A riveting product fatigue test installation loading auxiliary tool and method

Abstract

The application belongs to the field of test and measurement, and relates to an auxiliary tool and method for riveting product fatigue test installation and loading. The auxiliary tool comprises a loading joint assembly, a loading connection assembly, a riveting transition assembly and a connecting seat. The loading joint assembly is connected to the riveting product through the loading connection assembly, the riveting product is installed on the connecting seat through the riveting transition assembly, and the axial center of the loading joint assembly and the axial center of the loading connection assembly are perpendicular. The riveting product is subjected to fatigue test installation and loading by means of the auxiliary tool and corresponding equipment for riveting product fatigue test installation and loading, so that the riveting product fatigue test meets the requirements of a test task. On the one hand, the fatigue test assembly precision is improved, and on the other hand, the test loading precision is improved. The improvement of assembly quality helps to ensure that the fatigue test reliability meets the requirements, the error is small during the riveting product fatigue test, and the stability of the riveting product fatigue test is improved.

Description

Technical Field

[0001] This invention belongs to the field of testing and experimentation, and relates to an auxiliary tooling and method for fatigue testing of riveted products. Background Technology

[0002] To verify the stability and reliability of fatigue performance of mass-produced parts, fatigue tests, i.e., routine batch fatigue tests, should be conducted on some key fatigue-prone components for product quality control. This helps to promptly identify various potential hazards of life-threatening parts during the mass production of helicopters, while ensuring the safe operation of helicopters in field service. According to helicopter product specifications, batch sampling fatigue tests must be conducted on riveted components in the main structure during mass production to ensure the quality of the helicopter's main structure and flight safety. Due to the complexity of the installation and force transmission of these riveted components, designing auxiliary tooling and finding a method to ensure accurate installation and simulation of the on-aircraft conditions to achieve correct force transmission during fatigue testing, and to ensure that the tests meet the requirements of the test schedule, is a technical challenge. This invention patent designs a dedicated auxiliary tooling and method for loading and installing riveted components during fatigue testing. Summary of the Invention

[0003] Purpose of the invention: The purpose of this invention is to provide an auxiliary tooling for loading during fatigue testing of riveted products and to find a method to ensure that the fatigue test of riveted products meets the requirements of the test schedule.

[0004] Technical solution

[0005] An auxiliary tooling for loading and installing riveted products during fatigue testing includes a loading joint assembly 1, a loading connection assembly 2, a riveting transition assembly 3, and a connecting seat 4. The loading joint assembly 1 is connected to the riveted product through the loading connection assembly 2, and the riveted product is installed onto the connecting seat 4 through the riveting transition assembly 3. The center of the axis of the loading joint assembly 1 is perpendicular to the center of the axis of the loading connection assembly 2.

[0006] The loading connector assembly 1 consists of a first washer 5, a first nut 6, and a connector 7. The first washer 5 and the first nut 6 are screwed onto the screw of the connector 7. The external thread of the screw of the connector 7 is screwed into the internal thread of the sensor 27, and then locked by the first washer 5 and the first nut 6.

[0007] The loading connection assembly 2 consists of a first bushing 13, a second bushing 14, a third bushing 15, a bearing 16, a fourth bushing 17, a fifth bushing 18, a third washer 19, a third nut 20, a second bolt 21, and a safety pin 22. The second bushing 14 and the third bushing 15 are fixed into one of the forks in the double-fork lug of the riveting product. The bearing 16 is fixed into the middle fork lug of the connector 7. The second bushing 14 and the first bushing 13 are fixed into one of the forks on either side of the connector 7. The fifth bushing... 18 is fixed in the other fork lug of the two fork lugs on both sides of the connector 7. The double fork lug of the riveting product is connected to the triple fork lug of the connector 7. The fourth bushing 17 is assembled with the bearing 16 at one end and the other fork lug of the double fork lug of the riveting product at the other end and the fifth bushing 18 is assembled. Then the second bolt 21 is passed through the first bushing 13, the third bushing 15, the bearing 16 and the fourth bushing 17 in sequence, and then fixed by the third washer 19 and the third nut 20. Finally, the safety pin 22 is inserted into the pin hole of the second bolt 21.

[0008] The riveting transition assembly 3 consists of a first bolt 8, a second washer 9, a second nut 10, a first transition plate 11, and a second transition plate 12. The riveting products are riveted to the first transition plate 11 and the second transition plate 12 respectively. The first transition plate 11 and the second transition plate 12 are installed on the connecting seat 4 by the first bolt 8, the second washer 9, and the second nut 10.

[0009] Furthermore, the connecting seat 4 is a machined integral part. The dimensions of the connecting seat 4 should ensure the installation dimensions after the riveting product is connected to the riveting transition component 3. It consists of a bottom cube and a trapezoidal cube. The bottom cube is equipped with six drilled holes to connect with the steel platform of the factory building. The side and top surfaces of the trapezoidal cube are respectively fitted to the riveting product. The side of the trapezoidal cube is milled with 12 holes, and the top surface is milled with 11 holes.

[0010] Furthermore, the first transition plate 11 is a T-shaped plate structure, with the middle part matching riveting products and equipped with riveting holes, and the edge part having holes drilled to connect with the connecting seat 4. The second transition plate 12 is a flat plate, with holes drilled at the top to connect with the connecting seat 4, and the lower part matching riveting products and equipped with riveting holes.

[0011] Furthermore, the material of connector 7 is 30CrMnSiA. Connector 7 is a forging, with a three-pronged lug structure at one end and a round bar structure at the other end. Part of the round bar is a smooth rod, and part is a threaded rod. There must be a transition section between the three-pronged lug structure and the round bar structure, and the connection between the round bar structure and the transition section is rounded. The three-pronged lug in connector 7 has three holes milled into two holes on both sides. center hole All surfaces are chamfered 1x45°, with a thickness of 6.5mm on both sides and 14.7mm in the middle. Two matching bushings are inserted into the holes on both sides, with the bushings having inner holes... The transition section between the three-pronged lug structure and the round bar structure in connector 7 is 20mm long, and the connection between the round bar structure and the transition section is rounded with a radius of R5.

[0012] Furthermore, the first nut 6 is made of 30CrMnSiA material. The bearing 16 is model XRL17R. There are 23 pieces each of the first bolt 8, the second washer 9, and the second nut 10.

[0013] Furthermore, the first transition plate 11 is made of 30CrMnSiA material, 12mm thick, with 12 φ8.5 holes drilled along its edge to connect with the connecting seat 4. The second transition plate 12 is also made of 30CrMnSiA material, 8mm thick, with 11 φ8.5 holes drilled on its upper part to connect with the connecting seat 4. Furthermore, the connecting seat 4 is made of Q235 material, with a dimensional tolerance of ±0.1.

[0014] A fatigue testing method for riveted products includes the following steps:

[0015] Step 1: Build an experimental system, which includes driver software 23, servo controller 24, servo valve 25, actuator 26, sensor 27, constant pressure servo pump station 28, and substation oil distribution module 29. This experimental system is a closed-loop servo control system. The driver software 23 sends commands to the servo controller 24, which drives the servo valve 25, thereby controlling the actuator 26. At the same time, the servo controller 24 controls the substation oil distribution module 29 to supply and discharge oil to the actuator 26, pushing the piston rod of the actuator 26 to actuate. On the other hand, the sensor 27 measures the load, and the measured value is fed back to the servo controller. The theoretical value and the actual value are compared, and the error is reduced to the minimum range for load control.

[0016] The experimental steps are as follows:

[0017] Step 2: Rivet the riveted products to the first transition plate 11 and the second transition plate 12 in the riveting transition assembly 3 respectively. When installing the rivets, the total thickness of the connected parts at the rivet hole should be measured first, and the appropriate length of rivet should be selected according to the total thickness.

[0018] Step 3: Fix the connecting seat 4 to the steel platform, and connect the riveted transition component 3, which is riveted to the riveted product, to the connecting seat 4 with bolts.

[0019] Step 4: Check the condition of the testing equipment and instruments to ensure that they are within their calibration validity period.

[0020] Step 5: Place sensor 27 flat on the ground, connect the servo controller 24 channel line, calibrate the servo controller 24 using the sensor 27 calibration report on the driver software 23, and clear zero drift.

[0021] Step 6: Connect the loading connector assembly 1 to the internal threaded hole of the sensor 27. The sensor 27 is screwed to the piston rod connector of the actuator 26. The tail end of the actuator is fixed on the support. The support is fixed on the steel platform. The center of the actuator 26 shaft and the center of the screw shaft of the connector 7 are on the same center line, and the coaxiality does not exceed 1°.

[0022] Step 7: Install the displacement sensor onto the actuator 26, calibrate the servo controller 24 by measuring the displacement, adjust the piston rod of the actuator 26 by adjusting the displacement sensor, adjust the three-pronged lug of the connector 7 to the double-pronged lug hole of the riveting product, connect the riveting product to the connector 7 by loading the connecting component 2, and ensure that the positions on both sides are balanced.

[0023] Step 8: Apply dry tightening torque to the third nut 20 and connect the safety pin 22.

[0024] Step 9: After installation, use a laser tracker to perform laser testing on the installation of the riveted products for fatigue testing: it should conform to the requirements of the fatigue test outline for riveted products, with an error not exceeding 1°.

[0025] Step 10: Open the driver software 23 and start the constant pressure servo pump station 28.

[0026] Step 11: Compile the load spectrum and set protection parameters for the load and displacement. The system will automatically unload if the load exceeds the tolerance.

[0027] Step 12: Adjust the system PID parameters using a small load.

[0028] Step 13: Debug the test with a small load.

[0029] Step 14: After the test is completed normally, stop the debugging.

[0030] Step 15: If any abnormal noises or other abnormalities occur during debugging, use the emergency stop device to immediately stop the test. Check the riveted products, test fixtures, and test specimens for cracks and damage, and the condition of the test equipment. Record the inspection results. Furthermore, the drive software 23 in Step 1 includes software modules: system configuration software, test management software, rapid debugging software, data storage and post-processing display software, and complex load spectrum automatic creation software. The servo controller 24 has an accuracy of ≤1% for static and ≤2% for dynamic operation. The actuator 26 has a displacement sensor with a load of 5T and a stroke of 200mm. The sensor 27 has a load of 5T and is a BK-1 type. The constant pressure servo pump station 28 has a rated flow rate of 800L / min and a system working pressure of 21MPa.

[0031] Furthermore, the tightening torque of the third nut 20 in step eight is 84.6~103.4Nm.

[0032] Furthermore, in step twelve, the small load is ±1KN, and the adjustment frequency is 0.5Hz. In step thirteen, the small load is ±5KN, and the adjustment frequency is 1Hz.

[0033] Technical effect

[0034] By utilizing auxiliary tooling and corresponding equipment for fatigue testing of riveted products, fatigue testing of these products is performed, ensuring that the fatigue tests meet the requirements of the test specifications. This improves both the assembly accuracy and the loading accuracy of the test. The improved assembly quality helps ensure the reliability of the fatigue test, resulting in smaller errors and enhanced stability during fatigue testing of riveted products. This method can also be applied to fatigue testing of other riveted products requiring high-precision assembly quality. Attached Figure Description

[0035] Figure 1 Main view of the structure;

[0036] Figure 2 Top view of the structure;

[0037] Figure 3 Structural lateral view;

[0038] Figure 4 3D view of the riveted transition component;

[0039] Figure 5 3D view of connector 4;

[0040] Figure 6 Load the schematic diagram;

[0041] Figure 7 PID control diagram. Detailed Implementation

[0042] The present invention will be further described below with reference to embodiments. The following description represents only a portion of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0043] An auxiliary tooling for fatigue testing of riveted products includes a loading joint assembly 1, a loading connection assembly 2, a riveting transition assembly 3, and a connecting seat 4. The loading joint assembly 1 is connected to the riveted product through the loading connection assembly 2, and the riveted product is installed on the connecting seat 4 through the riveting transition assembly 3. The center of the axis of the loading joint assembly 1 is perpendicular to the center of the axis of the loading connection assembly 2.

[0044] The loading connector assembly 1 consists of a first washer 5, a first nut 6, and a connector 7. The first washer 5 and the first nut 6 are screwed onto the screw of the connector 7. The external thread of the screw of the connector 7 is screwed into the internal thread of the sensor 27, and then locked by the first washer 5 and the first nut 6.

[0045] Joint 7 is a forging with a three-pronged lug structure on one end and a round bar structure on the other. Part of the round bar is a smooth rod and part is a screw. There must be a transition section between the three-pronged lug structure and the round bar structure. The connection between the round bar structure and the transition section is rounded.

[0046] The loading connection assembly 2 consists of a first bushing 13, a second bushing 14, a third bushing 15, a bearing 16, a fourth bushing 17, a fifth bushing 18, a third washer 19, a third nut 20, a second bolt 21, and a safety pin 22. The second bushing 14 and the third bushing 15 are fixed into one of the forks in the double-fork lug of the riveting product. The bearing 16 is fixed into the middle fork lug of the connector 7. The second bushing 14 and the first bushing 13 are fixed into one of the forks on either side of the connector 7. The fifth bushing... 18 is fixed in the other fork lug of the two fork lugs on both sides of the connector 7. The double fork lug of the riveting product is connected to the triple fork lug of the connector 7. The fourth bushing 17 is assembled with the bearing 16 at one end and the other fork lug of the double fork lug of the riveting product at the other end and the fifth bushing 18 is assembled. Then the second bolt 21 is passed through the first bushing 13, the third bushing 15, the bearing 16 and the fourth bushing 17 in sequence, and then fixed by the third washer 19 and the third nut 20. Finally, the safety pin 22 is inserted into the pin hole of the second bolt 21.

[0047] The riveting transition assembly 3 consists of a first bolt 8, a second washer 9, a second nut 10, a first transition plate 11, and a second transition plate 12. The riveting products are riveted to the first transition plate 11 and the second transition plate 12 respectively. The first transition plate 11 and the second transition plate 12 are installed on the connecting seat 4 by the first bolt 8, the second washer 9, and the second nut 10.

[0048] The connecting seat 4 is a machined integral part. The dimensions of the connecting seat 4 should ensure the installation dimensions after the riveting product is connected to the riveting transition component 3. The connecting seat 4 consists of a bottom cube and a trapezoidal cube. The bottom cube is equipped with six drilled holes to connect with the steel platform of the factory building. The side and top surfaces of the trapezoidal cube are respectively fitted to the riveting product. The side of the trapezoidal cube is milled with 12 holes, and the top surface is milled with 11 holes.

[0049] The first transition plate 11 is a T-shaped plate structure. The middle part is matched with riveting products and is equipped with riveting holes. The edge part is drilled with holes to connect with the connecting seat 4.

[0050] The second transition plate 12 is a flat plate with holes drilled in the upper part to connect with the connecting seat 4, and the lower part is matched with riveting products and equipped with riveting holes.

[0051] A fatigue testing method for riveted products includes the following steps:

[0052] Step 1: Build an experimental system, which includes driver software 23, servo controller 24, servo valve 25, actuator 26, sensor 27, constant pressure servo pump station 28, and substation oil distribution module 29. This experimental system is a closed-loop servo control system. The driver software 23 sends commands to the servo controller 24, which drives the servo valve 25, thereby controlling the actuator 26. At the same time, the servo controller 24 controls the substation oil distribution module 29 to supply and discharge oil to the actuator 26, pushing the piston rod of the actuator 26 to actuate. On the other hand, the sensor 27 measures the load, and the measured value is fed back to the servo controller. The theoretical value and the actual value are compared, and the error is reduced to the minimum range for load control.

[0053] The experimental steps are as follows:

[0054] Step 2: Rivet the riveted products to the first transition plate 11 and the second transition plate 12 in the riveting transition assembly 3 respectively. When installing the rivets, the total thickness of the connected parts at the rivet hole should be measured first, and the appropriate length of rivet should be selected according to the total thickness.

[0055] Step 3: Fix the connecting seat 4 to the steel platform, and connect the riveted transition component 3, which is riveted to the riveted product, to the connecting seat 4 with bolts.

[0056] Step 4: Check the condition of the testing equipment and instruments to ensure that they are within their calibration validity period.

[0057] Step 5: Place sensor 27 flat on the ground, connect the servo controller 24 channel line, calibrate the servo controller 24 using the sensor 27 calibration report on the driver software 23, and clear zero drift.

[0058] Step 6: Connect the loading connector assembly 1 to the internal threaded hole of the sensor 27. The sensor 27 is screwed to the piston rod connector of the actuator 26. The tail end of the actuator is fixed on the support. The support is fixed on the steel platform. The center of the actuator 26 shaft and the center of the screw shaft of the connector 7 are on the same center line, and the coaxiality does not exceed 1°.

[0059] Step 7: Install the displacement sensor onto the actuator 26, calibrate the servo controller 24 by measuring the displacement, adjust the piston rod of the actuator 26 by adjusting the displacement sensor, adjust the three-pronged lug of the connector 7 to the double-pronged lug hole of the riveting product, connect the riveting product to the connector 7 by loading the connecting component 2, and ensure that the positions on both sides are balanced.

[0060] Step 8: Apply dry tightening torque to the third nut 20 and connect the safety pin 22.

[0061] Step 9: After installation, use a laser tracker to perform laser testing on the installation of the riveted products for fatigue testing: it should conform to the requirements of the fatigue test outline for riveted products, with an error not exceeding 1°.

[0062] Step 10: Open the driver software 23 and start the constant pressure servo pump station 28.

[0063] Step 11: Compile the load spectrum and set protection parameters for the load and displacement. The system will automatically unload if the load exceeds the tolerance.

[0064] Step 12: Adjust the system PID parameters using a small load.

[0065] Step 13: Debug the test with a small load.

[0066] Step 14: After the test is completed normally, stop the debugging.

[0067] Step 15: If any abnormal noise or other abnormal situation occurs during the debugging process, use the emergency stop device to immediately stop the test, check whether the riveted products, test fixtures, test specimens have cracks and damage, and check the condition of the test equipment, and record the inspection results.

[0068] Furthermore, in connector 7, the two side holes of the three holes in the three-pronged ear are milled. center hole All surfaces are chamfered 1x45°, with a thickness of 6.5mm on both sides and 14.7mm in the middle. Two matching bushings are inserted into the holes on both sides, with the bushings having inner holes...

[0069] Furthermore, in connector 7, the transition section between the three-pronged lug structure and the round bar structure is 20mm long and 66mm wide, and the connection between the round bar structure and the transition section is rounded with a radius of R5.

[0070] Furthermore, in connector 7, the two side holes of the three holes in the three-pronged ear are milled. center hole All chamfers are 1x45°, the thickness on both sides is 6.5mm, and the thickness in the middle is 14.7mm.

[0071] Furthermore, the first nut 6 is made of 30CrMnSiA material.

[0072] Furthermore, the first gasket 5 is 30GB95, and the first nut 6 is M30x2.

[0073] Furthermore, bearing model 16 is XRL17R.

[0074] Furthermore, there are 23 pieces each of the first bolt 8, the second washer 9, and the second nut 10.

[0075] Furthermore, the first transition plate 11 is made of 30CrMnSiA material, 12mm thick, and has 12 φ8.5 holes drilled at its edge to connect with the connecting seat 4.

[0076] Furthermore, the second transition plate 12 is made of 30CrMnSiA material, 8mm thick, and has 11 φ8.5 holes drilled in the upper part to connect with the connecting seat 4.

[0077] Furthermore, the material of the connector 4 is Q235, and the dimensional tolerance of the profile is ±0.1.

[0078] Furthermore, in step one, the driving software 23 includes software modules: system configuration software, test management software, quick debugging software, data storage post-processing and display software, complex load spectrum automatic creation software, etc.; servo controller 24 accuracy: static ≤1%, dynamic ≤2%; actuator 26 with displacement sensor, load 5T, stroke 200mm; sensor 27 load 5T, BK-1 type; constant pressure servo pump station 28 rated flow 800L / min, system working pressure 21Mpa.

[0079] Furthermore, in step two, the installation of the fatigue test specimens for riveted products is consistent with the assembly on the helicopter, and the connection stiffness of the fixed end of the test specimen should simulate the real situation as much as possible.

[0080] Furthermore, the tightening torque of the third nut 20 in step eight is 84.6~103.4Nm.

[0081] Furthermore, in step twelve, first set I and D to 0, then adjust P. The value of P should not be too large at the beginning, and should be increased gradually. Under load and deformation control, P is generally within 10%, and can reach more than 80% under displacement control. Then adjust I. When adjusting I, P can be fine-tuned. Finally, adjust D. When adjusting D, P and I can be fine-tuned. Usually, PID adjustment should be carried out in conjunction. Observe the waveform during adjustment to make the actual loading waveform consistent with or close to the theoretical loading waveform, ensuring that the loading error is ≤3%, so that the test can run as stably, normally, continuously and safely as possible.

[0082] Furthermore, in step twelve, the small load is ±1KN, and the adjustment frequency is 0.5Hz.

[0083] Furthermore, in step thirteen, the small load is ±5KN, and the adjustment frequency is 1Hz.

[0084] Furthermore, in step thirteen, the test is adjusted under small loads. Because there is air in the oil pipe, the load will rise sharply even before the test begins, which will have a great impact on the test piece. Therefore, the load change should be observed during pressure adjustment, and attention should be paid to the influence of oil pressure on the load.

[0085] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein. The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An auxiliary tooling for fatigue testing and loading of riveted products, characterized in that, It includes a loading connector assembly, a loading connection assembly, a riveting transition assembly, and a connecting seat. The loading connector assembly is connected to the riveting product through the loading connection assembly, and the riveting product is installed on the connecting seat through the riveting transition assembly. The axis center of the loading connector assembly is perpendicular to the axis center of the loading connection assembly. The loading connector assembly consists of a first washer, a first nut, and a connector. The first washer and the first nut are screwed onto the screw of the connector. The external thread of the screw of the connector is screwed into the internal thread of the BK-1 type sensor, and then locked by the first washer and the first nut. The loading connection assembly consists of a first bushing, a second bushing, a third bushing, a bearing, a fourth bushing, a fifth bushing, a third washer, a third nut, a second bolt, and a safety pin. The second and third bushings are fixed in one of the forks of the double fork lug of the riveting product. The bearing is fixed in the middle fork lug of the joint. The second and first bushings are fixed in one of the forks on both sides of the joint. The fifth bushing is fixed in the other fork lug on both sides of the joint. The double fork lug of the riveting product is connected to the three fork lug of the joint. The fourth bushing, with one end supporting the bearing, is assembled with the other fork lug of the double fork lug of the riveting product, and the other end is assembled with the fifth bushing. Then, the second bolt is passed through the first bushing, the third bushing, the bearing, and the fourth bushing in sequence, and then fixed by the third washer and the third nut. Finally, the safety pin is inserted into the pin hole of the second bolt. The riveting transition assembly consists of a first bolt, a second washer, a second nut, a first transition plate, and a second transition plate. The riveting products are riveted to the first transition plate and the second transition plate respectively. The first transition plate and the second transition plate are installed onto the connecting seat by the first bolt, the second washer, and the second nut.

2. The auxiliary tooling for fatigue testing and loading of riveted products according to claim 1, characterized in that, The connector is a machined integral part. The dimensions of the connector should ensure the installation dimensions after the riveting product is connected to the riveting transition component. It consists of a bottom cube and a trapezoidal cube. The bottom cube is equipped with six drilled holes to connect with the steel platform of the factory building. The sides and top surfaces of the trapezoidal cube are respectively fitted to the riveting product. The sides of the trapezoidal cube are milled with 12 holes, and the top surface is milled with 11 holes.

3. The auxiliary tooling for fatigue testing and loading of riveted products according to claim 1, characterized in that, The first transition plate is a T-shaped plate structure, with the middle part matching riveting products and equipped with riveting holes, and the edge part being drilled to connect with the connecting seat; the second transition plate is a flat plate, with holes drilled at the top to connect with the connecting seat, and the bottom part matching riveting products and equipped with riveting holes.

4. The auxiliary tooling for fatigue testing and loading of riveted products according to claim 1, characterized in that, The joint material is 30CrMnSiA; the joint is a forging, with a three-pronged lug structure on one end and a round bar structure on the other end. Part of the round bar is a smooth rod and part is a screw. There must be a transition section between the three-pronged lug structure and the round bar structure. The connection between the round bar structure and the transition section is rounded. The three holes in the connector are milled on both sides. 31H7, center hole 30K7, with a 1x45° chamfer on both sides, a thickness of 6.5mm on both sides, and a thickness of 14.7mm in the middle. Two matching bushings are inserted into the holes on both sides. The inner holes of the bushings... 21C8; The transition section between the three-pronged lug structure and the round bar structure in the connector is 20mm long, and the connection between the round bar structure and the transition section is rounded with an radius of R5.

5. The auxiliary tooling for fatigue testing and loading of riveted products according to claim 1, characterized in that, The material of the first nut is 30CrMnSiA; the bearing model is XRL17R; there are 23 pieces each of the first bolt, the second washer, and the second nut.

6. The auxiliary tooling for fatigue testing and loading of riveted products according to claim 1, characterized in that, The first transition plate is made of 30CrMnSiA material, 12mm thick, with 12 Φ8.5 holes drilled on the edge to connect with the connecting seat; the second transition plate is made of 30CrMnSiA material, 8mm thick, with 11 Φ8.5 holes drilled on the upper part to connect with the connecting seat.

7. The auxiliary tooling for fatigue testing and loading of riveted products according to claim 2, characterized in that, The connector is made of Q235 steel, and its dimensional tolerance is ±0.

1.

8. A fatigue test loading method for riveted products using the auxiliary tooling described in any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Build a test system. The test system includes drive software, servo controller, servo valve, actuator, BK-1 type sensor, constant pressure servo pump station, and substation oil distribution module. This test system is a closed-loop servo control system. The drive software sends commands to the servo controller, which drives the servo valve and then controls the actuator. At the same time, the servo controller sends commands to the substation oil distribution module to control the oil flow into and out of the actuator, pushing the actuator piston rod to move. On the other hand, the BK-1 type sensor measures the load, and the measured value is fed back to the servo controller. The theoretical value and the actual value are compared, and the error is reduced to the minimum range for load control. Step 2: Rivet the riveted products to the first transition plate and the second transition plate in the riveting transition assembly. When installing the rivets, the total thickness of the connected parts at the rivet hole should be measured first, and the appropriate length of rivet should be selected according to the total thickness. Step 3: Fix the connecting seat to the steel platform, and connect the riveted transition component that has been riveted to the riveted product to the connecting seat using bolts; Step 4: Check the condition of the testing equipment and instruments to ensure they are within their calibration validity period; Step 5: Place the BK-1 sensor flat on the ground, connect the servo controller channel cable, calibrate the servo controller using the BK-1 sensor calibration report in the driver software, and clear zero drift. Step 6: Connect the loading connector assembly to the internal threaded hole of the BK-1 type sensor. The BK-1 type sensor is screwed to the actuator piston rod connector. The tail end of the actuator is fixed on the support. The support is fixed on the steel platform. The center of the actuator shaft and the center of the connector screw shaft are on the same center line, and the coaxiality does not exceed 1°. Step 7: Install the displacement sensor onto the actuator, calibrate the servo controller by measuring the displacement, adjust the actuator piston rod by adjusting the displacement sensor, adjust the three-pronged lug of the connector to the double-pronged lug hole of the riveting product, connect the riveting product to the connector by loading the connecting assembly, and ensure that the positions on both sides are balanced. Step 8: Apply dry tightening torque to the third nut and connect the safety pin; Step 9: After installation, use a laser tracker to perform laser testing on the installation of the riveted products for fatigue testing: it should conform to the requirements of the fatigue test outline for riveted products, with an error not exceeding 1°; Step 10: Open the driver software and start the constant pressure servo pump station; Step 11: Compile the load spectrum, set protection parameters for load and displacement, and the system will automatically unload if the load exceeds the tolerance. Step 12: Adjust the system PID parameters using a small load; Step 13: Adjust the test using a small load; Step 14: After the test is completed normally, stop the debugging. Step 15: If any abnormal noise occurs during the test, use the emergency stop device to immediately stop the test, check whether the riveted products, test fixtures, and test specimens have cracks or damage, and check the condition of the test equipment, and record the inspection results. The driving software in step one includes the following software modules: system configuration software, test management software, quick debugging software, data storage post-processing and display software, and complex load spectrum automatic creation software. The servo controller accuracy is ≤1% for static and ≤2% for dynamic. The actuator has a displacement sensor with a load of 5T and a stroke of 200mm. The BK-1 type sensor has a load of 5T. The constant pressure servo pump station has a rated flow of 800L / min and a system working pressure of 21MPa.

9. The fatigue test installation and loading method for riveted products according to claim 8, characterized in that, The tightening torque of the third nut in step eight is 84.6~103.4Nm.

10. The fatigue test installation and loading method for riveted products according to claim 8, characterized in that, In step twelve, the small load is ±1KN, and the adjustment frequency is 0.5Hz; in step thirteen, the small load is ±5KN, and the adjustment frequency is 1Hz.

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