includes a detection water tank 6, an XYZ axis motion mechanism, a cable 9, an ultrasonic flaw detector 10, an industrial computer 11, an electrical control device 12, a positioning fixture 15, and a W-axis rotation motion device 16; the detection water tank 6 is provided with an XYZ axis motion mechanism and a W-axis rotation motion device 16, and the positioning fixture 15 is arranged on the W-axis rotation motion device 16; the probe group 14 is fixed on the XYZ axis motion mechanism and is connected to the ultrasonic flaw detector 10 through the cable 9; the industrial computer 11 is connected to the ultrasonic flaw detector 10 and the electrical control device 12.

[0046] The XYZ axis motion mechanism includes an X-axis linear motion device 7, a Y-axis linear motion device 8 and a Z-axis linear motion device 13, forming a "gantry" type three-dimensional scanning mechanism, and the three motion axes all have a position recording function; the W-axis rotation motion device 16 is located below the water surface of the detection water tank 6 and has a position recording function; the probe group 14 is a component composed of two independent ultrasonic probes installed on a fixture module 19, one probe excites ultrasonic creeping waves, and one probe receives diffraction waves; the ultrasonic flaw detector 10 is connected to the probe group 14 through a coaxial cable 9, has ultrasonic emission and reception functions, and converts ultrasonic signals into electrical signals, and uploads the signals to the industrial computer 11 through an A / D converter.

[0047] Ultrasonic testing of continuous fiber reinforced metal matrix composites includes the following steps:

[0048] Step 1), the longitudinal wave sound velocity CL1 of the ultrasonic wave in the matrix alloy material (solid medium 1) is measured to be 6100 m / s, and the longitudinal wave sound velocity CL2 along the axial direction of the reinforcing fiber material (solid medium 2 5) is measured to be 7969 m / s, see Figure 1 ;

[0049] Step 2) Calculate the refraction angle of the acoustic beam in the alloy according to formula (I) β≈49° to ensure that creeping waves are excited at the interface between the alloy and the fiber.

[0050] Step 3), the embodiment adopts the contact type creeping wave probe form, calculates the incident angle α of the ultrasonic wave in the probe according to the β angle obtained in step 2), and designs and manufactures the creeping wave probe 2 for exciting the ultrasonic creeping wave, the inclination angle α of the wedge 18 is 20°, the size of all the wafers 17 of the probe is about 10x10mm, the wafer frequency is 5MHz, see Figure 4 .

[0051] Step 4), install the creeping wave probe 2 and the receiving probe 3 in the fixture module 19 to form a probe group 14, and the distance between the two probes is 30 mm, see Figure 4 ;

[0052] Step 5), install the probe group 14 on the detection device, connect the probe group 14 to the ultrasonic flaw detector 10 with the cable 9, place the SiC fiber reinforced Ti-based composite material to be detected on the positioning fixture 15 of the detection device workbench, make the probe group 14 contact with the surface of the material to be detected, and adjust the probe to the area where the fiber core is located.

[0053] Step 6) Automatic scanning: Move the probe to the edge of the fiber area as the scanning starting point.

[0054] Since the workpiece to be inspected in the embodiment is a plate-shaped workpiece, an XY two-dimensional scanning motion mode is adopted. The scanning axis Y axis moves in a straight line parallel to the fiber axis, and the stepping axis X axis moves in a perpendicular fiber direction. The stepping interval ΔX2 = 0.1 mm is set so that the XY two-dimensional scanning area completely covers the area where the fiber core is located. Figure 5 .

[0055] Step 7) Instrument parameter setting and ultrasonic excitation: While scanning in step 6), start the ultrasonic flaw detector 10 to synchronously excite the creeping wave probe 2 to emit ultrasonic waves. The repetition frequency of ultrasonic excitation is related to the Y-axis scanning speed. The linear speed of the Y-axis is set to 150 mm / s, and the repetition frequency of ultrasonic excitation is set to 5 kHz; the instrument gain is 53 dB, and the gate starting position is set 5 to 10 mm after the longitudinal wave p1p2p1.

[0056] Step 8) Collection of defect echo signals: When the ultrasonic wave emitted by the creeping wave probe 2 in step 7) encounters the interface between the alloy and the fiber, it will be converted into a creeping wave. When the creeping wave encounters a fiber break defect, a diffraction wave will be emitted. The diffraction wave signal is received by the receiving probe 3 and converted into an electrical signal, which is collected by the ultrasonic flaw detector 10 and uploaded to the host computer 11 as a defect signal for storage.

[0057] Step 9) The result analysis software in the host computer 11 performs data post-processing on the stored ultrasonic signal, identifies the defect wave signal, and finally realizes the C-scan display of the result, see Figure 6 .

[0058] The test workpiece is a sample with prefabricated defects, in which there are 9 layers of reinforcing fiber filaments. The fiber surface broken wire defect A is prefabricated on the upper three layers of the sample; the fiber internal broken wire defect B is prefabricated on the middle three layers of the sample; and the fiber bottom broken wire defect C is prefabricated on the lower three layers of the sample. Figure 5 . Figure 6The middle is the C scan image display of the test result. The "horizontal lines" at ABC in the figure are three fiber breakage prefabrication defects in the above sample. After measurement, the distances from A, B and C in the test result figure to one end of the sample are 37.84, 72.68 and 111.78 mm, which are basically consistent with the prefabrication defect positions of the sample design, indicating that the present invention can effectively detect all defects.

[0059] Example 2

[0060] See also Figure 7 The workpiece under test is a copper-aluminum composite conductive plate with a total thickness of 78 mm. The sandwich solid medium is an aluminum alloy with a thickness of 18 mm. An artificial groove defect 20 is provided in the aluminum alloy with a size of 10×40×0.2 mm (length×depth×width).

[0061] The detection steps refer to Example 1, wherein the setting of the instrument parameters in step 7) has a gain value of 62dB.

[0062] The C scan of the test results is shown as follows: Figure 8 As shown, the image display position is consistent with the actual processing defect position.

[0063] Matters not covered by the present invention are known technologies.

[0064] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting vertical defects inside a multi-layer solid dielectric material, characterized in that: The acoustic difference between two solid media forms a boundary effect. The detection is based on the characteristic that when ultrasonic creeping waves propagate along heterogeneous interfaces and encounter defects, they will stimulate diffraction waves. Specifically, a creeping wave probe and a receiving probe are used to form a probe group. The creeping wave probe emits ultrasonic creeping waves, and the receiving probe receives the diffraction waves and converts them into electrical signals, thereby implementing the detection. The specific steps are as follows: Step 1), measuring the longitudinal wave sound velocity CL1 of the ultrasonic wave in the solid medium 1 and the longitudinal wave sound velocity CL2 of the ultrasonic wave in the solid medium 2; Step 2), according to formula (I), the refraction angle β of the acoustic beam in the solid medium 1 is calculated so that the incident wave can excite a creeping wave at the interface between the solid medium 1 and the solid medium 2; β=arcsin(CL1 / CL2) (Ⅰ) Step 3), calculating the incident angle α of the ultrasonic creeping wave probe according to the β calculated in step 2), and then designing and manufacturing the required wedge inclination angle according to the incident angle α, and determining the probe chip size and frequency; Step 4), combining the ultrasonic creeping wave probe and the receiving probe into a probe group; Step 5), install the probe group on the detection system, connect the probe group to the ultrasonic flaw detector with a cable, place the inspected part on the workbench of the detection system, and adjust the probe group to the inspected area; Step 6) Automatic scanning: If it is a ring-shaped workpiece, a spiral scanning motion mode is adopted, with the W axis as the rotation axis and the X axis as the stepping axis, so that the probe group starts scanning from the starting point until the spiral scanning area completely covers the inspected area, and the scanning pitch ΔX1=0.1~1mm; if it is a plate-shaped workpiece, an XY two-dimensional scanning motion mode is adopted, with the Y axis as the scanning axis and the X axis as the stepping axis, so that the XY two-dimensional scanning area completely covers the inspected area, and the scanning step ΔX2=0.1~1mm; Step 7) Ultrasonic excitation and instrument parameter setting: while scanning in step 6), start the ultrasonic flaw detector to synchronously excite the creeping wave probe in the probe group to emit ultrasonic waves; Step 8) Collection of defect echo signals: When the ultrasonic wave emitted by the probe in step 7) encounters a heterogeneous interface, it will be converted into a creeping wave. When the creeping wave encounters a vertical defect, a diffraction wave will be emitted. The diffraction wave signal is received by the receiving probe, and then converted into an electrical signal and collected by the ultrasonic flaw detector. The signal is then uploaded to the host computer for storage; Step 9) The signals stored in the computer are post-processed to finally display the results in A scan, B scan and C scan.

2. The method for detecting vertical defects inside a multilayer solid dielectric material according to claim 1, characterized in that: The multi-layer solid dielectric material is a layered composite structure composed of two or more materials with acoustic impedance values ​​differing by more than 20%, and the defect type to be detected is a vertical defect inside the composite material perpendicular to the detection surface.

3. The method for detecting vertical defects inside a multilayer solid dielectric material according to claim 1, characterized in that: The refraction angle β of the sound beam needs to be calculated according to the ultrasonic sound velocity in each component solid medium so that the incident wave can excite the creeping wave at the interface, and the inclination angle of the creeping wave probe is designed according to the refraction angle β.

4. The method for detecting vertical defects inside a multi-layer solid dielectric material according to claim 1, characterized in that: In step 3), the probe chip width is 10 to 15 mm, and the chip frequency range is 1 MHz to 15 MHz.

5. The method for detecting vertical defects inside a multi-layer solid dielectric material according to claim 1, characterized in that: In step 4), the distance between the ultrasonic creeping wave probe and the receiving probe is adjusted, and the distance is set to 1 to 3 times the distance between the detected surface and the heterogeneous interface.

6. The method for detecting vertical defects inside a multi-layer solid dielectric material according to claim 1, characterized in that: In step 7), the repetition frequency of ultrasonic excitation is related to the Y-axis scanning speed. The linear speed of the Y-axis shall not be greater than 150 mm / s, and the repetition frequency of ultrasonic excitation is 100 Hz to 10 kHz. The starting position of the instrument gate is set 5 to 10 mm after the longitudinal wave p1p2p1 to eliminate pseudo-defect interference waves that affect detection.

7. The method for detecting vertical defects inside a multilayer solid dielectric material according to any one of claims 1 to 6, characterized in that: The thickness of the multi-layer solid medium material is 10 mm to 100 mm.

8. A dedicated detection device for implementing the method of claim 1, characterized in that: The detection device is composed of a probe group (14) and a three-dimensional automatic scanning device, wherein: The probe group (14) is composed of a creeping wave probe (2) and a receiving probe (3), which are combined together through a fixture module (19); The three-dimensional automatic scanning device comprises a detection water tank (6), an XYZ axis motion mechanism, a cable (9), an ultrasonic flaw detector (10), an industrial computer (11), an electrical control device (12), a positioning fixture (15), and a W-axis rotation motion device (16); the detection water tank (6) is provided with an XYZ axis motion mechanism and a W-axis rotation motion device (16), and the positioning fixture (15) is arranged on the W-axis rotation motion device (16); the probe group (14) is fixed on the XYZ axis motion mechanism and is connected to the ultrasonic flaw detector (10) through the cable (9); the industrial computer (11) is connected to the ultrasonic flaw detector (10) and the electrical control device (12).

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