A fatigue durability test device for a rivet structure

Abstract

The present application relates to the technical field of fatigue durability test, and particularly relates to a fatigue durability test device for rivet structure, comprising: two detection components, the two detection components are symmetrically arranged, and a first air pump is arranged between the two detection components; wherein the detection component comprises: a cover cylinder, a supporting assembly, a rotary driving assembly, a linear driving assembly and a pressure detection module. The durability of the rivet can be known through the pressure change when the cover cylinder is supplied with air by the pressure detection module. That is, the alternating stress of the rivet in the actual working condition is simulated by the rotary driving assembly, air is supplied into the cover cylinder by the first air pump, and the pressure fluctuation caused by the clearance change between the rivet and the riveting piece is monitored by the pressure detection module, so that the durability of the rivet is determined.

Description

Technical Field

[0001] This invention relates to the field of fatigue durability testing technology, and specifically to a fatigue durability testing device for rivet structures. Background Technology

[0002] In industrial sectors such as aerospace, rail transportation, automobile manufacturing, heavy machinery, and building structures, riveting technology, as a classic and reliable connection method, is widely used in the assembly of various metal structural components due to its mature technology, high connection strength, and good vibration resistance. As a core component of the connection, the rivet's service condition directly affects the safety and service life of the overall structure. During actual flight, rivets on the aircraft surface are in an unsteady flow field. Pressure fluctuations, turbulent disturbances, and vortex-induced vibrations in the airflow apply high-frequency, random, micro-amplitude loads to the rivets. This fretting fatigue caused by the direct action of airflow is one of the core factors leading to seal failure and structural loosening.

[0003] Therefore, a scientific and accurate fatigue durability assessment of rivet structures is crucial. Traditional fatigue testing methods typically employ hydraulic or mechanical actuators to apply cyclic loads to the specimen. However, these devices often suffer from drawbacks such as large size, system complexity, limited ability to simulate the test environment (e.g., difficulty in simultaneously applying or precisely controlling complex environmental loads, such as alternating aerodynamics or corrosion fatigue under specific media conditions), and high testing costs. In particular, for tests requiring simulation of rivets under alternating stress conditions in specific air pressure or sealed environments, existing devices often lack integrated environmental simulation and load application design.

[0004] Existing testing equipment suffers from limitations in specimen clamping, alignment, real-time monitoring of the testing process (such as clamping force, environmental pressure, and stress state), and intuitive data feedback. These limitations include insufficient flexibility, low automation, and poor information visualization, affecting testing efficiency and the accuracy of results. Furthermore, in aerospace, high-speed train, and other aerodynamic fields, rivet structures are constantly exposed to high-speed airflow, enduring high-frequency fretting or vibration loads induced by aerodynamic pressure fluctuations. This aerodynamic fretting fatigue, combined with mechanical alternating stress, significantly accelerates the rivet's damage process. However, traditional fatigue testing equipment typically only applies mechanical loads, lacking the ability to simultaneously apply and couple with aerodynamic environmental loads. This results in significant discrepancies between test conditions and actual operating conditions, making it difficult to accurately assess the durability of rivets under real combined loads.

[0005] Therefore, there is a need to provide a fatigue durability testing device for rivet structures to solve the above problems. Summary of the Invention

[0006] To address the shortcomings of existing technologies in terms of insufficient flexibility, low automation, or poor information visualization in specimen clamping, alignment adjustment, real-time monitoring of the testing process (such as clamping force, environmental pressure, stress state, etc.), and intuitive data feedback, this invention provides a fatigue durability testing device for rivet structures to solve these problems.

[0007] The first aspect of the present invention provides a fatigue durability testing apparatus for rivet structures, the apparatus employing the following technical solution, comprising:

[0008] Two detection components are arranged symmetrically, and a first air pump is installed between the two detection components;

[0009] The detection components include:

[0010] The cover has an opening at one end and a ring is fixedly fitted on its outside. The inner ring of the ring is connected to the inside of the cover. The two ports of the first air pump are respectively connected to the rings corresponding to the detection components.

[0011] A support assembly is located on one side of the cover;

[0012] A rotary drive assembly is slidably mounted on a support assembly along the axial direction of the cover. Its output end coaxially passes through the closed end of the cover and connects to a clamping plate inside the cover. It is used to drive the clamping plate to rotate.

[0013] A linear drive assembly is used to drive the rotary drive assembly to move so that the clamps of the two detection components move towards each other;

[0014] And a pressure detection module, which is installed in the shroud to detect the gas pressure inside the shroud.

[0015] A further technical solution of the present invention is that a sealing ring is provided on the opposite end face of the two cover cylinders. The sealing ring is used to seal the contact surface between the cover cylinder and the riveting component when the ends of the rivets are clamped by the two clamping plates.

[0016] A further technical solution of the present invention includes a U-shaped clamp with a rubber layer on its clamping surface for clamping the sealing rings of the two covers.

[0017] A further technical solution of the present invention is that the support component includes: a U-shaped guide frame, the end of which is fixedly connected to the side of the ring sleeve, wherein the rotation drive component is slidably disposed between the U-shaped areas of the U-shaped guide frame.

[0018] A further technical solution of the present invention is that the rotary drive assembly adopts a motor, and a connecting rod is arranged radially on the motor. The end of the connecting rod away from the motor is slidably connected to the guide rod of the U-shaped guide frame through a sliding sleeve.

[0019] A further technical solution of the present invention is that the linear drive assembly includes: a positioning plate, which is disposed on one side of the U-shaped guide frame, a baffle is disposed on the side of the positioning plate facing the motor, an airbag is disposed between the baffle and the end of the motor away from the output end, a second air pump is disposed on the side of the positioning plate away from the airbag, and the output end of the second air pump is connected to the airbag.

[0020] A further technical solution of the present invention is that the positioning plate is connected to the U-shaped guide frame through a positioning ring.

[0021] A further technical solution of the present invention is that an installation tube is connected to the ring sleeve, one end of the installation tube is connected to the ring sleeve, and the other end of the installation tube is connected to the first air pump.

[0022] A further technical solution of the present invention is that a support rod is connected to the installation tube, and a display is installed on the support rod. The display is connected to a corresponding pressure detection module through wires.

[0023] A further technical solution of the present invention is that the pressure detection module adopts a pressure detector, the detection end of the pressure detector is located inside the corresponding cover, and the pressure detector and the display are electrically connected.

[0024] The beneficial effects of this invention are:

[0025] This invention utilizes a first air pump 1 to continuously supply controlled airflow, not only for monitoring but, more importantly, to apply "pneumatic loading" to the rivet end through high-speed airflow. This continuous airflow disturbance, combined with the rotational load of the motor, creates a mechanical-pneumatic coupled fatigue environment. Secondly, a rotary drive assembly rotates the clamping plates, thereby driving the rivet to rotate at high speed. Changes in the gap between the rivet and the riveted part reflect the fatigue durability state of the rivet. Simultaneously, a linear drive assembly controls the linear movement of the rotary drive assembly, causing the two clamping plates to move towards each other and clamp the rivet. The cover and the surface of the riveted part form a sealed space. When gas is introduced, a pressure detection module detects changes in the gas pressure inside the cover to determine the fatigue durability of the rivet. Furthermore, the sealing ring on the end face of the cover ensures contact between the sealing ring and the surface of the riveted part, further increasing the sealing performance and making the monitoring more accurate. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1This is a schematic diagram of the overall structure of a fatigue durability testing device for rivet structures according to the present invention;

[0028] Figure 2 for Figure 1 Schematic diagram of the structure of the detection component;

[0029] Figure 3 This is a side view of the second air pump in conjunction with the positioning plate.

[0030] Figure 4 This is a schematic diagram showing the fit between the cover and the riveted parts;

[0031] Figure 5 This is a schematic diagram of the airflow direction in this invention;

[0032] Figure 6 This is a diagram showing the state of the fatigue durability testing device for rivet structures according to the present invention during testing.

[0033] Figure 7 This is a partial cross-sectional view of the cover during the testing of a fatigue durability testing device for rivet structures according to the present invention.

[0034] In the diagram: 1. First air pump; 2. Output shaft; 3. Clamping plate; 4. Sealing ring; 5. Cover; 6. Ring sleeve; 7. Support rod; 8. Display; 9. Positioning component; 10. Wire; 11. Motor; 12. Sliding sleeve; 13. Connecting rod; 14. Airbag; 15. Baffle; 16. Positioning plate; 17. Positioning ring; 18. U-shaped guide frame; 19. Pressure detector; 20. Second air pump. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] An embodiment of the fatigue durability testing device for rivet structures according to the present invention, such as... Figure 1 As shown, it includes: two detection components A, which are symmetrically arranged, and a first air pump 1 is disposed between the two detection components A. Detection component A includes: a cover 5, a support assembly, a rotary drive assembly, a linear drive assembly, and a pressure detection module; one end of the cover 5 is open, as shown... Figure 2 and 4As shown, a ring 6 is fixedly fitted on the outside of the cover cylinder 5. The inner ring of the ring 6 is connected to the inside of the cover cylinder 5. The two ports of the first air pump 1 are respectively connected to the ring 6 corresponding to the detection component A. The support assembly is set on one side of the cover cylinder 5. The rotary drive assembly is slidably set on the support assembly along the axial direction of the cover cylinder 5. The output end of the rotary drive assembly passes coaxially through the closed end of the cover cylinder 5 and is connected to the clamping plate 3 set inside the cover cylinder 5. The rotary drive assembly is used to drive the clamping plate 3 to rotate. The linear drive assembly is used to drive the rotary drive assembly to move so that the clamping plates 3 of the two detection components A move towards each other to clamp the two ends of the rivet on the riveting part. The pressure detection module is set on the cover cylinder 5 and is used to detect the gas pressure inside the cover cylinder 5.

[0037] For example, in one specific embodiment, sealing rings 4 are provided on the opposite end faces of the two cover cylinders 5. The sealing rings 4 are used to seal the contact surface between the cover cylinder 5 and the riveting component when the ends of the rivets are clamped by the two clamping plates 3. Figure 6 As shown, the sealing rings of the two covers are clamped by a U-shaped clamp to enhance the sealing performance. Specifically, the U-shaped clamp includes a U-shaped component with two hand-tightening screws. The ends of the two hand-tightening screws pass through the U-shaped component and enter the U-shaped groove, and the ends of the two hand-tightening screws are opposite each other. A clamping plate is provided on the opposite ends of the hand-tightening screws, and a rubber layer is provided on the clamping plate.

[0038] For example, in one specific embodiment, the support component includes: a U-shaped guide frame 18, the end of which is fixedly connected to the side of the ring 6, wherein the rotation drive component is slidably disposed between the U-shaped areas of the U-shaped guide frame 18.

[0039] For example, in one specific embodiment, the rotary drive assembly adopts a motor 11, and a connecting rod 13 is arranged radially on the motor 11. The end of the connecting rod 13 away from the motor 11 is slidably connected to the guide rod of the U-shaped guide frame 18 through a sliding sleeve 12. The output shaft 2 of the motor 11 passes through the closed end of the cover 5 and is connected to the clamping plate 3. The output shaft 2 and the closed end of the cover 5 are connected by a movable seal.

[0040] For example, in one specific embodiment, the linear drive assembly includes: a positioning plate 16 disposed on one side of the U-shaped guide frame 18, a baffle 15 disposed on the side of the positioning plate facing the motor 11, and an airbag 14 disposed between the baffle 15 and the end of the motor 11 opposite to the output end. Figure 3 As shown, a second air pump 20 is provided on the side of the positioning plate 16 away from the airbag 14, and the output end of the second air pump 20 is connected to the airbag 14.

[0041] For example, in one specific embodiment, the positioning plate 16 is connected to the U-shaped guide frame 18 via the positioning ring 17.

[0042] For example, in one specific embodiment, an installation tube is connected to the ring 6, one end of the installation tube is connected to the ring 6, and the other end of the installation tube is connected to the first air pump 1.

[0043] For example, in one specific embodiment, a support rod 7 is connected to the mounting tube, and a display 8 is mounted on the support rod 7. The display 8 is connected to a corresponding pressure detection module via a wire 10, wherein, as shown... Figure 2 As shown, the display 8 is connected to the support rod 7 via the positioning element 9.

[0044] For example, in one specific embodiment, the pressure detection module uses a pressure detector 19, and the detection end of the pressure detector 19 is located inside the corresponding cover 5.

[0045] Working principle

[0046] This device continuously supplies controlled airflow through a first air pump 1, not only for monitoring but, more importantly, to apply "pneumatic loading" to the rivet end using high-speed airflow. This continuous airflow disturbance, combined with the rotating load of the motor, creates a mechanical-pneumatic coupled fatigue environment. Figure 5 , Figure 6 and Figure 7As shown, the first air pump 1 is connected to the detection component A by a flexible hose, which does not affect the movement of the two detection components A. In specific operation, the covers 5 of the two detection components A are first placed over the left and right ends of the rivet, and the sealing rings on the covers 5 are pressed against the outer surface of the riveted parts. The second air pump 20 is controlled to inflate the airbag 14, causing the airbag 14 to expand and drive the motor 11 to move. This causes the two clamping plates 3 on the output shaft 2 of the motor 11 to move towards each other to clamp the end of the rivet. Then, the motor 11 is started, and the motor 11 will drive the output shaft 2 to rotate, which in turn drives the clamping plates 3 to rotate. By controlling the speed of the motor 11, the clamping plates 3 drive the rivet to rotate at high speed, applying basic torsional alternating stress to the rivet. At the same time, the first air pump 1 is started, introducing a constant or set frequency pulsating airflow into one of the covers 5. This airflow simulates the aerodynamic pressure in the real environment, applying additional aerodynamic micro-motion excitation to the rivet. Under combined loads, if the rivet suffers fatigue damage (such as microcrack initiation or loosening), the gap between it and the riveted parts will change, immediately affecting the airflow characteristics through the gap. At this time, when air is pumped into the sleeve 5 of the left-side detection component A via the first air pump, the airflow will more easily flow through the increased gap to the right-side detection component A, causing an increase in air pressure inside the right-side sleeve 5, and a corresponding increase in the reading of the pressure detector 19. Conversely, if the rivet has good durability, the gap change is small, the airflow is obstructed, and the change in the reading of the right-side pressure detector 19 is smaller. By capturing this air pressure signal in real time through the pressure detection module, its trend and amplitude can directly reflect the cumulative state of rivet fatigue damage. This invention, by integrating mechanical rotation and pneumatic loading, for the first time realizes the simulation of multi-axis combined fatigue loads on rivets in a single device, and through airflow—a medium with both loading and sensing functions—achieves sensitive, in-situ, and real-time monitoring of fatigue damage.

[0047] The above description is merely a preferred embodiment of the present invention and is 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 protection scope of the present invention.

Claims

1. A fatigue durability testing device for rivet structures, characterized in that, include: Two detection components are arranged symmetrically, and a first air pump is installed between the two detection components; The detection components include: The cover has an opening at one end and a ring is fixedly fitted on its outside. The inner ring of the ring is connected to the inside of the cover. The two ports of the first air pump are respectively connected to the rings corresponding to the detection components. A support assembly is located on one side of the cover; A rotary drive assembly is slidably mounted on a support assembly along the axial direction of the cover. Its output end coaxially passes through the closed end of the cover and connects to a clamping plate inside the cover. It is used to drive the clamping plate to rotate. A linear drive assembly is used to drive the rotary drive assembly to move so that the clamps of the two detection components move towards each other; And a pressure detection module, which is installed in the shroud to detect the gas pressure inside the shroud; The first air pump supplies airflow inside the casing, which applies pneumatic excitation to the rivet. The airflow and the torsional alternating stress applied by the rotation drive component together constitute a mechanical-pneumatic coupling fatigue environment. At the same time, the airflow serves as a detection medium, and the pressure detection module monitors in real time the air pressure fluctuations caused by the change in the gap between the rivet and the riveted part due to rivet fatigue damage, so as to reflect the fatigue durability status of the rivet.

2. The fatigue durability testing device for rivet structures according to claim 1, characterized in that, Sealing rings are provided on the opposite end faces of the two sleeves. The sealing rings are used to seal the contact surface between the sleeves and the riveted parts when the ends of the rivets are clamped by the two clamping plates.

3. The fatigue durability testing device for rivet structures according to claim 2, characterized in that, It also includes a U-shaped clamp with a rubber layer on its clamping surface, which is used to clamp the sealing rings of the two covers.

4. The fatigue durability testing device for rivet structures according to claim 1, characterized in that, The support assembly includes a U-shaped guide frame, the end of which is fixedly connected to the side of the ring sleeve, wherein the rotation drive assembly is slidably disposed between the U-shaped areas of the U-shaped guide frame.

5. The fatigue durability testing device for rivet structures according to claim 4, characterized in that, The rotary drive assembly uses a motor, and a connecting rod is arranged radially on the motor. The end of the connecting rod away from the motor is slidably connected to the guide rod of the U-shaped guide frame through a sliding sleeve.

6. The fatigue durability testing device for rivet structures according to claim 5, characterized in that, The linear drive assembly includes: a positioning plate disposed on one side of a U-shaped guide frame, a baffle disposed on the side of the positioning plate facing the motor, an airbag disposed between the baffle and the end of the motor away from the output end, a second air pump disposed on the side of the positioning plate away from the airbag, and the output end of the second air pump communicating with the airbag.

7. The fatigue durability testing device for rivet structures according to claim 6, characterized in that, The positioning plate is connected to the U-shaped guide frame via a positioning ring.

8. The fatigue durability testing device for rivet structures according to claim 1, characterized in that, An installation tube is connected to the ring sleeve. One end of the installation tube is connected to the ring sleeve, and the other end of the installation tube is connected to the first air pump.

9. The fatigue durability testing device for rivet structures according to claim 8, characterized in that, A support rod is connected to the mounting tube, and a display is installed on the support rod. The display is connected to the corresponding pressure detection module via wires.

10. The fatigue durability testing device for rivet structures according to claim 9, characterized in that, The pressure detection module uses a pressure detector. The detection end of the pressure detector is located inside the corresponding housing, and the pressure detector and the display are electrically connected.

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