Ultrasonic dry-coupled roller probe and detection method

Abstract

The present invention relates to an ultrasonic dry-coupled roller probe and a detection method, belonging to the field of non-destructive testing technology, and solves the problem in the prior art that a single-side single probe cannot be used for detection and that longitudinal crack defects cannot be detected. The present invention provides an ultrasonic dry-coupled roller probe, comprising a first wafer and a second wafer that are parallel and arranged adjacent to each other at their ends; the first wafer is provided with a delamination defect detection area and a crack defect detection area; the crack defect detection area of ​​the first wafer is provided with a first wedge block close to the side of the inspected part, and the second wafer is provided with a second wedge block close to the side of the inspected part; the ultrasonic signal of the delamination defect detection area of ​​the first wafer is used to detect the delamination defect of the inspected part, and the ultrasonic signals of the crack defect detection area of ​​the first wafer and the second wafer are used to detect the crack defect of the inspected part, thereby realizing a single-time, single-side, single-probe, rapid and accurate ultrasonic detection of delamination and crack defects of a composite material antenna cover.

Description

Technical Field

[0001] The present invention relates to the technical field of nondestructive testing, and in particular to an ultrasonic dry-coupled roller probe and a testing method. Background Art

[0002] During use, radomes are subject to high-temperature, high-velocity airflow. Internal defects can degrade the mechanical properties of the product and even cause material fracture, leading to serious accidents. Therefore, effective non-destructive testing techniques must be used to inspect the internal quality of composite radomes.

[0003] Currently, ultrasonic testing is the most commonly used and effective nondestructive testing method for composite materials. Most existing ultrasonic probes require the use of a liquid couplant between the probe and the surface of the test piece. However, new composite radomes, made from reinforced fibers, a high-temperature resin matrix, and wave-transmitting or stealthy materials through processes such as weaving and resin transfer molding, exhibit high porosity, significantly attenuating ultrasonic signals and preventing conventional ultrasonic probes from penetrating them. Furthermore, these composite surfaces are impervious to liquid couplant, making them impractical for testing with conventional liquid-coupled ultrasonic probes.

[0004] In addition, this composite material antenna cover is prone to transverse delamination defects parallel to the layup direction and longitudinal crack defects perpendicular to the layup direction. The ultrasonic probe in the existing technology can only detect transverse delamination defects, and detects delamination defects through dual probes on both sides. It is impossible to use a single probe on one side for detection, let alone longitudinal crack defects.

[0005] Therefore, in order to improve detection efficiency and ensure detection accuracy, there is an urgent need for an ultrasonic probe and a detection method that can simultaneously detect transverse delamination defects and longitudinal crack defects with a single probe on a single side. Summary of the Invention

[0006] In view of the above analysis, the present invention aims to provide an ultrasonic dry-coupled roller probe and detection method, which can solve at least one of the following technical problems: (1) The composite antenna cover has a large porosity and greatly attenuates the ultrasonic signal. Conventional ultrasonic detection methods cannot penetrate the composite antenna cover; (2) The surface of the composite antenna cover material is not allowed to contact the liquid coupling agent, and conventional liquid-coupled ultrasonic detection cannot be used; (3) The composite antenna cover material is prone to delamination parallel to the laying direction and longitudinal cracks perpendicular to the laying direction. Conventional ultrasonic detection probes can only detect delamination defects using double-sided dual probes, and cannot use single-sided single probe detection; (4) Conventional ultrasonic probes cannot detect longitudinal crack defects.

[0007] The purpose of the invention is mainly achieved through the following technical solutions:

[0008] In one aspect, the present invention provides an ultrasonic dry-coupled roller probe comprising a first wafer and a second wafer that are parallel and disposed adjacent to each other at their ends;

[0009] The first wafer is provided with a delamination defect detection area and a crack defect detection area;

[0010] A first wedge is provided on the crack defect detection area of ​​the first wafer near the inspected object, and a second wedge is provided on the second wafer near the inspected object;

[0011] The ultrasonic signal of the delamination defect detection area of ​​the first wafer is used to detect delamination defects of the inspected object, and the ultrasonic signal of the crack defect detection area of ​​the first wafer and the second wafer is used to detect crack defects of the inspected object.

[0012] Furthermore, the length ratio of the first wafer to the second wafer is 2:1;

[0013] The ratio of the length of the delamination defect detection area and the crack defect detection area of ​​the first wafer to the length of the second wafer is 1:1:1.

[0014] Furthermore, the center frequency of the first chip is greater than the center frequency of the second chip.

[0015] Furthermore, the first wedge block and the second wedge block are axially symmetrically distributed, and the axis of symmetry is the boundary line between the first wafer and the second wafer.

[0016] Furthermore, the cross-sections of the first wedge block and the second wedge block are both right triangles, the first right-angled sides of the first wedge block and the second wedge block are connected to the wedge block mounting surface of the corresponding chip; the second right-angled sides of the first wedge block and the second wedge block are perpendicular to the wedge block mounting surface of the corresponding chip; the hypotenuses of the two right triangles form a Λ shape.

[0017] Furthermore, the probe further comprises a cylinder with closed ends and a cylinder rolling connection structure, the first wafer and the second wafer are arranged in the cylinder, and the cylinder is filled with coupling agent;

[0018] When the cylinder rolls, the first wafer and the second wafer remain stationary relative to the axial direction of the cylinder, and the cylinder and the surface of the inspected object are scanned through close rolling friction.

[0019] Furthermore, the thickness of the coupling agent layer on the DUT side of the delamination defect detection area of ​​the first wafer should meet the following requirements:

[0020]

[0021] Among them, L 耦合剂 -Thickness of the coupling agent layer, C 耦合剂 - longitudinal wave velocity in the couplant, T 被检件 -Thickness of the test piece, C被检件 -Longitudinal wave velocity in the test piece.

[0022] Furthermore, the first wedge block and the second wedge block both satisfy the following formula:

[0023]

[0024] β + θ = α Formula 2

[0025]

[0026] Among them, C 楔块材质 is the speed of longitudinal waves in the wedge;

[0027] C 耦合剂 is the longitudinal wave velocity in the couplant;

[0028] C 兰姆波 is the Lamb wave speed in the test piece, where the Lamb wave is a transversely propagating sound wave;

[0029] θ is the angle between the propagation direction of the ultrasonic signal after it changes direction and the original propagation direction;

[0030] α is the angle between the hypotenuse of the wedge and the wedge mounting surface of the corresponding wafer;

[0031] β is the angle between the propagation direction of the ultrasonic signal after it changes direction and the vertical line of the hypotenuse of the wedge.

[0032] On the other hand, the present invention also provides an ultrasonic dry-coupling detection method for a radome, including delamination defect detection and / or crack defect detection;

[0033] Delamination defect detection includes: emitting ultrasonic waves from the delamination defect detection area of ​​the first wafer. The ultrasonic waves propagate longitudinally to the test piece. After being reflected by the bottom surface of the test piece, the ultrasonic signals return along the original path and are received by the first wafer. If the ultrasonic signal response is abnormal, it is determined that a transverse delamination defect exists within the test piece at that location.

[0034] Crack defect detection includes: the crack defect detection area of ​​the first chip emits ultrasonic waves, which are changed in propagation direction by the first wedge and become transverse waves when entering the test piece. After passing through the test piece, they follow a symmetrical path and then pass through the second wedge, changing to the original propagation direction and being received by the second chip. If there is an abnormal ultrasonic signal at this time, it indicates that there is a longitudinal crack defect at this position inside the test piece.

[0035] Furthermore, the above detection step includes:

[0036] Step 1: Set artificial simulated defects inside the reference test block, and the material and thickness of the reference test block are the same as those of the test piece;

[0037] Step 2: Set the ultrasound instrument's channel A to reflection mode and channel B to penetration mode, and synchronize them; connect the ultrasound high-dry coupling roller probe port to the ultrasound instrument;

[0038] Step 3: Adjust the gain values ​​of channels A and B. When the ultrasonic high-dry coupling roller probe is placed at a non-defective area, the ultrasonic signal amplitude is no less than 100%. When the ultrasonic high-dry coupling roller probe is placed at the center of the artificially simulated defect, the amplitude of the ultrasonic reflection signal is no more than 20%.

[0039] Step 4: Scan the inspected part in a grid-type scanning mode. The scanning direction is consistent with the direction of the probe roller diameter, and the scanning step is half of the second element of the ultrasonic high-dry coupling roller probe.

[0040] Step 5: During scanning, when the amplitude of the ultrasonic signal of channel A is no more than 20% and is at its lowest, the location of the delamination defect is below the center position of the delamination defect area of ​​the first wafer; when the amplitude of the ultrasonic signal of channel B is no more than 20% and is at its lowest, the location of the longitudinal crack is below the boundary line between the first wafer and the second wafer.

[0041] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0042] 1. The ultrasonic dry-coupled roller probe of the present invention comprises a first wafer and a second wafer arranged parallel to each other with adjacent ends. The first wafer includes a delamination defect detection area and a crack defect detection area, while the second wafer receives only crack detection signals. The ultrasonic signal from the delamination defect detection area of ​​the first wafer is used to detect delamination defects in the test object. Wedges are symmetrically arranged near the side of the crack defect detection area of ​​the first wafer and the second wafer adjacent to the test object to change the propagation direction of the ultrasonic signal, thereby allowing the ultrasonic signals from the crack defect detection area of ​​the first wafer and the second wafer to detect crack defects in the test object. This invention achieves the first single-shot, single-side, single-probe ultrasonic detection of delamination and crack defects in composite radomes.

[0043] 2. The ultrasonic detection probe of the present invention changes the propagation direction of the ultrasonic signal by bonding a triangular wedge to the front end of the ultrasonic transmitting chip, converting the longitudinal wave into a transverse wave, which is used to detect longitudinal crack defects, filling the gap that ultrasonic detection probes cannot detect longitudinal cracks.

[0044] 3. The ultrasonic dry-coupled roller probe of the present invention uses two chips with different center frequencies. The high-frequency chip can ensure high resolution when detecting delamination defects, and the low-frequency chip can ensure high sensitivity when detecting crack defects.

[0045] 4. The ultrasonic dry-coupled roller probe of the present invention determines the thickness of the coupling agent to ensure that the multiple ultrasonic reflection waves of the coupling agent during detection are after the reflection waves on the surface of the antenna cover, so that the secondary ultrasonic reflection waves of the coupling agent layer will not affect the ultrasonic reflection signal of the test object, thereby improving the accuracy of detection.

[0046] 5. The ultrasonic dry-coupled roller probe and detection method of the present invention ensure the detection sensitivity of the first wafer and the second wafer for delamination and crack defects by calibrating the sensitivity of the ultrasonic instrument, further improving the accuracy of the detection results.

[0047] 6. The ultrasonic dry-coupled roller probe and detection method of the present invention do not require the use of any liquid coupling agent on the surface of the test piece during scanning, thus preventing the coupling agent from causing irreversible contamination of the composite material. As can be seen from the comparative examples, the prior art uses water as a coupling agent, which has a certain impact on the detection results, resulting in a detection error of more than 30%. The detection error of the present invention is less than 10%, thereby improving detection accuracy.

[0048] 7. The ultrasonic dry-coupled roller probe and detection method of the present invention adopt a grid scanning method, the scanning direction is consistent with the direction of the probe roller diameter, and the scanning step is half of the second chip size of the probe (such as the radius), ensuring that no detection is missed, and delamination defects and crack defects are detected at the same time, greatly improving the detection efficiency and saving time and cost.

[0049] 8. The ultrasonic dry-coupled roller probe and detection method of the present invention, through actual detection of embodiments and comparative examples, compared with the prior art, the detection lower limit of the present invention is 4 mm. Compared with the detection lower limit of 10 mm of the existing device, the probe and detection method provided by the present invention have lowered the detection lower limit.

[0050] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of the present invention will be described in the following description, and some advantages will become apparent from the description or be learned through practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0052] Figure 1 A cross-sectional view of the structure of an ultrasonic dry-coupled roller probe provided in an embodiment of the present invention;

[0053] Figure 2 Schematic diagram of the detection device provided in Example 1 of the present invention;

[0054] Figure 3 Schematic diagram of the relationship between the acute angle formed by the wedge and the wafer in the probe of the present invention and the direction of ultrasonic wave propagation;

[0055] Figure 4 A schematic diagram of ultrasonic detection of delamination defects according to an embodiment of the present invention;

[0056] Figure 5 Schematic diagram of ultrasonic detection of crack defects according to an embodiment of the present invention.

[0057] Reference numerals:

[0058] 1-Probe B interface; 2-Probe A interface; 3-Handle; 4-Spring; 5-First chip; 6-Second chip; 7-First wedge; 8-Second wedge; 9-Wheel disc; 10-Sealing ring; 11-Bearing; 12-Shaft; 13-Rubber tire; 14-Couplant layer thickness; 15-Receiving end of ultrasonic instrument B channel; 16-Transmitting end of ultrasonic instrument A channel; 17-Probe connection line; 18-Ultrasonic dry-coupling roller probe; 19-Multi-channel ultrasonic instrument. DETAILED DESCRIPTION

[0059] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0060] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the term "connection" should be understood in a broad sense. For example, it can refer to a fixed connection, a detachable connection, or an integral connection. It can also refer to a mechanical connection, an electrical connection, a direct connection, or an indirect connection through an intermediate medium. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0061] The terms "surface," "bottom," "above," "below," and "on" used throughout this document refer to relative positions relative to the layered structure of the inspected portion of the radome, for example, the relative positions of the surface and bottom of the radome. It should be understood that the inspected portion of the radome is a layered structure, regardless of its orientation in space.

[0062] The working surface of the present invention can be a plane or a curved surface, can be inclined, or can be horizontal. For the convenience of description, the embodiment of the present invention is placed on a horizontal surface and used on the horizontal surface, and "high and low" and "up and down" are defined in this way.

[0063] The present invention discloses an ultrasonic dry-coupled roller probe, such as Figure 1As shown, it includes a first chip 5 and a second chip 6 arranged in parallel with adjacent ends; wherein, the first chip includes a delamination defect detection area and a crack defect detection area; the crack defect detection area of ​​the above-mentioned first chip is provided with a first wedge block 7, and the second chip is provided with a second wedge block 8; the ultrasonic signal of the delamination defect detection area of ​​the first chip is used to detect the delamination defect of the test piece, and the ultrasonic signals of the crack defect detection area of ​​the first chip and the second chip are used to detect the crack defect of the test piece.

[0064] The number of chips in existing roller probes is mostly one, but there are also multiple chips. However, the sizes of the chips are all the same, and they can only detect delamination defects, but not crack defects. The present invention uses a first chip and a second chip that are arranged in parallel and adjacent to each other at the ends, and the sizes of the first chip and the second chip are different. At the same time, a delamination defect detection area and a crack defect detection area are set on the first chip. The ultrasonic signal of the delamination defect detection area of ​​the first chip is used to detect the delamination defects of the inspected part, and the area of ​​the second chip is set as the crack defect detection area. The ultrasonic signals of the crack defect detection area of ​​the first chip and the second chip are used to detect the crack defects of the inspected part. The present invention arranges the first chip and the second chip of the dry-coupled roller probe on the same side, and the first chip has an area for detecting delamination defects. The delamination defects in the composite antenna cover are detected by transmitting and receiving ultrasonic signals in this area of ​​the chip, which can realize single-side single-probe ultrasonic detection of delamination defects. At the same time, a wedge is set on the side of the chip close to the inspected part, and under the action of the wedge, it can realize single-side single-probe detection of longitudinal crack defects.

[0065] Along the parallel direction of the first and second wafers, the ratio of the lengths of the delamination defect detection area to the crack defect detection area is 1:2. In other words, the crack defect detection area is located on both the first and second wafers, and the delamination defect detection area and part of the crack defect detection area of ​​the first wafer are located on the same wafer. This satisfies the requirement of cooperating on two wafers for defect detection and improves detection sensitivity.

[0066] In order to realize the detection of delamination defects and longitudinal crack defects on the same side (i.e., single side) and with the same probe at the same time, the wafers are arranged in parallel with the first wafer and the second wafer being arranged adjacent to each other at the ends; wherein the first wafer includes a delamination defect detection area and a crack defect detection area; wherein the crack defect detection area of ​​the first wafer and the second wafer are symmetrically provided with wedges close to the side of the inspected piece, that is, the crack defect detection area of ​​the first wafer is provided with a first wedge 12 close to the side of the inspected piece, and the crack defect detection area of ​​the second wafer is provided with a second wedge 13 close to the side of the inspected piece, and the symmetry axis of the first wedge 12 and the second wedge 13 is the dividing line between the first wafer and the second wafer.

[0067] During operation, the delamination defect detection area of ​​the first wafer emits ultrasonic waves, which propagate longitudinally to the inspected object. After being reflected by the bottom surface of the inspected object, the ultrasonic signal returns along the original path and is received by the first wafer.

[0068] The crack defect detection area of ​​the first chip emits ultrasonic waves, which change the propagation direction after the first wedge block and enter the test piece as shear waves. After passing through the test piece, it follows a symmetrical path and passes through the second wedge block at the front end of the second chip and is received by the second chip.

[0069] When detecting crack defects, the right half of the first wafer, i.e., the crack defect detection area of ​​the first wafer, is used to transmit energy, and the crack defect detection area of ​​the second wafer, i.e., the second wafer, is used to receive energy. To ensure the same size of the transmitted and received acoustic beams, the length of the crack defect detection area of ​​the first wafer is equal to the length of the second wafer, and the size of the left half of the first wafer is equal to the size of the right half. In other words, the length of the second wafer is half the length of the first wafer.

[0070] Specifically, the ratio of the lengths of the delamination defect detection area and the crack defect detection area of ​​the first wafer is 1:1; the ratio of the lengths of the delamination defect detection area and the crack defect detection area of ​​the first wafer to the lengths of the second wafer is 1:1:1.

[0071] Then, along the direction in which the first wafer and the second wafer are arranged in parallel, the ratio of the lengths of the delamination defect detection area to the crack defect detection area is 1:2; and the ratio of the lengths of the first wafer to the second wafer is 2:1.

[0072] In order to enable single-side single-probe detection of longitudinal crack defects, specifically, the crack defect detection area of ​​the first chip is provided with a first wedge block near the side of the inspected piece, and the second chip is provided with a second wedge block near the side of the inspected piece; the first wedge block and the second wedge block are axially symmetrically distributed, and the axis of symmetry is the dividing line between the first chip and the second chip; the cross-section of the first wedge block and the second wedge block is a right triangle, one of the right-angled sides is connected to the chip, and the two oblique sides of the two wedge blocks are relatively distributed.

[0073] To ensure the propagation path of the ultrasonic wave, the length of a right-angled side connecting the two wedges to the wafer is equal to the side length of the wafer in the connected area, that is, the ratio of the length of a right-angled side connecting the wedge to the wafer to the length of the delamination defect detection area and crack defect detection area of ​​the first wafer and the length of the second wafer is 1:1:1:1.

[0074] It's important to note that sound waves at the ultrasonic frequencies commonly used in nondestructive testing (NDT) cannot propagate effectively in air. Besides attenuating the signal, air's acoustic impedance is also highly mismatched with typical test materials. Even the narrowest air gap between the probe and the test piece can affect the effective transmission of ultrasonic waves, making conventional testing impossible.

[0075] Therefore, a sealing elastic medium filled with ultrasonic coupling agent is provided outside the wafer.

[0076] Specifically, liquid coupling agent has its own sound velocity. During delamination defect detection, within a very short distance, the ultrasonic signal passes through the coupling agent and then enters the test piece. However, there will also be some reflected signals at the boundary between the coupling agent and the test piece. If these secondary reflected signals are received by the wafer before the reflection signal from the bottom surface of the test piece, or if they are superimposed on the reflection signal from the bottom surface of the test piece, they will affect the detection signal. Therefore, the thickness of the coupling agent layer must be such that the secondary ultrasonic reflection wave of the coupling agent is behind the surface reflection wave of the test piece and does not affect the detection signal. The ratio of the thickness of the ultrasonic coupling agent to the longitudinal wave sound velocity in the coupling agent should be greater than the ratio of the thickness of the test piece to the longitudinal wave sound velocity in the test piece. Specifically, the thickness 14 of the coupling agent layer in the first wafer delamination defect detection area of ​​the dry-coupled ultrasonic probe satisfies the formula:

[0077]

[0078] Among them, L 耦合剂 -Thickness of the coupling agent layer, C 耦合剂 - Sound velocity of the couplant, T 被检件 -Thickness of the test piece, C 被检件 -The speed of sound of the test piece.

[0079] When detecting longitudinal crack defects, in order to ensure that the ultrasonic wave propagation path is converted into a transverse wave when entering the test piece, and that the returned sound wave signal can be received by the second chip, preferably at the center of the second chip, the size, angle and material of the wedge must match. Since the cross section of the wedge is a right triangle, the first right-angled side of the wedge and the wedge mounting surface of the corresponding chip are set to α. This angle α and the material of the wedge, as well as how to make the returned ultrasonic signal fall at the center of the second chip, are as follows: Figure 3 As shown, the following formula relationship needs to be satisfied:

[0080]

[0081] β + θ = α Formula 2

[0082]

[0083] The parameters of the wedge can be calculated according to formulas 1, 2, and 3; where;

[0084] C 楔块材质 is the speed of longitudinal waves in a wedge of a certain material;

[0085] C 耦合剂 is the longitudinal wave speed in a certain coupling agent;

[0086] C 兰姆波 is the Lamb wave speed in the test piece, where Lamb wave is a transversely propagating sound wave;

[0087] θ is the angle between the propagation direction of the ultrasonic signal after it changes direction and the original propagation direction;

[0088] α is the angle between the hypotenuse of the wedge and the wedge mounting surface of the corresponding wafer, that is, the first acute angle of the right triangle;

[0089] β is the angle between the propagation direction of the ultrasonic signal after it changes direction and the vertical line of the oblique side (i.e., the longest side) of the wedge.

[0090] Experimental research shows that the low density of the wedge material is conducive to the connection between the wedge and the wafer, and the high sound velocity is conducive to distinguishing the sound velocity of the ultrasonic wave entering the test piece. Preferably, the wedge material is aluminum, which meets the characteristics of low density and high sound velocity.

[0091] For example, the wedge is made of aluminum and the coupling agent is water. The longitudinal wave velocity in aluminum is 6300 m / s, while the longitudinal wave velocity in water is 1500 m / s. The Lamb wave velocity in a composite radome is related to factors such as the ultrasonic frequency and the thickness of the composite material, making it difficult to determine its exact value. Experimental calculations show that the angle α between the hypotenuse of the wedge and the wedge mounting surface of the corresponding wafer (the angle between the hypotenuse of the wedge and the wafer) is 35-55°, which ensures that the second wafer receives the returned ultrasonic signal. If the returned sound wave is positioned at the center of the second wafer, then the angle α formed by the wedge and the wafer is preferably 40°.

[0092] After the positions of the chip and the wedge are determined, the linkage between the chip and the wedge is as follows: the delamination defect detection area of ​​the first chip emits ultrasonic waves, which propagate longitudinally to the test piece. After the ultrasonic signal is reflected by the bottom surface of the test piece, it returns along the original path and is received by the first chip. The abnormality of the ultrasonic signal indicates that there is a horizontal delamination defect inside the test piece at this position.

[0093] The crack defect detection area of ​​the first chip emits ultrasonic waves, which change their propagation direction after being changed by the first wedge and become transverse waves when entering the test piece. After passing through the test piece, they follow a symmetrical path and then pass through the second wedge, returning to their original propagation direction and being received by the second chip. If there is an abnormal ultrasonic signal at this time, it indicates that there is a longitudinal crack defect at this position inside the test piece.

[0094] It's important to note that the center of the wafer is the center of the ultrasonic field, where ultrasonic energy is highest. When the wafer center coincides with the center of the defect, energy is blocked to the greatest extent, with little or no energy propagating to the underside of the test piece. For example, below the contact boundary between the first and second wafers is the intersection of the two wafer acoustic fields, where ultrasonic energy is highest. When this location coincides with the center of the crack defect, energy is blocked to the greatest extent, resulting in the lowest ultrasonic signal amplitude.

[0095] In order to distinguish the signal strength of the two, the center frequency range of the first chip and the second chip is different. The first chip is a high-frequency chip, which can ensure high resolution when detecting delamination defects, and the second chip is a low-frequency chip, which can ensure high sensitivity when detecting crack defects.

[0096] In one possible design, a roller probe is used between the wafer and the test piece to achieve testing. A closed-end cylinder is connected to the cylinder by a rolling mechanism. The wafer is positioned within the cylinder, which is filled with a couplant liquid. Specifically, the cylinder is a sealed elastic medium, which allows the probe's elastic medium to be pressed tightly against the specimen surface during testing, ensuring seamless contact. Exemplarily, the elastic medium is a rubber tire. Specifically, the probe achieves rolling motion via an axial connection, such as a bearing or roller.

[0097] It should be noted that elastic media, such as rubber tires, have a certain attenuation effect on ultrasonic waves, but the thickness of the rubber tires remains consistent. During detection, the ultrasonic waves attenuate uniformly when passing through the rubber tires in the propagation path, so there is no impact on the test results.

[0098] Specifically, as the cylinder rolls, the first and second wafers remain stationary relative to the cylinder's axial direction and are always closest to the test object. In other words, the wafers are perpendicular to the surface of the test object along the wedge direction. This ensures that the sound waves enter the test object vertically. Scanning occurs through close rolling friction between the cylinder and the test object surface, ensuring seamless contact between the elastic medium and the test object. This allows ultrasonic signals to propagate deep into the test object, achieving dry coupling.

[0099] To ensure that the probe is pressed tightly against the surface of the test piece, an elastic device is installed between the upper end of the probe and the handle 3 to ensure coupling pressure, and the maximum pressure of the elastic device is ≥ 25 N. For example, the elastic device is a spring.

[0100] The dry-coupled roller probe uses a bearing 11 to roll a rubber tire 13. Close rolling friction between the tire and the surface of the test piece creates a scan. The wafer and the axis 12 holding the wafer remain stationary and positioned closest to the test piece. This means the wafer is perpendicular to the surface of the test piece along the wedge. This ensures that the sound waves enter the test piece vertically. A mechanical seal 10 is placed between the bearing 11 and the wheel 9 to prevent leakage and contamination of the test piece by the liquid couplant.

[0101] On the other hand, the present invention also provides a method for detecting a radome using the ultrasonic dry-coupled roller probe, such as Figure 4 、 Figure 5 shown.

[0102] The first element of the ultrasonic dry-coupled roller probe is divided into two equal sections: a delamination defect detection area and a crack defect detection area. The first element is a high-frequency element with dual transmitting and receiving functions. The delamination defect detection area of ​​the first element transmits ultrasonic waves, which propagate longitudinally toward the test object. After reflecting off the bottom surface of the test object, the ultrasonic signal returns along its original path and is received by the first element. The crack defect detection area of ​​the first element transmits ultrasonic waves, which are redirected by the first wedge at the front end of the element and propagate laterally through the test object. After passing through the test object, the ultrasonic signal is redirected along a symmetrical path by the second wedge to return to its original propagation direction and be received by the second element of the probe.

[0103] The center of the ultrasonic sound field is below the center of the delamination defect detection area of ​​the first wafer, and the ultrasonic energy is the highest. When the center of the first wafer coincides with the center of the defect, the energy is blocked to the greatest extent, and no or very little energy is transmitted to the bottom surface of the inspected part. In other words, when the signal strength received by the first wafer is the lowest, it indicates that the delamination defect is located directly below the center of the delamination defect detection area of ​​the first wafer.

[0104] Below the contact boundary line between the first chip and the second chip is the intersection of the sound fields of the two chips, where the ultrasonic energy is the highest. When the center of this position coincides with the center of the crack defect, the energy is blocked to the greatest extent and the ultrasonic signal amplitude is the lowest. Therefore, when the signal intensity received by the second chip is the lowest, it means that the crack defect is located directly below the contact boundary line between the first chip and the second chip.

[0105] The ultrasonic signal amplitude is usually reflected on an ultrasonic instrument. In order to easily distinguish whether the received signal is a delamination defect or a crack defect, in a possible design, the ultrasonic instrument needs to have multiple channels, at least two channels of a penetration mode and a reflection mode.

[0106] Specifically, the delamination defect detection area of ​​the first wafer was connected to the ultrasonic instrument in reflection mode, while the crack defect detection area of ​​the first wafer and the second wafer were also connected to the ultrasonic instrument in penetration mode. To ensure that the frequency range of the low-frequency wafer was within the reception range, the lower limit of the multi-channel ultrasonic instrument's receiving frequency band was no higher than 0.2MHz. To ensure sufficient ultrasonic energy was transmitted, the transmission voltage was no less than 400V square wave.

[0107] In this way, the linkage between the chip, the wedge and the ultrasonic instrument channel is as follows: the first chip has the transmitting and receiving functions, and the crack defect detection area of ​​the first chip is bonded with a triangular wedge; the second chip only has the receiving function, and the front end is also bonded with a triangular wedge, and the two triangular wedges are axially symmetrically distributed. This is to enable the chip in the delamination defect detection area (left half) of the first chip to transmit ultrasonic waves, which propagate longitudinally to the test piece. After the ultrasonic signal is reflected by the bottom surface of the test piece, it returns along the original path and is received by the first chip, and is displayed on the A channel of the ultrasonic instrument; the chip in the crack defect detection area (right half) of the first chip transmits ultrasonic waves, which change direction after the triangular aluminum wedge at the front end of the first chip and propagate horizontally in the test piece. After passing the test piece, the ultrasonic signal returns along a symmetrical path, changes to the original propagation direction after the wedge bonded to the second chip, is received by the second chip, and is displayed on the B channel of the ultrasonic instrument.

[0108] Specifically, the probe detection of defects in the inspected part and the ultrasonic instrument display are linked as follows: when the probe is placed in a defect-free area, the bottom surface ultrasonic reflection signal of channel A and the ultrasonic signal amplitude of channel B are both displayed to be no less than 100%; the center of the chip in the delamination defect detection area (left half) of the probe's first chip coincides with the center position of the delamination defect, so that the amplitude of the bottom surface ultrasonic reflection signal of channel A is displayed to be no more than 20%; the contact boundary line between the first chip and the second chip coincides with the center position of the longitudinal crack defect, so that the amplitude of the ultrasonic signal of channel B is displayed to be no more than 20%.

[0109] More specifically, when the above-mentioned detection method is used to perform ultrasonic scanning of the composite material antenna cover, the scanning mode adopts a grid type to ensure scanning efficiency; the scanning direction is consistent with the direction of the probe roller diameter to facilitate rolling advancement; the scanning step is the radius of the second chip to prevent missed detection.

[0110] In order to facilitate the specific implementation of the ultrasonic dry-coupled roller probe and the detection method for the radome of the present invention, the present invention also provides a specific detection device for the composite material radome, including a multi-channel ultrasonic instrument 14 and an ultrasonic dry-coupled roller probe 18; the ultrasonic dry-coupled roller probe chip includes a first chip 5, a second chip 6, a first wedge 7, and a second wedge 8; Figure 1 、 Figure 2 shown.

[0111] The first wedge 7 is glued to the front end of the crack defect detection area (right half) of the first chip 5, and the second wedge 8 is glued to the front end of the second chip 6. The cross-section of the two wedges is a right triangle, one of the right-angled sides is glued to the chip, the hypotenuses are opposite, and the two wedges are axially symmetrically distributed.

[0112] Specifically, the first chip and the second chip use piezoelectric chips of different frequencies. The first chip uses a high-frequency chip to ensure high resolution when detecting delamination defects; the second chip uses a low-frequency chip to ensure high sensitivity when detecting crack defects.

[0113] The side length of the second wafer is half that of the first wafer. There is no wedge at the front end (left half) of the delamination defect detection area of ​​the first wafer. When ultrasonic waves are transmitted into the test piece, they are reflected back along the original path when encountering a transverse delamination defect and are received by the wafer, thereby determining the location of the transverse delamination defect. A first wedge is bonded to the front end of the crack defect detection area (right half) of the first wafer. When ultrasonic waves are transmitted, they change direction after passing through the first wedge and propagate horizontally into the test piece. When encountering a longitudinal crack defect, they return along a symmetrical path, pass through the second wedge, and change back to their original propagation direction again, which is received by the second wafer, thereby determining the location of the longitudinal crack defect in the test piece.

[0114] In order to ensure that the above-mentioned ultrasonic path is accurately transmitted and received, specifically, the triangular wedge is a wedge with a right-angled triangle cross-section, the thickness of the wedge is consistent with the thickness of the chip, one right-angled side of the triangular wedge is bonded to the chip, and the angle α between the hypotenuse of the wedge and the wedge mounting surface of the corresponding chip (the angle at which the hypotenuse of the wedge and the chip form an acute angle) is in the range of 35° to 55°. When the material of the wedge is preferably metal aluminum, the angle α between the triangular wedge and the chip is preferably 40°. At this time, it can ensure that the ultrasonic wave follows a symmetrical path and is received by the center position of the second chip.

[0115] More specifically, the first chip of the dry-coupled ultrasonic probe, the first chip 5 is a high-resolution, high-energy composite material chip, which has the function of transmitting and receiving ultrasonic signals, a pulse width ≤ 2 cycles, a size range of 15mm*15mm~20mm*20mm, and a center frequency range of 1MHz~5MHz; the second chip 6 is a receiving chip, which only has the function of receiving ultrasonic signals, has a side length of half the side length of the first chip, and a center frequency range of 0.25MHz~1MHz.

[0116] The multi-channel ultrasound device has at least two channels for penetration 15 and reflection 16 working modes.

[0117] Specifically, the lower limit of the receiving frequency band of the multi-channel ultrasonic instrument is not higher than 0.2 MHz, and the transmitting voltage is not lower than square wave 400 V. The two halves of the first wafer are connected to the reflection mode of the ultrasonic instrument via a wire, and the second wafer is connected to the penetration mode of the ultrasonic instrument via a wire.

[0118] In this way, the linkage between the chip, the wedge and the ultrasonic instrument channel is as follows: the first chip has the transmitting and receiving functions, and the delamination defect detection area (left half) of the first chip emits ultrasonic waves, which propagate longitudinally to the test piece. After the ultrasonic signal is reflected by the bottom surface of the test piece, it returns along the original path and is received by the first chip, and is displayed on the A channel of the ultrasonic instrument; the crack defect detection area (right half) of the first chip emits ultrasonic waves, which are changed in direction by the triangular aluminum wedge at the front end of the first chip and propagate horizontally in the test piece. After passing the test piece, the ultrasonic signal returns along a symmetrical path, is changed to the original propagation direction by the wedge at the front end of the second chip, is received by the second chip, and is displayed on the B channel of the ultrasonic instrument.

[0119] The dry-coupled roller probe's probe element is externally sealed with an elastic medium 13 filled with ultrasonic couplant. The elastic medium maintains a consistent thickness. During testing, the probe's elastic medium is pressed tightly against the sample surface, ensuring seamless contact. For example, the elastic medium is a rubber tire, maintaining a consistent thickness.

[0120] To ensure that the probe is pressed tightly against the surface of the test piece, an elastic device is installed between the upper end of the probe and the handle 3 to ensure coupling pressure, and the maximum pressure of the elastic device is ≥ 25 N. For example, the elastic device is a spring.

[0121] The dry-coupled roller probe described above achieves rolling through an axial connection, for example, a bearing, where the roller elastic medium and the surface of the inspected object are scanned through close rolling friction, thereby ensuring dry coupling of the ultrasonic signal.

[0122] The dry-coupled roller probe uses a bearing 11 to roll a rubber tire 13. Close rolling friction between the tire and the surface of the test piece creates a scan. The wafer and the axis 12 holding the wafer remain stationary and positioned closest to the test piece. This means the wafer is perpendicular to the surface of the test piece along the wedge, ensuring that the sound waves enter the test piece vertically. A mechanical seal 10 is placed between the bearing 11 and the wheel 9 to prevent leakage and contamination of the test piece by the liquid couplant.

[0123] The liquid coupling agent between the wafer and the elastic medium is preferably water. The thickness of the water layer is such that the secondary ultrasonic reflection signal of the water is behind the ultrasonic reflection signal of the bottom surface of the test piece and does not affect the detection signal. The ratio of the thickness of the water layer to the longitudinal wave speed in the water should be greater than the ratio of the thickness of the test piece to the longitudinal wave speed in the test piece. Specifically, the thickness of the coupling agent layer (water layer) on the test piece side of the first wafer delamination defect detection area of ​​the dry-coupled ultrasonic probe satisfies the formula:

[0124]

[0125] Among them, L 水层 -Thickness of the water layer, C 水- Longitudinal wave speed in water, T 被检件 -Thickness of the test piece, C 被检件 -The speed of sound of longitudinal waves in the test piece.

[0126] During use, the probe's A port 2 is connected to the A channel transmitter 16 of a multi-channel ultrasound instrument via cable 17, and the probe's B port 1 is connected to the B channel receiver 15 via cable 17. The ultrasound instrument is set to synchronize channels A and B, and testing begins. A grid-like scanning method is used, with the scanning direction aligned with the probe's roller diameter and the scanning step being half the length of the probe's second element (i.e., the radius), ensuring no missed detections and high detection efficiency.

[0127] The present invention provides an ultrasonic detection device for a composite material radome. The detection steps using the above detection device are as follows:

[0128] Step 1: Ensure that the material and thickness of the reference test block are identical to those of the test piece. Place two layers of polytetrafluoroethylene film inside the reference test block to simulate delamination defects, and cut grooves on the lower surface of the reference test block to simulate longitudinal crack defects.

[0129] Step 2: Set the A channel of the multi-channel ultrasound to the reflection method mode and the B channel to the penetration method mode. Connect the A interface of the probe to the A channel transmitter of the multi-channel ultrasound instrument, connect the B interface of the probe to the B channel receiver, and set the ultrasound instrument to synchronize the A channel and the B channel.

[0130] Step 3: Adjust the gain values ​​of channel A and channel B to meet the following requirements: the probe is placed in a defect-free area, the amplitudes of the bottom ultrasonic reflection signal of channel A and the ultrasonic signal of channel B are not less than 100%; the center of the left half of the first chip of the probe coincides with the center position of the artificially simulated delamination defect, so that the amplitude of the bottom ultrasonic reflection signal of channel A is not greater than 20%; the boundary line between the first chip and the second chip coincides with the center position of the artificially simulated longitudinal crack defect, so that the amplitude of the ultrasonic signal of channel B is not greater than 20%.

[0131] Step 4: Use the ultrasonic instrument and probe with determined detection sensitivity to scan the test piece. The scanning method adopts a grid type. The scanning direction is consistent with the direction of the probe roller diameter. The scanning step is the radius of the second wafer of the probe.

[0132] Step 5: During scanning, when the amplitude of the ultrasonic signal of channel A is no more than 20% and is at its lowest, the location of the delamination defect is below the center of the left half of the first wafer. When the amplitude of the ultrasonic signal of channel B is no more than 20% and is at its lowest, the location of the longitudinal crack is below the boundary line between the first wafer and the second wafer.

[0133] Compared to existing technologies, the present invention's parallel placement of the first and second wafers on the same side, along with the triangular wedge, enables single-pass, single-side, single-probe ultrasonic testing of composite radome delamination and crack defects for the first time. Specifically, the triangular wedge is positioned at the front end of the crack detection area on the first wafer. The transmitted ultrasonic wave, passing through the wedge, changes its propagation direction, propagating horizontally through the test piece, thereby detecting longitudinal crack defects.

[0134] Specifically, the detection methods include:

[0135] Step 1: Ensure that the material and thickness of the reference test block are identical to those of the test piece. Place two layers of polytetrafluoroethylene film inside the reference test block to simulate a delamination defect. For example, the delamination defect size ranges from 4mm*4mm to 25mm*25mm. Slot a groove on the bottom surface of the reference test block to simulate a longitudinal crack defect. For example, the groove depth is half the thickness of the reference test block, the groove width ranges from 0.5mm to 1mm, and the groove length ranges from 4mm to 25mm.

[0136] Step 2: Set the A channel of the multi-channel ultrasound to the reflection method mode and the B channel to the penetration method mode. Connect the A interface of the probe to the A channel transmitter of the multi-channel ultrasound instrument, connect the B interface of the probe to the B channel receiver, and set the ultrasound instrument to synchronize the A channel and the B channel.

[0137] Step 3: Adjust the gain values ​​of channel A and channel B to meet the following requirements: the probe is placed in a defect-free area, the amplitudes of the bottom ultrasonic reflection signal of channel A and the ultrasonic signal of channel B are not less than 100%; the center of the left half of the first chip of the probe coincides with the center position of the artificially simulated delamination defect, so that the amplitude of the bottom ultrasonic reflection signal of channel A is not greater than 20%; the boundary line between the first chip and the second chip coincides with the center position of the artificially simulated longitudinal crack defect, so that the amplitude of the ultrasonic signal of channel B is not greater than 20%.

[0138] Step 4: Use the ultrasonic instrument and probe with determined detection sensitivity to scan the test piece. The scanning method adopts a grid type. The scanning direction is consistent with the direction of the probe roller diameter. The scanning step is the radius of the second wafer of the probe.

[0139] Step 5: During scanning, when the amplitude of the ultrasonic signal of channel A is no more than 20% and is at its lowest, the location of the delamination defect is below the center of the left half of the first wafer. When the amplitude of the ultrasonic signal of channel B is no more than 20% and is at its lowest, the location of the longitudinal crack is below the boundary line between the first wafer and the second wafer.

[0140] Compared with the existing technology, the ultrasonic detection method of the present invention realizes the single-shot, single-side, single-probe ultrasonic detection of delamination and crack defects of composite antenna covers for the first time by transmitting and receiving the ultrasonic signals of delamination defects along the same path by the same chip, and transmitting and receiving the ultrasonic signals of crack defects along a symmetrical path by different chips. The two chips are arranged in parallel with the ends adjacent to each other.

[0141] The present invention changes the propagation direction of ultrasonic signals by using triangular wedges, converting longitudinal waves into transverse waves for detecting longitudinal crack defects. Compared with the existing technology, it is the first time that ultrasonic detection of longitudinal cracks is realized.

[0142] Compared with the prior art, the present invention uses two chips with different center frequencies. The high-frequency chip can ensure high resolution when detecting delamination defects, and the low-frequency chip can ensure high sensitivity when detecting crack defects.

[0143] Compared with the prior art, the present invention determines the thickness of the coupling agent to ensure that the multiple ultrasonic reflection waves of the coupling agent are after the reflection waves on the surface of the antenna cover during detection, so that the multiple ultrasonic reflection waves of the coupling agent layer will not affect the ultrasonic reflection signal of the test object, thereby improving the accuracy of detection.

[0144] Compared with the prior art, the present invention ensures the detection sensitivity of delamination and crack defects by verifying the sensitivity of the ultrasonic instrument, thereby further improving the accuracy of the detection results.

[0145] Example 1

[0146] This embodiment provides an ultrasonic dry-coupled roller probe and detection method, and a specific device designed using the above probe and detection method, such as Figure 1 、 Figure 2 The specific details are as follows:

[0147] The first chip 5 of the ultrasonic dry-coupled roller probe is a high-resolution, high-energy composite material chip with transmitting and receiving functions. It has a model number of 1-3, a pulse width of 1.5 cycles, a chip size of 15mm*15mm, and a chip center frequency range of 2.25MHz. The second chip 6 is a receiving chip with only a receiving function. It has a model number of PZT-5, a chip size of 7.5mm*7.5mm, and a center frequency range of 1MHz.

[0148] The high-frequency first chip can ensure high resolution when detecting delamination defects, and the low-frequency second chip can ensure high sensitivity when detecting crack defects.

[0149] The thickness of the coupling agent water layer at the front end of the first element of the dry-coupled roller ultrasonic probe is 10 mm, which satisfies the formula:

[0150]

[0151] Among them, L 水层 -Thickness of the water layer, C 水 - Speed ​​of sound in water, T 被检件 -Thickness of the test piece, C 被检件 -Sound velocity of the test piece.

[0152] like Figure 1 As shown, the ultrasonic dry-coupled roller probe 18 is bonded to the first wedge 7 at the front end of the crack defect detection area (right half) of the first chip 5, and the second wedge 8 is bonded to the front end of the second chip 6. They are axially symmetrical with the first wedge 7, and the symmetry axis is the boundary line between the first chip and the second chip of the probe. The cross-section of the two wedges is a right triangle, one of the right-angled sides is bonded to the chip, and the hypotenuses of the two wedges are opposite. The acute angle formed by the wedge and the chip is 40°, which ensures that the ultrasonic signal can be obliquely incident on the test piece and propagate horizontally in the test piece for detecting longitudinal cracks.

[0153] Fill the rubber tire 13 of the ultrasonic dry-coupled roller probe 18 with couplant water and remove any air bubbles. The wafer and the wafer-fixing shaft 12 remain stationary in the axial direction, and the wafer is perpendicular to the surface of the test piece along the wedge. Ensure that the wafer and wedge ensure that the sealing ring 10 is tightly connected to the wheel disc 9 and bearing 11 to prevent water leaks.

[0154] The transmitting voltage of the A channel and the B channel of the multi-channel ultrasound device 1 is set to 400V (square wave), the A channel and the B channel are synchronized, the receiving frequency band is set to wide band, and the lower limit of the receiving frequency band is ≤0.2MHz.

[0155] The multi-channel ultrasonic instrument 19 is a multi-channel ultrasonic detector having at least two channels of penetration and reflection working modes. Channel A of the multi-channel ultrasonic instrument 19 is set to reflection mode, and channel B is set to penetration mode.

[0156] Connect the A interface 2 of the ultrasonic dry-coupled roller probe 18 to the transmitting end 16 of the A channel of the multi-channel ultrasonic instrument 19, and connect the B interface 1 of the ultrasonic dry-coupled roller probe 18 to the receiving end 15 of the B channel of the multi-channel ultrasonic instrument 19.

[0157] This device can detect delamination defects and / or crack defects. During delamination defect detection, the delamination defect detection area of ​​the first wafer emits ultrasonic waves, which propagate longitudinally to the test piece. After being reflected by the bottom surface of the test piece, the ultrasonic signal returns along the original path and is received by the first wafer. If the ultrasonic signal response is abnormal, it is judged that a transverse delamination defect exists inside the test piece at that location.

[0158] During crack defect detection, the crack defect detection area of ​​the first chip emits ultrasonic waves, which change the propagation direction after being changed by the first wedge and become transverse waves when entering the test piece. After passing through the test piece, the waves follow a symmetrical path and then pass through the second wedge, returning to their original propagation direction and being received by the second chip. If there is an abnormal ultrasonic signal at this time, it indicates that there is a longitudinal crack defect at this position inside the test piece.

[0159] Example 2

[0160] This embodiment provides an ultrasonic dry-coupled roller probe and detection method. The ultrasonic detection device provided in Example 1 is used for detection. The inspected part is an 8 mm thick high-silica fiber reinforced phenolic resin-based composite antenna cover.

[0161] The specific steps are as follows:

[0162] Step 1: Comparison Block Processing: The comparison block is made of the same material as the test piece, with a thickness of 8mm. Two layers of polytetrafluoroethylene film are placed inside the comparison block to simulate a delamination defect, 4mm deep from the top surface, and with a size of 4mm x 4mm. A groove is cut on the bottom surface of the comparison block to simulate a longitudinal crack defect, with a depth of 4mm, a gap width of 0.5mm, and a length of 4mm.

[0163] Step 2: Probe connection and settings: Set the A channel of the multi-channel ultrasound instrument to reflection mode and the B channel to penetration mode. Connect the A interface of the probe to the A channel transmitter of the multi-channel ultrasound instrument, connect the B interface of the probe to the B channel receiver, and set the ultrasound instrument to synchronize the A and B channels.

[0164] Step 3: Determination of detection sensitivity: Press the probe tightly to the surface of the comparison test block, and ensure the coupling pressure by the spring 9 at the upper end of the probe, the pressure is 25N, so that the rubber tire and the test piece are in seamless contact, adjust the gain values ​​of channel A and channel B, and at the same time meet the following requirements: the probe is placed in a place without artificial defects, and the ultrasonic signal amplitudes of channel A and channel B are not less than 100%; the center of the left half of the first chip coincides with the center position of the artificially simulated delamination defect, so that the amplitude of the ultrasonic reflection signal of the bottom surface of the test block of channel A is not greater than 20%; the boundary line between the first chip and the second chip of the probe coincides with the center position of the artificially simulated longitudinal crack defect, so that the amplitude of the ultrasonic signal of channel B is not greater than 20%.

[0165] Step 3: Scanning: Scan the test piece with the determined detection sensitivity. The coupling pressure is the same as that when testing the test block. Scan with a grid scanning method. The scanning direction is consistent with the direction of the probe roller diameter. The scanning step is half the diameter of the second wafer of the probe.

[0166] Step 4: Determination of defect location: During scanning, when the amplitude of the bottom surface ultrasonic reflection signal of channel A is no more than 20% and is at its lowest, the location of the delamination defect is below the center position of the left half of the first wafer. When the amplitude of the ultrasonic signal of channel B is no more than 20% and is at its lowest, the location of the longitudinal crack is below the center of the line connecting the centers of wafers A and B.

[0167] The dissection analysis of the inspected piece of Example 2 shows that the error between the actual defect position and the detected position is within 10%; delamination defects with an actual defect size of 4mm×4mm and above and crack defects with a length of 4mm and above can be quickly detected.

[0168] Example 3

[0169] This embodiment provides an ultrasonic dry-coupled roller probe and detection method. Using the ultrasonic detection device provided in Example 1 and the detection steps provided in Example 2, actual detection is performed on multiple batches of high-silica fiber-reinforced phenolic resin-based composite antenna covers.

[0170] The results of Example 3 demonstrate that the ultrasonic probe and detection method of the present invention can quickly detect delamination defects of 4mm x 4mm or larger and crack defects of 4mm or longer in the radome. Dissection and analysis of the inspected parts show that the error between the actual defect location and the detected location is within 10%.

[0171] Therefore, the ultrasonic probe and detection method of the present invention have a detection lower limit of 4 mm.

[0172] Comparative Example

[0173] In the prior art, a water-jet coupled ultrasonic C-scan detection method is used, which involves spraying water onto the surface of the radome as a coupling agent and scanning for defects inside the radome with an ultrasonic probe.

[0174] The device of this method is complex and large in size. The chip design only has transmitting and receiving functions. It can detect transverse delamination defects but cannot detect longitudinal cracks and determine their locations.

[0175] The results show that the water-jet coupled ultrasonic C-scan detection method in the comparative example has a detection error rate of more than 30% due to water entering the pores of the antenna cover and interfering with the ultrasonic wave. The detection lower limit is 10 mm, and defects below 10 mm cannot be detected.

[0176] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. An ultrasonic dry-coupled roller probe, characterized in that: The invention comprises a first wafer and a second wafer which are parallel to each other and arranged adjacent to each other at their ends; The first wafer is provided with a delamination defect detection area and a crack defect detection area; A first wedge is provided on the crack defect detection area of ​​the first wafer close to the inspected object, and a second wedge is provided on the second wafer close to the inspected object; The ultrasonic signal of the delamination defect detection area of ​​the first wafer is used to detect delamination defects of the inspected object, and the ultrasonic signals of the crack defect detection area of ​​the first wafer and the second wafer are used to detect crack defects of the inspected object; the center frequency of the first wafer is greater than the center frequency of the second wafer; The first wedge and the second wedge are axially symmetrically distributed, with the axis of symmetry being the dividing line between the first wafer and the second wafer. The cross-sections of the first wedge and the second wedge are both right triangles, with the first right-angled sides of the first wedge and the second wedge connected to the wedge mounting surfaces of the corresponding wafers. The second right-angled sides of the first wedge and the second wedge are perpendicular to the wedge mounting surfaces of the corresponding wafers. The hypotenuses of the two right triangles form a Λ shape. The first wedge and the second wedge both satisfy the following formula: Formula 1 Formula 2 Formula 3 Among them, C 楔块材质 is the speed of longitudinal waves in the wedge; C 耦合剂 is the longitudinal wave velocity in the couplant; C 兰姆波 is the Lamb wave speed in the test piece, where the Lamb wave is a transversely propagating sound wave; θ is the angle between the propagation direction of the ultrasonic signal after it changes direction and the original propagation direction; α is the angle between the hypotenuse of the wedge and the wedge mounting surface of the corresponding wafer; β is the difference between the propagation direction of the ultrasonic signal after it changes direction and the vertical line of the hypotenuse of the wedge. Angle.

2. The ultrasonic dry-coupled roller probe according to claim 1, characterized in that: The length ratio of the first wafer to the second wafer is 2:1; The ratio of the length of the delamination defect detection area and the crack defect detection area of ​​the first wafer to the length of the second wafer is 1:1:

1.

3. The ultrasonic dry-coupled roller probe according to claim 1, characterized in that: The probe further includes a cylinder with closed ends and a cylinder rolling connection structure, the first wafer and the second wafer are arranged in the cylinder, and the cylinder is filled with coupling agent; When the cylinder rolls, the first wafer and the second wafer remain stationary relative to the axial direction of the cylinder, and the cylinder and the surface of the inspected object are scanned through close rolling friction.

4. The ultrasonic dry-coupled roller probe according to claim 3, characterized in that: The thickness of the coupling agent layer on the DUT side of the delamination defect detection area of ​​the first wafer should meet the following requirements: Among them, L 耦合剂 -Thickness of the coupling agent layer, C 耦合剂 - longitudinal wave velocity in the couplant, T 被检件 -Thickness of the test piece, C 被检件 -Longitudinal wave velocity in the test piece.

5. An ultrasonic dry-coupling detection method for a radome, characterized in that: The ultrasonic dry-coupled roller probe according to any one of claims 1 to 4 is characterized in that it includes delamination defect detection and / or crack defect detection; The delamination defect detection comprises: emitting ultrasonic waves from the delamination defect detection area of ​​the first wafer, the ultrasonic waves propagating longitudinally to the inspected object, the ultrasonic signals being reflected by the bottom surface of the inspected object and returning along the original path to be received by the first wafer; if the ultrasonic signals are abnormal, it is determined that a transverse delamination defect exists within the inspected object; The crack defect detection includes: the crack defect detection area of ​​the first chip emits ultrasonic waves, which are changed in propagation direction by the first wedge block and become transverse waves when entering the test piece. After passing through the test piece, the waves follow a symmetrical path and then pass through the second wedge block, changing to the original propagation direction and being received by the second chip. If there is an abnormal ultrasonic signal, it is determined that a longitudinal crack defect exists inside the test piece.

6. The detection method according to claim 5, characterized in that the steps include: Step 1: Set artificial simulated defects inside the reference test block, and the material and thickness of the reference test block are the same as those of the test piece; Step 2: Set the ultrasound instrument's channel A to reflection mode and channel B to penetration mode, and synchronize them. Connect the ultrasonic dry-coupled roller probe port to the ultrasound instrument. Step 3: Adjust the gain values ​​of channels A and B. When the ultrasonic dry-coupled roller probe is placed at a non-defective area, the ultrasonic signal amplitude is no less than 100%. When the ultrasonic dry-coupled roller probe is placed at the center of an artificially simulated defect, the amplitude of the ultrasonic reflection signal is no more than 20%. Step 4: Scan the inspected part in a grid-type scanning mode. The scanning direction is consistent with the direction of the probe roller diameter, and the scanning step is half of the second element of the ultrasonic dry-coupled roller probe. Step 5: During scanning, when the amplitude of the ultrasonic signal of channel A is no more than 20% and is at its lowest, the location of the delamination defect is below the center of the delamination defect area of ​​the first wafer. When the amplitude of the ultrasonic signal of channel B is no more than 20% and is at its lowest, the location of the longitudinal crack is below the boundary line between the first wafer and the second wafer.

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