A columnar full-angle ultrasonic probe

Abstract

The application relates to the technical field of ultrasonic detection, in particular to a columnar full-angle ultrasonic probe which comprises a protective film, a matching layer, a planar piezoelectric wafer, a damping block and a supporting rod, wherein the protective film is wrapped on the outer wall of the matching layer; the planar piezoelectric wafer is a rectangular frame structure and is embedded in the inside of the matching layer as a whole; the damping block is arranged in the inside of the rectangular frame of the planar piezoelectric wafer and is provided with a through hole in the middle; and the supporting rod is fixedly arranged in the through hole of the damping block. The application can work under high-frequency conditions, the piezoelectric wafer used is rectangular, the preparation difficulty is low and the piezoelectric wafer is not easy to be damaged under high-frequency conditions, the loss of high-frequency sound waves is smaller when the high-frequency sound waves propagate in a medium, the effective detection depth is deeper and the efficiency is higher when the application is applied to the field of flaw detection, the full-angle detection can be carried out without rotating the hollow shaft type object to be detected, the contact wear between the outer surface of the probe and the surface of the object to be detected is small, and the operation is simple.

Description

Technical Field

[0001] This application relates to the field of ultrasonic detection technology, and more specifically, to a cylindrical omnidirectional ultrasonic probe. Background Technology

[0002] Ultrasonic testing utilizes the property that ultrasonic waves generated by piezoelectric crystals are reflected or refracted on materials of different media, interfaces, or densities to determine internal defects in workpieces. It has wide applications in steel corrosion and welded seams of building steel structures.

[0003] Ultrasonic waves have been widely used in detection activities, and have also seen multifaceted development in the field of ultrasonic flaw detection. According to literature, early ultrasonic flaw detection research mainly focused on theoretical and laboratory levels. In 1921, Canadian physicist Foster conducted experiments on the propagation of ultrasonic waves. In the following decades, researchers gradually understood the propagation characteristics of ultrasonic waves in different media and how to utilize these characteristics to detect defects. With the development of modern electronic technology, ultrasonic flaw detector technology is now very mature, and instruments suitable for different scenarios have emerged.

[0004] Hollow shafts are widely used in transportation vehicles such as vehicles and trains, as well as various mechanical devices. Therefore, it is crucial to inspect and test these structures, which play a vital role in mechanical engineering, to ensure their quality meets operational requirements and prevent potential safety hazards. Existing detection technologies all have limitations when testing these structures. Retractable probes cannot fit snugly against curved surfaces, resulting in significant wear during operation. Cylindrical probes use crystals that cannot withstand high-frequency currents, making them prone to breakage under high-frequency conditions. Phased array detection requires advanced manufacturing processes and is technically challenging. Summary of the Invention

[0005] This application provides a cylindrical full-angle ultrasonic probe that utilizes the different refractive indices of sound waves in different media to convert plane waves generated by piezoelectric crystals into cylindrical waves, thereby reducing the number of detections and improving detection efficiency.

[0006] To achieve the above objectives, this application provides a cylindrical omnidirectional ultrasonic probe, comprising a protective film, a matching layer, a planar piezoelectric crystal, a damping block, and a support rod, wherein: the protective film is wrapped around the outer wall of the matching layer; the planar piezoelectric crystal has a rectangular frame structure and is embedded entirely inside the matching layer; the damping block is disposed inside the rectangular frame of the planar piezoelectric crystal and has a through hole in the middle; and the support rod is fixedly disposed inside the through hole of the damping block.

[0007] Furthermore, the matching layer includes a first matching layer and a second matching layer, with the first matching layer disposed between the second matching layer and the protective film, and the sound velocity of the material in the first matching layer being lower than the sound velocity of the material in the second matching layer.

[0008] Furthermore, the shape of the second matching layer is determined by the materials of the first and second matching layers.

[0009] Furthermore, the planar piezoelectric wafer is a rectangular frame structure composed of four rectangular piezoelectric wafers, each of which is bonded to the inside of the second matching layer.

[0010] Furthermore, the protective film is made of polyurethane soft plastic.

[0011] Furthermore, the damping block is made of a mixture of tungsten powder and epoxy resin, and is bonded to the inside of the rectangular frame of the planar piezoelectric wafer.

[0012] Furthermore, the support rod is a hollow cylinder, with one end fixed inside the through hole of the damping block and the other end connected to a BNC wire.

[0013] Furthermore, it can achieve 360° omnidirectional coverage at frequencies of 1-2.5MHz.

[0014] The cylindrical full-angle ultrasonic probe provided in this application has the following beneficial effects:

[0015] This application can operate under high-frequency conditions. The piezoelectric crystal used is rectangular, which is easy to manufacture and not easily damaged under high-frequency conditions. The loss of high-frequency sound waves when propagating in the medium is smaller. When applied to the field of flaw detection, it can effectively detect deeper and more efficiently. Furthermore, it can perform full-angle detection without rotating hollow shaft-type test objects. The contact wear between the outer surface of the probe and the surface of the test object is small, and the operation is simple. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings:

[0017] Figure 1 This is a schematic diagram of a cylindrical full-angle ultrasonic probe provided according to an embodiment of this application;

[0018] Figure 2 This is a cross-sectional schematic diagram of a cylindrical full-angle ultrasonic probe provided according to an embodiment of this application;

[0019] Figure 3 yes Figure 2 A 1 / 8 diagram illustrating the generation of a cylindrical wavefront;

[0020] In the figure: 1-protective film, 2-first matching layer, 3-second matching layer, 4-planar piezoelectric wafer, 5-damping block, 6-support rod. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0024] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0025] In addition, the term "multiple" should mean two or more.

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] like Figure 1 As shown, this application provides a cylindrical omnidirectional ultrasonic probe, including a protective film 1, a matching layer, a planar piezoelectric crystal 4, a damping block 5, and a support rod 6, wherein: the protective film 1 is wrapped around the outer wall of the matching layer; the planar piezoelectric crystal 4 has a rectangular frame structure and is embedded in the interior of the matching layer; the damping block 5 is disposed inside the rectangular frame of the planar piezoelectric crystal 4, and a through hole is provided in the middle; the support rod 6 is fixedly disposed inside the through hole of the damping block 5.

[0028] Specifically, the cylindrical omnidirectional ultrasonic probe provided in this application embodiment is mainly for achieving omnidirectional detection under high-frequency conditions. By bonding multiple piezoelectric wafers, a better radial distribution of the sound beam is achieved before it enters the matching layer. The sound velocity ratio can be changed according to the material of the matching layer, thereby obtaining an interface shape with better detection performance. The different refractive indices of different media are used to convert the plane wave generated by the piezoelectric wafer into a cylindrical wave. The planar piezoelectric wafer 4 is easy to manufacture, has low loss during sound wave propagation, high flaw detection efficiency, and significant effect.

[0029] Furthermore, the matching layer includes a first matching layer 2 and a second matching layer 3. The first matching layer 2 is disposed between the second matching layer 3 and the protective film 1, and the sound velocity of the material of the first matching layer 2 is lower than the sound velocity of the material of the second matching layer 3.

[0030] Specifically, by utilizing the different refractive indices of the acoustic waves in the different matching layers, the plane waves generated by the piezoelectric wafer can be converted into cylindrical waves. The materials of the two matching layers are not fixed and are selected according to actual conditions. If both are solid materials, they are fixed by adhesive bonding; if one is a liquid material and the other is a solid material, they are fixed by liquid sealing. In the embodiments of this application, the material of the first matching layer 2 is preferably machine oil, and the material of the second matching layer 3 is preferably acrylic material. The machine oil is sealed between the acrylic material and the protective film 1. The sound velocity of the first matching layer 2 (machine oil) is approximately 1200 m / s at room temperature and pressure, and the sound velocity of the second matching layer 3 (acrylic) is approximately 2400 m / s at room temperature and pressure. The sound velocity of the first matching layer 2 must be less than the sound velocity of the second matching layer 3 to ensure that the planar ultrasonic waves propagate radially along the cylindrical surface after refraction at the interface.

[0031] Furthermore, the shape of the second matching layer 3 is determined by the materials of the first matching layer 2 and the second matching layer 3.

[0032] Specifically, the shape of the matching layer is determined by its material; that is, its shape is calculated based on the sound velocity in the first matching layer 2 and the second matching layer 3. In this embodiment, the material of the first matching layer 2 is engine oil, and the material of the second matching layer 3 is acrylic. Therefore, the calculated shape of the second matching layer 3 is a "cross" shape, such as... Figure 2As shown. The calculation process is as follows: when the planar piezoelectric crystal 4 emits planar ultrasonic waves, refraction will occur at the interface between the two matching layers. During the refraction process, the sound wave satisfies the following law of refraction:

[0033]

[0034] Where c1 and c2 are the sound velocities of the first matching layer 2 and the second matching layer 3, respectively; θ t θ is the emission angle of the first matching layer 2. i The incident angle of the second matching layer 3.

[0035] In order for the emitted sound wave to propagate radially along the cylindrical surface, i.e., its backward extension must pass through the origin of the coordinate system, the propagation speed of the sound wave in the two media must satisfy c2 > c1 according to the law of refraction.

[0036] Figure 3 yes Figure 2 The first quadrant, in Figure 3 In, θ i θ is the angle of incidence; t The angle of refraction; θ = θ i -θ t θ can be represented by the horizontal and vertical coordinates at the interface of the matching layer: Substituting the two geometric relationships above into the law of refraction, we get:

[0037]

[0038] Thus, the differential equation of the matching layer interface is obtained:

[0039]

[0040] Based on the above differential equation, the form of the construction curve can be obtained by solving it using MATLAB software. Then, the shape of the matching layer interface can be obtained by performing mirror symmetry and rotational symmetry operations.

[0041] Furthermore, the planar piezoelectric wafer 4 is a rectangular frame structure composed of four rectangular piezoelectric wafers, each of which is bonded to the interior of the second matching layer 3. The planar piezoelectric wafer 4 consists of four individual rectangular piezoelectric wafers bonded to the interior of the second matching layer 3, forming a rectangular frame structure. A single signal generator provides synchronized ultrasonic waves to the four piezoelectric wafers, reducing detection errors in different directions. Moreover, the manufacturing process of the rectangular piezoelectric wafers is simple, and the overall number of piezoelectric wafers is small, resulting in a relatively simple control system inside the probe.

[0042] Furthermore, the protective film 1 is made of polyurethane soft plastic. The protective film 1, made of polyurethane soft plastic, can better adapt to changes in surface shape and provide good acoustic coupling. During the bonding and wrapping process, the adhesive layer remains relatively thin, preventing air infiltration.

[0043] Furthermore, the damping block 5 is made of a mixture of tungsten powder and epoxy resin, and is bonded to the inside of the rectangular frame of the planar piezoelectric wafer 4. The damping block 5 is tightly attached to the back of the piezoelectric wafer to reduce wafer aftershocks and absorb acoustic energy from the back.

[0044] Furthermore, the support rod 6 is a hollow cylinder, with one end fixed inside the through hole of the damping block 5 and the other end connected to a BNC wire. The support rod 6 is made of steel and serves two purposes: firstly, to fix the planar piezoelectric wafer 4 and the damping block 5; and secondly, as part of the electrode, to connect the electrode leads of the piezoelectric wafer and to the subsequent control and display device. The support rod 6 has a hollow internal structure for leading out the wires.

[0045] Furthermore, it can achieve 360° omnidirectional coverage at frequencies of 1-2.5MHz.

[0046] Specifically, the cylindrical omnidirectional ultrasonic probe provided in this application embodiment can achieve 360° omnidirectional coverage detection at a high frequency of 1-2.5MHz. The working process is as follows: First, a function generator connected to the support rod 6 generates an alternating electrical signal of a specific frequency. When the planar piezoelectric crystal 4 senses a change in voltage, it undergoes periodic deformation at the same frequency as the alternating electrical signal. The periodic deformation of the planar piezoelectric crystal 4 causes environmental vibration and excites sound waves to propagate outward in the form of longitudinal waves. Because the propagation of sound waves is similar to that of light waves and also satisfies Huygens' theorem, ultrasonic waves can be regarded as propagating in a straight line during propagation. Therefore, through the conversion of the planar piezoelectric crystal 4, longitudinal waves propagating in the form of plane waves can be obtained. Subsequently, ultrasonic waves have good geometric effects when propagating in solids. When propagating between two matching layer interfaces, obvious refraction and reflection phenomena occur, thus converting them into cylindrical waves. When the cylindrical waves reach the surface of the object to be tested, they are reflected to form echoes. After receiving the echoes, the planar piezoelectric crystal 4 deforms again. This deformation signal is converted into an electrical signal by the piezoelectric crystal and received and processed by the subsequently connected oscilloscope, thereby determining whether there are defects in the object to be tested and achieving the purpose of flaw detection.

[0047] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A cylindrical omnidirectional ultrasonic probe, characterized in that, It includes a protective film, a matching layer, a planar piezoelectric wafer, a damping block, and a support rod, wherein: The protective film is wrapped around the outer wall of the matching layer; The planar piezoelectric wafer has a rectangular frame structure and is embedded entirely inside the matching layer; The damping block is disposed inside the rectangular frame of the planar piezoelectric wafer, and a through hole is provided in the middle; The support rod is fixedly installed inside the through hole of the damping block; The matching layer includes a first matching layer and a second matching layer. The first matching layer is disposed between the second matching layer and the protective film. The sound velocity of the material in the first matching layer is lower than the sound velocity of the material in the second matching layer. The shape of the second matching layer is determined by the materials of the first matching layer and the second matching layer.

2. The cylindrical full-angle ultrasonic probe according to claim 1, characterized in that, The planar piezoelectric wafer is a rectangular frame structure composed of four rectangular piezoelectric wafers, each of which is bonded to the inside of the second matching layer.

3. The cylindrical full-angle ultrasonic probe according to claim 2, characterized in that, The protective film is made of polyurethane soft plastic.

4. The cylindrical all-angle ultrasonic probe according to claim 3, characterized in that, The damping block is made of a mixture of tungsten powder and epoxy resin and is bonded to the inside of the rectangular frame of the planar piezoelectric wafer.

5. The cylindrical all-angle ultrasonic probe according to claim 4, characterized in that, The support rod is a hollow cylinder, with one end fixed inside the through hole of the damping block and the other end connected to a BNC wire.

6. The cylindrical all-angle ultrasonic probe according to claim 5, characterized in that, It can achieve 360° omnidirectional coverage at frequencies of 1-2.5MHz.

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