An ultrasonic testing transducer clamp for a phased linear array

Abstract

The application discloses a transducer clamp which can be used for ultrasonic detection of an ultrasonic linear phased array, the clamp is connected with a terminal flange plate of a six-degree-of-freedom industrial robot through a positioning flange structure at the top end, and relative staticness of the clamp and the terminal end of the robot is ensured. The overall shape of the bottom bin adopts a Veedosinski curve, water flow can be effectively gathered, and four symmetrically distributed water injection ports are designed at the top of the bottom bin, water flow is increased, and stability of the robot in the movement process is ensured. In order to ensure that the clamp can be used for various ways of phased array detection, the water outlet is designed and can meet the water column required when the phased array is deflected and focused by 30 degrees through calculation. The screen can effectively filter bubbles, buffer water flow, prevent the terminal end of the robot from shaking, and improve the water column quality. The above-mentioned parts work together to realize the water column coupling required by the water spray focusing of the phased array.

Description

Technical Field

[0001] This invention relates to a transducer fixture for a linear phased array that can be used in ultrasonic water jet testing. It belongs to the water coupling auxiliary system of a multifunctional multi-degree-of-freedom ultrasonic phased array testing system and is in the field of ultrasonic phased array nondestructive testing technology for near-surface defects of workpieces. Background Technology

[0002] High-performance metallic materials, such as aluminum and high-temperature aluminum alloys, are widely used in aerospace, automotive, shipbuilding, and marine engineering fields due to their high strength, corrosion resistance, and toughness, as well as their complex curved surface workpieces. Because the machining process for complex curved surface workpieces is intricate and costly, they are widely used in critical load-bearing structures and core components of power systems, such as the upper wing skin of space shuttles, aircraft shells, and engine blades in the aerospace field. Therefore, higher standards and greater demands are expected for the inspection of key aircraft components. Taking turbine engine blades as an example, due to their complex manufacturing process and long-term operation under extreme environments such as alternating loads, high temperatures, and high speeds, defects such as overlapping pore edges and back wall damage are prone to occur during manufacturing. During service, defects such as fatigue cracks, surface coating tears, and pore cracks are likely to occur. If these defects are not detected and addressed in a timely manner, they will lead to crack propagation and even the fracture of the entire structure, seriously affecting the service life of the blades and the flight safety of the aircraft.

[0003] Ultrasonic non-destructive testing (UNDT), as an important testing method in non-destructive testing, is widely used in various fields due to its advantages such as low testing cost, wide range of test objects, high sensitivity, and harmlessness to the human body. Ultrasonic phased array testing is a multi-channel scanning imaging technology that can flexibly control the sound beam emission state according to the time delay law. A phased array probe is an array transducer composed of multiple independent piezoelectric crystals arranged according to a certain rule, where each piezoelectric crystal is also called an array element, and each array element should have an excitation / receiving circuit. The most significant advantage of ultrasonic phased array technology is that it flexibly controls the shape of the sound beam and the sound pressure distribution through electronic technology, achieving linear scanning, sector scanning, dynamic depth focusing scanning, and combinations of various scanning modes with little or no probe movement. This avoids problems such as poor workpiece accessibility and spatial limitations, allowing for multi-angle and multi-directional scanning of the target area, obtaining real-time A-scan, B-scan, C-scan, S-scan, and three-dimensional imaging views. Using ultrasonic phased arrays to detect near-surface defects on planar and curved surfaces offers more flexible detection options, enabling large-scale scanning and promising a wide range of applications.

[0004] There are already many mature series of ultrasonic phased array testing equipment, including the PipeWIZARD pipeline inspection system from R / DTECH in Canada, the Sync Scan series, SUPOR series, and GEKKO series of portable flaw detectors from M2M in France, the Ominiscan SX and MX2 series of portable flaw detectors from OLYMPUS in the United States, and the Phascan series of portable ultrasonic phased array testing instruments from Duopule Electronic Technology Co., Ltd. in China. Currently, phased array equipment is mainly portable and consists of small integrated mechanical structures used for pipeline inspection. Multi-degree-of-freedom testing equipment has only seen some attempts abroad, and sufficient R&D experience has not yet been accumulated. This invention is part of an independently developed multi-degree-of-freedom ultrasonic phased array testing system. The fixture, as a component connecting the mechanical motion submodule and the ultrasonic excitation receiving submodule, plays a crucial role. Therefore, the design of this fixture requires combining the testing method and functionality to develop a corresponding structural design, demonstrating creativity and scientific rigor. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of connecting the six-degree-of-freedom robotic arm motion mechanism with the ultrasonic phased array in an ultrasonic phased array C-scan detection system. The structure of this invention is specially designed to meet the key technical challenges of phased array detection, while minimizing the complexity of disassembly and assembly by integrating the components as much as possible. This invention uses aluminum alloy and rubber as materials and recommends using 3D printing to manufacture the fixture, which offers advantages such as good security, low cost, compatibility with various phased array models, and sufficient rigidity.

[0006] The technical solution adopted in this invention is a multi-degree-of-freedom ultrasonic phased array C-scan detection system based on water spray detection. In addition to the above-mentioned indicators, the invention needs to ensure the effective application of the phased array delay law. The nozzle can be mainly divided into five main structures according to function: flange 1, base chamber 7, rubber chamber 11, probe mounting bracket 14, and bottom cover 18. This invention can be further subdivided into the following structures: robotic arm flange positioning hole 2; flange fixing base 3; flange base positioning hole 4; pagoda-shaped water inlet 5; mounting bracket base 6; rubber chamber handle 8; handle opening 9; probe cable port 10; mounting bracket positioning hole 12; mounting bracket support cover 13; comb-shaped chamber support 15; bottom cover positioning hole 16; and screen 17.

[0007] As shown in the attached diagram of the instruction manual, the overall assembly diagram of this phased array fixture design is as follows: Figure 1 As shown in the diagram, its internal structure is as follows: Figure 2 As shown, Figure 3 and Figure 4The accompanying drawings show the front and top views of the fixture assembly. Additionally, details of important structures are shown in the drawings. The bottom cover 18, which serves as the outlet of the fixture, contains an embedded screen 17. To accurately illustrate its structure, [details omitted]. Figure 5 The front view, top view, and bottom view of the bottom cover 18 are presented in the image. Figure 6 The specific appearance of the rubber chamber 11 and the probe holder 14 is shown. Figure 7 In the design process of the bottom compartment 7 of this project, the Widosinski curve was used, and the equation of the Widosinski curve was edited and calculated using MATLAB software.

[0008] The specific design concepts are as follows:

[0009] 1. The top of flange 1 is equipped with four robotic arm flange positioning holes 2. The distribution of these holes is consistent with the distribution of the positioning holes on the end flange of the SIASUN SR4B industrial robotic arm selected for the system. These holes are mainly used to connect the end flange of the ultrasonic testing robotic arm. The bottom of flange 1 has a "four-leaf clover" shaped flange fixing base 3 for connecting flange 1 to the base chamber 7. The "four-leaf clover" design is due to the relatively small size of the robotic arm flange. Considering the need to fix the phased array transducer inside the fixture's chamber, the top cross-sectional area of ​​the base chamber 7 is relatively large. The flange fixing base 3 is designed with an outward expansion structure to facilitate the installation of flange base positioning holes 4 at the bottom of flange 1, increasing the overall rigidity of the fixture. Flange 1 and the robotic arm end flange must be synchronized during operation, and the normal vector of the center of the robotic arm end flange must coincide with the normal vector of the center of the top opening of flange 1. This ensures that the center of the phased array is perpendicular to the sweep point of the workpiece surface during operation.

[0010] 2. The main body of the bottom chamber 7 plays a decisive role in the convergence of the water flow. Its overall length should not be too short, as this would hinder water column convergence; at the same time, it should not be too long, as this would reduce the flexibility of the robotic arm's end effector. The final overall length of this invention is set at 70mm. The Vidosinski curve has been proven in numerous domestic and international publications to have an auxiliary effect on fluid ejection, and this invention uses this curve for the shape design of the bottom chamber 7. Since the curve is a complex surface with continuous curvature changes, completely adopting this surface may lead to serious processing errors, which could negatively impact the energy of the jet. Therefore, four straight line segments are used for fitting to ensure sufficient jet energy. Additional lines are used at distances of 17.5mm, 35mm, and 52.5mm from the top of the bottom chamber 7. Figure 7 The procedure shown is used to calculate the Dosinski curve, yielding values ​​of 42.9 mm, 38.9 mm, and 35.9 mm, respectively.

[0011] 3. The design of the water inlet 5 in the pagoda takes into account sealing and the impact of water inflow on the vibration of a certain section of the robotic arm. Since a 4-point inner diameter steel wire hose is selected for the water pipe, the maximum diameter of the pagoda should be 20mm, and a sealing effect can be achieved through clamps. Due to the large size of the bottom chamber 7, a single water inlet is insufficient for adequate filling. Adding more water inlets would increase jet collisions. To prevent vibration at the end of the robotic arm, four symmetrically distributed inlets are designed to prevent vibration.

[0012] 4. The design of the transducer mounting base 14 primarily considers the focusing principle of the phased array. Unlike the focusing mechanism of a single-element ultrasonic transducer, the phased array probe does not use lenses but relies on a focusing law. Since this equipment uses a water jet detection method, there is an underwater acoustic distance. This distance consists of the distance inside the fixture and the distance of the water jet. Therefore, to ensure controllable distance inside the fixture, a mounting base is needed to fix the specific position of the phased array transducer. This design ensures that the distance inside the fixture is 7mm.

[0013] 5. The mounting base 14 is fixed in the groove of the bottom compartment 7 by the mounting support cover 13. The fixing method is to fix it with two symmetrically distributed mounting positioning holes 12. The groove of the bottom compartment 7 and the mounting support cover 13 are at the same height, so it will not affect the overall structure after assembly.

[0014] 6. The comb-shaped support 15 adopts a comb-like structure, which has a certain degree of toughness and will not cause plastic deformation and damage to the structure when assembling the rubber chamber 11. The bottom of the support has inward protrusions of 3.5mm and 5.5mm width to support the rubber chamber 11.

[0015] 7. The top of the rubber compartment 11 has a rubber compartment handle 8, with a hole cut in the middle to form a handle opening 9. The design is inspired by the structure of a plastic bag. This structure facilitates the removal of the rubber compartment 11 from the inside of the mounting base 14 during disassembly and assembly. A probe cable port 10 is provided at the top to connect the phased array's transmission lines to the outside. The bottom of the rubber compartment also has an inwardly protruding structure to protect the phased array casing from scratches by the comb-shaped compartment support 15.

[0016] 8. The bottom cover 18 has three bottom cover positioning holes 16 to connect it to the bottom chamber 7. To simplify the structure of the clamp, the screen 17 adopts an integrated design. Its complex design is derived from the drain structure, which can effectively buffer the water flow and prevent repeated impacts on the bottom cover 18 to form air bubbles. At the same time, its filter mesh also has the function of filtering large air bubbles. A rectangular water outlet with a diameter of 36*14mm is set at the bottom of the bottom cover 18 to meet the requirements of linear focusing, deflection focusing, and deflection.

[0017] The assembly method is as follows:

[0018] The flange positioning hole 2 of the robotic arm is connected to the flange of the robotic arm wrist by a standard M5 bolt threaded connection.

[0019] The flange mounting base 3 and the bottom compartment 7 are connected by a standard M5 bolt with threaded engagement.

[0020] Pass the phased array cable through the probe cable port 10, and insert the phased array transducer into the rubber chamber 11 from bottom to top;

[0021] The rubber chamber 11 is inserted downward from the top of the mounting base 14;

[0022] The comb-shaped support 15 holds the rubber chamber 11, and the gaps can be used to observe whether they fit properly.

[0023] The mounting bracket positioning hole 12 on the mounting bracket support cover 13 is engaged with the mounting bracket base 6 by a standard M2.5 bolt;

[0024] The four pagoda-shaped water inlets 5 are connected to four outer water pipes with an inner diameter of 4 points respectively via a straight insertion method and are secured with clamps;

[0025] The bottom cover 18 and the bottom compartment 7 are connected by a standard M3 bolt with a threaded connection.

[0026] The bottom cover 18 and the screen 17 are designed as a single unit.

[0027] The fixture itself is relatively large and subject to water flow impact. Therefore, to reduce the load on the robotic arm's end effector, the fixture needs to be made of a lightweight material; this fixture is made of aluminum alloy. Rubber gaskets are added at the joints to improve sealing. The fixture's screen has two mesh structures: the outermost layer has fine, elongated keyed mesh holes, primarily responsible for collecting large flow rates and finely filtering out air bubbles. The middle section, due to its gentler slope, has coarser keyed mesh holes to mitigate water flow impact while still filtering out air bubbles. The center of the screen, being the central part of the water jet outlet, must be air-free; therefore, it features a denser arrangement of circular holes. Water spray testing showed that the fixture can produce a good jet, meeting the detection conditions under certain underwater acoustic distances. Attached Figure Description

[0028] Figure 1 Overall assembly diagram of the transducer fixture;

[0029] Figure 2 Exploded view of the transducer fixture (with annotations);

[0030] Figure 3 Front view of the transducer fixture;

[0031] Figure 4 Top view of the transducer fixture;

[0032] Figure 5 Three-view drawing of the bottom cover;

[0033] Figure 6 Detailed view of the rubber chamber (left) and probe mounting bracket (right);

[0034] Figure 7 The equation of the Widosinski curve was solved using MATLAB. Detailed Implementation

[0035] The specific implementation method of the transducer fixture will be further explained below.

[0036] A transducer fixture for a linear phased array used in ultrasonic water jet testing comprises a flange 1, a base chamber 7, a rubber chamber 11, a probe holder 14, and a bottom cover 18 as its main components. A robotic arm flange positioning hole 2 is used to connect to the end effector wrist flange of SIASUN's SR4B robotic arm. The probe holder 14 is fixed to the interior of the base chamber 7 via a holder positioning hole 12. The outer surface of the rubber chamber 11 can be coated with industrial grease to ensure easy sliding into the probe holder 14. The system ensures water tightness; the four pagoda-shaped water inlets 5 are directly connected to four outer water pipes with an inner diameter of 4 points, and are secured with clamps; if the phased array transducer needs to be replaced, the rubber chamber can be easily lifted out through the rubber chamber handle 8; the pagoda-shaped water inlets 5 inject water into the bottom chamber 7 through the 4-point gate under the pressure of the industrial water pump; the bottom cover 18 is connected to the lower part of the bottom chamber 7 through the bottom cover positioning hole 16, and is wrapped with PTFE tape to increase sealing; the screen 17 can buffer the water flow and filter air bubbles to ensure the continuity of water output.

[0037] Flange 1 is located below the flange on the wrist of the robotic arm and is connected by standard M5 bolts. The flange mounting base 3 is connected to the bottom chamber 7 via four flange base positioning holes 4, also connected by standard M5 bolts. The bottom cover 18 is located below the bottom chamber 7 and is connected by standard M3 screws. The mounting bracket positioning holes 12 on the mounting bracket support cover 13 are connected to the mounting bracket base 6 via standard M2.5 bolts, completing the connection of the probe mounting bracket 14. The rubber chamber 11 slides into the probe mounting bracket 14. The screen 17 and the bottom cover 18 are integrated. Since both the robotic arm and the multi-channel excitation receiver board generate electromagnetic signals, plastic M5 bolts and M5 plastic washers are used for electromagnetic shielding. The pagoda-shaped water inlet 5 is connected to the external water pipe via a direct insertion method and secured with clamps on the outside of the water pipe.

[0038] Flange 1, base chamber 7, probe holder 14, and bottom cover 18 are manufactured as a single 3D printed component. Base chamber 7 is designed using the Vidosinski curve, with parameters as shown in the design concept. The shortest distance between the screen 17 in the bottom cover 18 and the inner wall of the outlet is 1mm. The outlet has a stretch of 1.5mm, and the thickness of the bottom cover and the thinnest part of the screen are both 0.5mm. Therefore, the distance between the screen and the outlet is strictly controlled to 2mm. The rubber chamber 11 is 1mm thick, the probe holder 14 is 1mm thick, and the bottom of the holder is 5mm from the outlet. Therefore, the distance between the array element and the outlet can be determined to be 7mm.

[0039] The usage method is as follows: First, insert the phased array transducer into the bottom of the rubber sleeve 11, and pass the transducer cable through the probe cable port 10. Apply industrial grease to the outer layer of the rubber sleeve 11, and slide it down from the top of the probe mounting bracket 14 into the comb-shaped compartment support 15, ensuring a good fit. The mounting bracket support cover 13 of the probe mounting bracket 14 has two symmetrically distributed mounting bracket positioning holes 12, which are engaged with the mounting bracket base 6 using standard M2.5 bolts. After the internal installation of the fixture is completed, connect the bottom cover 18 to the bottom compartment 7 using standard M3 bolts, and then bind the outside with PTFE. The installation of the flange 1 is divided into two steps: First, connect the flange positioning hole 2 of the robotic arm to the flange of the robotic arm wrist using standard M5 bolts, and then connect the flange mounting base 3 to the bottom compartment 7 using standard M5 bolts. This order is because the flange 1 is wider at the bottom and narrower at the top, which facilitates installation. Finally, connect the four pagoda-shaped water inlets 5 to the four outer water pipes with an inner diameter of 4 points respectively using a straight-insertion method and tighten them with clamps.

[0040] The transducer fixture designed in this invention has a simple structure, fewer parts, is easy to assemble, has low cost, good sealing performance, and high reliability, and can meet the testing requirements of water-jet ultrasonic phased arrays.

Claims

1. A transducer fixture for a linear phased array that can be used in ultrasonic water jet detection, characterized in that: Includes a flange (1), a bottom chamber (7), a rubber chamber (11), a probe mounting bracket (14), and a bottom cover (18); the robotic arm flange positioning hole (2) is used to connect the robotic arm end wrist flange; the probe mounting bracket (14) is fixed to the inside of the bottom chamber (7) through the mounting bracket positioning hole (12) and the mounting bracket base (6); the outer surface of the rubber chamber (11) is coated with grease; four pagoda water inlets (5) are respectively connected to four external water pipes through a straight insertion method and are secured with clamps; the pagoda water inlets (5) inject water into the bottom chamber (7) through a four-part gate under the pressure of an industrial water pump; the bottom cover (18) is connected to the lower part of the bottom chamber (7) through the bottom cover positioning hole (16) and is wrapped with PTFE tape to increase sealing; an integrated screen (17) is embedded inside the bottom cover (18); the phased array transducer is fixed inside the bottom chamber (7); the bottom of the probe mounting bracket (14) is provided with a comb-shaped chamber support (15). The flange (1) is located below the flange of the wrist at the end of the robotic arm and is connected by bolts; the flange fixing base (3) is connected to the bottom chamber (7) by four flange base positioning holes (4) through threaded connection; the bottom cover (18) is located below the bottom chamber (7); the fixing bracket positioning hole (12) on the fixing bracket support cover (13) is connected to the fixing bracket base (6) by bolts to complete the connection of the probe fixing bracket (14); the rubber chamber (11) is engaged with the probe fixing bracket (14) by sliding. The comb-shaped support (15) adopts a comb tooth structure; the inward protrusion structure at the bottom of the support is used to hold the rubber tank (11). The top of the rubber chamber (11) has a rubber chamber handle (8), with a hole in the middle of the handle forming a handle opening (9); the upper part of the rubber chamber (11) has a probe cable port (10) to connect the transmission line of the phased array transducer to the outside; the bottom of the rubber chamber also has an inward protruding structure to protect the phased array shell from being scratched by the comb-shaped chamber support (15).

2. The transducer fixture for a linear phased array used in ultrasonic water jet detection as described in claim 1, characterized in that: The flange (1) serves as the connecting component between the end flange of the robotic arm and the base (7). It uses a flange fixing base (3) that is "thin at the top and thick at the bottom" and has a "four-leaf clover" shape. The flange fixing base (3) is made into an outwardly expanding structure. The bottom of the flange (1) is provided with a flange base positioning hole (4).

3. The transducer fixture for a linear phased array used in ultrasonic water jet detection as described in claim 1, characterized in that: When replacing the phased array transducer, lift the rubber chamber out through the rubber chamber handle (8).

4. The transducer fixture for a linear phased array used in ultrasonic water jet detection as described in claim 1, characterized in that: The base (6) of the fixed frame is fixed in the groove of the bottom compartment (7) by the fixed frame support cover (13) and fixed by two symmetrically distributed fixed frame positioning holes (12); the groove of the bottom compartment (7) is at the same height as the fixed frame support cover (13).

5. The transducer fixture for a linear phased array used in ultrasonic water jet detection as described in claim 1, characterized in that: The bottom cover (18) has three bottom cover positioning holes (16) to connect it to the bottom compartment (7).

6. The transducer fixture for a linear phased array used in ultrasonic water jet detection as described in claim 1, characterized in that: The phased array transducer has the feature of array arrangement. The linear phased array is arranged in a rectangle, so that the sound beam can be fully incident on the surface of the workpiece. A rectangular water outlet is set at the bottom of the bottom cover (18).

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