A test system and test method for a chain hook traction device

Abstract

This invention provides a chain hook traction device testing system and method, relating to the field of traction testing systems. Addressing the problem of existing testing machines' difficulty in real-time and accurate monitoring of chain hooks and traction devices during loading tests, a gantry loading frame is installed on a base. Two sets of actuators are installed side-by-side on the lower part of its crossbeam, corresponding to the chain hook testing station and the traction device testing station, respectively. A self-aligning connection component is provided between the actuator and the test piece. This component, utilizing its structural characteristics, can automatically adjust the force axis during loading, thereby effectively improving or eliminating the lateral shear force on the test piece. Non-contact real-time image data acquisition is performed using visual monitoring devices arranged around the testing stations and transmitted to the control console, achieving continuous and safe monitoring of crack initiation and propagation processes. This effectively meets the EN15566 standard's requirements for real-time, accurate, and safe testing under high dynamic loading environments.

Description

Technical Field

[0001] This invention relates to the field of traction testing systems, and more specifically to a chain hook traction device testing system and testing method. Background Technology

[0002] Chain hooks and traction devices are core connecting components of traditional railway vehicles (especially freight cars). Used together, they achieve flexible connections and traction between vehicles, and their performance directly affects train operation safety. Due to TSI (Technical Specification for Railway System Interoperability), chain hooks and traction devices installed on railway freight cars must strictly meet the requirements of the EN15566 standard. The EN15566 standard not only specifies relevant dimensional interfaces and material properties but also details the stringent procedures for conducting static tensile and dynamic fatigue tests. Particularly in dynamic fatigue testing, it requires applying sinusoidal cyclic loads of specific frequencies and periods to the specimens and rigorously assesses crack initiation and propagation, demanding that the testing system possess high loading accuracy and process monitoring capabilities.

[0003] However, existing general-purpose material testing machines or simple tooling cannot fully meet the specific testing requirements of the EN15566 standard. Traditional testing machines mostly use rigid connection methods, which cannot adapt to the slight posture changes of chain hooks or traction devices during the stress process. This leads to the specimen being subjected to unexpected lateral shear forces, failing to meet the standard's requirement for "pure tensile" stress and seriously affecting the accuracy of fatigue life testing. Existing testing methods mostly rely on contact extensometers or periodic shutdown flaw detection. The former is prone to detachment or displacement under dynamic high-frequency vibration, while the latter is not only inefficient but also poses personnel safety hazards. They cannot achieve real-time capture of crack initiation, making it difficult to meet the testing requirements for real-time and accurate monitoring under high dynamic loading environments. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a chain hook traction device testing system and method that can effectively eliminate lateral shear force and achieve continuous and safe monitoring of crack initiation and propagation processes through non-contact real-time image acquisition, thereby improving testing accuracy and efficiency.

[0005] The first objective of this invention is to provide a chain hook traction device testing system, including a gantry loading frame, a base, and a visual monitoring device; the gantry loading frame is installed on the base, and two sets of actuators are installed side by side on the lower part of the crossbeam of the gantry loading frame, corresponding to the chain hook test station and the traction device test station respectively, for independently or synchronously loading the chain hook and the traction device;

[0006] A self-aligning connection assembly is provided between the actuator and the workpiece under test. The self-aligning connection assembly can adjust the force axis during loading and eliminate the lateral shear force of the workpiece under test. Visual monitoring devices are arranged around the test station to non-contactly acquire image data of the test piece during the loading process in real time and transmit it to the control console, which is used to control the loading process.

[0007] Furthermore, the supporting fixtures for the chain hook testing station include a lower base for the chain hook and an upper pull rod for the chain hook. The two are connected to the chain hook under test by a pin, and the upper pull rod for the chain hook is connected to the actuator through a self-aligning connection assembly.

[0008] Furthermore, the supporting fixtures for the traction device test station include a lower base for the traction device and an upper pull rod for the traction device. The lower base for the traction device is provided with a stop mechanism for limiting the displacement of the traction device under test. The upper pull rod for the traction device is connected to the traction device under test through a pin shaft, and the upper pull rod for the traction device is connected to the actuator through a self-aligning connecting assembly.

[0009] Furthermore, the self-aligning connection assembly includes a spherical bearing or ball joint seat, and a locking nut that mates with it.

[0010] Furthermore, the visual monitoring device is mounted on an independent shock-absorbing support frame, which is inverted U-shaped. A damping vibration isolation component is provided between the bottom and the base. The damping vibration isolation component is used to block the transmission of high-frequency vibrations generated when the actuator is working to the visual monitoring device.

[0011] Furthermore, it also includes a lower tooling installed on the bottom of the workpiece under test. The lower tooling is installed on the base and has a rigid back plate extending from the side, which is within the field of view of the visual monitoring device. The rigid back plate is provided with optical calibration feature marks, which are used by the visual monitoring device to establish a follow-up coordinate system and perform differential displacement calculation.

[0012] Furthermore, the gantry loading frame includes two legs and a crossbeam. The bottom of the legs is fixed to both ends of the base to form a frame structure. A hydraulic system is installed on the base, and the actuator is an electro-hydraulic servo actuator. The output end of the hydraulic system is connected to the electro-hydraulic servo actuator. The hydraulic system receives and executes control commands from the control console.

[0013] Furthermore, the console is integrated with the base and equipped with a human-machine interface. The console is used to drive the actuator to perform static tensile loading or sinusoidal dynamic fatigue loading.

[0014] A second objective of this invention is to provide a test method for a chain hook traction device test system, utilizing the chain hook traction device test system of the first objective, comprising: The two sets of actuators under the crossbeam of the gantry loading frame are controlled by the console to perform independent or synchronous loading on the test pieces at the chain hook test station and the traction device test station, respectively. During the loading process, the force axis is automatically adjusted by the self-aligning connection component set between the actuator and the workpiece, eliminating the lateral shear force on the workpiece. Using visual monitoring devices arranged around the test station, non-contact real-time image data of the test piece during the loading process is acquired, and the acquired image data is transmitted to the control console.

[0015] Furthermore, the independent loading or synchronous loading includes two modes: One is a static tensile loading mode, in which the actuator is controlled to apply a gradually increasing tensile force to the test piece until the minimum breaking load value specified in the standard is reached or until the test piece breaks. Another mode is dynamic fatigue loading, which controls the actuator to apply a sinusoidal cyclic load to the test piece, sets the loading frequency, and continuously loads according to the preset number of cycles and load peak and valley values.

[0016] Compared with the prior art, the advantages and positive effects of this invention are: To address the challenge of real-time and accurate monitoring of chain hooks and traction devices during loading tests in existing testing machines, a gantry loading frame is installed on a base. Two sets of actuators are mounted side-by-side on the lower part of its crossbeam, corresponding to the chain hook test station and the traction device test station, respectively. This allows for independent or synchronous loading of the chain hook and traction device. A self-aligning connection assembly is installed between the actuator and the test piece. This assembly, utilizing its structural characteristics, automatically adjusts the force axis during loading, effectively improving or eliminating lateral shear forces on the test piece and ensuring the loading force line is closer to the "pure tension" state required by the standard. Simultaneously, non-contact real-time image data acquisition and transmission to the control console are achieved using visual monitoring devices arranged around the test stations. This not only avoids the risk of sensor detachment or displacement, enabling continuous and safe monitoring of crack initiation and propagation, but also significantly improves testing efficiency through parallel operation of the two stations. This effectively meets the EN15566 standard's requirements for real-time, accurate, and safe testing under high dynamic loading environments.

[0017] To address the issue of blurred image acquisition caused by slight vibrations of the base during high-frequency dynamic loading, a visual monitoring device mounted on an independent vibration-damping support frame was adopted. Through the combination of an inverted U-shaped structure and damping vibration isolation components, the transmission of high-frequency mechanical waves generated during actuator operation to the visual monitoring device was effectively blocked or attenuated along the physical path. This provided a relatively stable imaging environment for non-contact measurement, improving the clarity of image data and the reliability of monitoring in dynamic fatigue tests. Furthermore, a rigid backplate with optical calibration feature marks was installed on the side of the lower fixture. Utilizing the synchronous movement of the rigid backplate and the workpiece under test, a tracking coordinate system was established. This allowed the visual monitoring device to use a differential algorithm to subtract background displacement noise caused by base vibration, calculating only the actual deformation of the workpiece relative to the fixture. This effectively improved the measurement accuracy of micro-crack propagation and permanent deformation in complex industrial environments.

[0018] The self-aligning connection assembly uses a spherical bearing or ball joint seat with a locking nut. Utilizing the free rotation characteristics of the spherical surface, it can compensate for installation errors and slight deflection of the specimen during loading. This not only ensures that the loading force line always tends to pass through the geometric center of the specimen, meeting the stringent requirements of EN15566 for the stress state, but also effectively reduces the risk of actuator seal wear caused by off-center loading, extending the service life of the equipment.

[0019] By integrating the console with the base and incorporating a human-machine interface, centralized intelligent management of the testing process is achieved. This allows operators to easily set complex loading spectra such as static tensile or sinusoidal dynamic fatigue. The system can execute control commands and provide real-time feedback on the status, thereby effectively reducing the difficulty of operation and improving the level of automation and work efficiency of the test. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0021] Figure 1 This is a schematic diagram of the structure of a test system for a chain hook traction device in one or more embodiments of the present invention.

[0022] Figure 2 This is a schematic diagram of the chain hook installation in one or more embodiments of the present invention.

[0023] Figure 3 This is a schematic diagram of the installation of the traction device in one or more embodiments of the present invention.

[0024] Figure 4 This is a schematic diagram of the dynamic fatigue test load spectrum in one or more embodiments of the present invention.

[0025] Figure 5 This is a schematic diagram of the time history curve of dynamic fatigue test in one or more embodiments of the present invention.

[0026] Among them, 1. First load peak value; 2. Second load peak value; 3. First load valley value; 4. Loading frequency; 100. Gantry loading frame; 101. Base; 110. Outrigger; 130. Actuator; 200. Hydraulic system; 201. Oil pump motor; 202. High and low pressure oil circuit; 210. Oil distributor; 300. Servo control console; 400. Visual monitoring device; 500. Chain hook loading assembly; 501. Chain hook; 510. Chain hook lower base; 520. Chain hook upper pull rod; 600. Traction device loading assembly; 601. Traction device; 610. Traction device lower base; 620. Traction device upper pull rod. Detailed Implementation

[0027] Example 1 In a typical embodiment of the present invention, such as Figures 1-5 As shown, a test system for a chain hook traction device is presented.

[0028] Existing general-purpose material testing machines or simple fixtures cannot adapt to minute changes in the posture of the test piece when performing loading tests on the chain hook 501 and traction device 601, resulting in the test piece being subjected to unexpected lateral shear forces, affecting the accuracy of fatigue life testing. Detection methods mostly rely on contact extensometers or periodic stop-and-inspection, which cannot achieve real-time capture of crack initiation, making it difficult to meet the testing requirements for real-time and accurate monitoring under high-dynamic loading environments. Therefore, this embodiment provides a chain hook traction device testing system. Two sets of actuators 130 are installed side-by-side on the lower part of the gantry loading frame 100 crossbeam, corresponding to the test positions of the chain hook 501 and traction device 601 respectively. A self-aligning connection component is set between the actuator 130 and the test piece to eliminate lateral shear forces. Simultaneously, a visual monitoring device 400 achieves non-contact real-time image acquisition, effectively eliminating lateral shear forces. Through non-contact real-time image acquisition, continuous and safe monitoring of crack initiation and propagation processes is achieved, offering advantages in improving testing accuracy and efficiency.

[0029] like Figures 1-5 The chain hook traction device test system includes a gantry loading frame 100, a base 101, and a visual monitoring device 400. The gantry loading frame 100 is mounted on the base 101. Two sets of actuators 130 are installed side by side on the lower part of the crossbeam of the gantry loading frame 100, corresponding to the test station of the chain hook 501 and the test station of the traction device 601, respectively, for independently or synchronously loading the chain hook 501 and the traction device 601.

[0030] A self-aligning connection assembly is provided between the actuator 130 and the test piece. This self-aligning connection assembly can adjust the force axis during loading and eliminate the lateral shear force of the test piece. The visual monitoring device 400 is arranged around the test station to collect image data of the test piece in real time during loading in a non-contact manner and transmit it to the control console 300, which is used to control the loading process.

[0031] The gantry loading frame 100 can be constructed from welded or bolted metal profiles to form a stable frame structure for supporting and positioning the loading components. The base 101 can be made of heavy steel plates or concrete to provide stable support for the entire testing system. The visual monitoring device 400 can be an industrial camera or a high-speed camera to capture image information during the testing process.

[0032] The bottom of the legs 110 of the gantry loading frame 100 can be fixed to the reserved holes of the base 101 by anchor bolts, or connected to the base 101 by welding, to ensure that the loading frame remains in a fixed position during the test.

[0033] Two sets of actuators 130 are installed side-by-side on the lower part of the crossbeam of the gantry loading frame 100. The two sets of actuators 130 correspond to the test station of the chain hook 501 and the test station of the traction device 601, respectively. The actuators 130 can be mechanical screw actuators 130, pneumatic actuators 130, or electro-hydraulic servo actuators 130, driven by a motor, pneumatic pressure, or hydraulic pressure to apply tensile force to the test piece. The test station of the chain hook 501 and the test station of the traction device 601 can be equipped with independent clamps or connectors to fix the chain hook 501 and the traction device 601 to be tested. By controlling the two sets of actuators 130, independent loading of the chain hook 501 and the traction device 601 can be achieved, i.e., applying force to the test piece at only one station, or synchronous loading can be achieved, i.e., applying the same or different forces to the test pieces at both stations simultaneously.

[0034] The function of a self-aligning connection assembly is to automatically adjust the force axis during loading to eliminate lateral shear forces that the test piece may experience. For example, a self-aligning connection assembly can be composed of a universal joint or a flexible connector, which allows the connector to deflect within a certain range, thereby ensuring that the loading force line remains aligned with the axis of the test piece.

[0035] The visual monitoring device 400 is used to perform non-contact real-time image data acquisition on the test piece during the loading process, realizing AI image recognition measurement. For example, the visual monitoring device 400 can be installed on an independent bracket next to the test station, aiming the lens at the test piece and continuously capturing images at a preset frame rate. The acquired image data is then transmitted to the control console 300.

[0036] The control console 300 can be an industrial computer running specialized control software. Operators input loading parameters, such as loading force, loading frequency, or number of cycles, through the control console 300. The control console 300 sends control signals to the actuator 130 according to these instructions and receives image data from the visual monitoring device 400, thereby enabling monitoring and management of the entire test process.

[0037] The control console 300 can control the actuator 130 individually or in conjunction with other actuators through the human-machine interface, drive the actuator 130 to perform static tension or sinusoidal dynamic fatigue loading, and issue instructions such as specimen crack warning and automatic emergency stop based on the data fed back by the visual monitoring device 400.

[0038] The chain hook traction device test system of this embodiment, through the configuration of the gantry loading frame 100, dual actuators 130, and self-aligning connection components, can independently or synchronously apply pure tensile loading to the chain hook 501 and the traction device 601, effectively avoiding the lateral shear force caused by traditional rigid connections and improving the accuracy of fatigue life testing. Simultaneously, non-contact real-time image data acquisition is performed using visual monitoring devices 400 arranged around the test station, and centralized control is achieved by the control console 300. This overcomes the problems of easy detachment, low efficiency, and safety hazards associated with contact detection methods, realizing continuous and accurate monitoring of crack initiation and propagation processes, and meeting the real-time, accurate, and safe testing requirements under high dynamic loading environments.

[0039] In this embodiment, as Figure 2 As shown, a matching fixture for the chain hook 501 test station is proposed, which includes a lower base 510 for the chain hook and an upper pull rod 520 for the chain hook. The chain hook 501 test station is a dedicated area in the testing system for performing load tests on the chain hook 501. It is equipped with specific installation interfaces and spatial layouts to accommodate the installation requirements of chain hooks 501 of different sizes and types, and to ensure stability and safety during the loading process.

[0040] The matching fixture for the chain hook 501 test station refers to the chain hook loading assembly 500 specially designed to achieve effective fixation and loading of the chain hook 501 at the test station. It can reliably connect the irregularly shaped chain hook 501 under test to the standardized actuator 130 interface, while ensuring the accurate transmission of loading force.

[0041] The lower base 510 of the chain hook, as part of the chain hook 501 loading assembly, primarily functions to provide stable bottom support and a fixing point for the chain hook 501 under test. The lower base 510 typically possesses sufficient strength and rigidity to withstand the tensile force transmitted by the chain hook 501 during loading and to prevent unnecessary displacement or rotation of the chain hook 501 during loading. The lower base 510 may include grooves, pin holes, or other fixing structures for positioning the lower part of the chain hook 501.

[0042] The chain hook upper pull rod 520, as another part of the matching tooling, connects the upper part of the chain hook 501 to the actuator 130. The chain hook upper pull rod 520 can withstand high tensile loads and has a connection interface that matches the upper part of the chain hook 501 and the self-aligning connection assembly. The length and shape of the chain hook upper pull rod 520 can be adjusted according to the geometry of the chain hook 501 and the layout of the test system.

[0043] The lower base 510 of the chain hook and the upper pull rod 520 of the chain hook are connected to the chain hook 501 under test by a pin, realizing a detachable connection between the chain hook 501 and the lower base 510 and the upper pull rod 520 of the chain hook. The pin is usually made of high-strength steel and fixes the chain hook 501 by passing through the hole in the chain hook 501 and the corresponding hole on the tooling, while allowing a certain degree of relative rotation to accommodate minor deformations during the loading process.

[0044] The self-aligning connection assembly automatically adjusts the force axis, eliminating lateral shear forces on the test piece. This ensures the connection between the chain hook pull rod 520 and the actuator 130 can accommodate minor misalignments that may occur during loading, thus guaranteeing that the loading force line always passes through the central axis of the chain hook 501 and avoiding off-center loading. A specialized fixture is provided for the chain hook 501 testing station, which not only improves the accuracy of loading and the reliability of test results but also prevents premature damage to the actuator 130 or the test piece due to off-center loading, thereby extending the equipment's service life and ensuring the validity of the test data.

[0045] like Figure 3 As shown, the supporting fixture for the test station of the traction device 601 is the loading assembly of the traction device 601, specifically including the lower base 610 of the traction device and the upper pull rod 620 of the traction device. The traction device 601 under test is securely installed on the test system, and an interface for connection with the actuator 130 is provided to ensure effective transmission of loading force and stability of the test process.

[0046] The lower base 610 of the traction device supports the bottom of the traction device 601 under test and fixes it to the base 101. Its specific structure is adapted to the geometry and dimensions of the traction device 601 under test to provide a stable mounting platform. For example, it can be designed with adjustable clamps or positioning slots to accommodate different models of traction devices 601. The lower base 610 of the traction device is equipped with a stop mechanism to limit the displacement of the traction device 601 under test, particularly limiting lateral or rotational displacement, thereby ensuring that the loading force line always acts at the expected position and preventing the tested part from undergoing undesirable movement due to uneven force. The stop mechanism can take various forms, such as a limit block fixed to the base, an adjustable clamping device, or a groove structure matching the shape of the tested part, effectively constraining the degree of freedom of the tested part without affecting normal loading.

[0047] The upper pull rod 620 of the traction device serves as an intermediate component connecting the tested traction device 601 and the actuator 130. One end of the rod is connected to the tested traction device 601 via a pin, and the other end is connected to the actuator 130 via a self-aligning connecting assembly. The pin ensures that the load force can be transmitted to the tested traction device 601 and allows for minor angular adjustments to the tested component during loading to accommodate the adjustment of the force axis of the self-aligning connecting assembly. The upper pull rod 620 of the traction device needs to possess sufficient strength and rigidity to withstand the tensile force generated during loading and ensure effective force transmission. Connecting to the actuator 130 via the self-aligning connecting assembly automatically adjusts the force axis, eliminating lateral shear forces that may be generated during loading and ensuring that the loading force line is aligned with the axis of the tested traction device 601.

[0048] Specifically, in this embodiment, the self-aligning connection assembly includes a spherical bearing or ball joint seat and a locking nut that mates with it. The self-aligning connection assembly can provide a variable-angle connection to accommodate dynamic changes in the force axis during loading.

[0049] Among them, spherical plain bearings are bearings that can withstand large radial and axial loads and allow oscillation and rotation within a certain angle range. They consist of an inner ring with a spherical outer surface and an outer ring with a corresponding spherical inner surface. Through this spherical fit, spherical plain bearings can compensate for installation errors and axial misalignment, ensuring smooth force transmission.

[0050] A ball joint, also known as a spherical connector, provides multi-directional rotational freedom. It consists of a spherical component and a mating seat. The spherical component can rotate freely within the seat, allowing for angle adjustment between the connecting parts. When subjected to tensile or compressive loads, the ball joint automatically adjusts its posture through its spherical structure, ensuring that the force line always tends to pass through the geometric center of the connecting parts.

[0051] Lock nuts are used with spherical plain bearings or ball joints to securely lock the connection in place after it has been adjusted, preventing loosening during testing due to vibration or load variations. Lock nuts can also be selected with options such as those featuring nylon inserts, modified threads, or double nuts to provide additional friction or mechanical locking, ensuring the reliability and stability of the connection.

[0052] During loading, regardless of initial installation errors or slight deflection of the test piece under load, the self-aligning connection assembly can automatically and in real time adjust the force axis to ensure that the loading force line always tends to pass through the geometric center of the test piece. This improves the purity of the loading force line, making it closer to the "pure tension" state required by the standard, thereby ensuring the accuracy and reliability of the test data. It also effectively avoids local stress concentration and abnormal wear of the actuator 130 seal caused by off-center loading, thus extending the service life of the actuator 130, reducing maintenance costs, and improving the operational stability of the entire test system.

[0053] During actual dynamic loading tests, the high-frequency vibrations generated by the actuator 130 during operation may be transmitted through the base 101, interfering with the image acquisition of the visual monitoring device 400 and affecting the clarity and accuracy of the monitoring data. To address this, in this embodiment, the visual monitoring device 400 is mounted on an independent vibration-damping support frame. The independent vibration-damping support frame is inverted U-shaped, and a damping vibration isolation component is provided between its bottom and the base 101. This damping vibration isolation component is used to block the transmission of high-frequency vibrations generated by the actuator 130 during operation to the visual monitoring device 400.

[0054] The independent vibration damping support frame effectively supports the visual monitoring device 400, enabling it to be precisely aligned with the test station and maintained within a preset field of view. The overall structure of the independent vibration damping support frame is designed in an inverted U-shape, providing excellent mechanical stability and effectively resisting external disturbances. The damping and vibration isolation assembly is located between the bottom of the independent vibration damping support frame and the base 101. This damping and vibration isolation assembly can take various forms, such as being composed of high-damping rubber, composite materials, air springs, or spring dampers, providing a flexible connection to physically isolate the independent vibration damping support frame from the base 101, thereby preventing or significantly attenuating vibrations transmitted from the base 101. The damping vibration isolation component uses its internal damping material or structure to convert the high-frequency mechanical vibration energy generated by the actuator 130 during loading into heat energy or other forms of energy dissipation. This effectively prevents vibration from being transmitted through the base 101 to the independent vibration damping support frame and the visual monitoring device 400 installed on it, improving the clarity of image acquisition and the accuracy of monitoring data, and ensuring continuous and safe monitoring of the crack initiation and propagation process of the tested component.

[0055] In this embodiment, for the lower tooling installed at the bottom of the test piece, such as the lower base 510 of the chain hook and the lower base 610 of the traction device installed on the base 101, a rigid back plate is provided on its side within the field of view of the visual monitoring device 400. The rigid back plate is provided with optical calibration feature marks for the visual monitoring device 400 to establish a follow-up coordinate system and perform differential displacement calculation.

[0056] The rigid backplate is a structure extending from the side of the lower tooling. It does not undergo perceptible deformation during loading tests. The rigid backplate is positioned within the field of view of the visual monitoring device 400, serving as a reference plane for visual monitoring. Optical calibration feature marks are specific patterns or dot matrices pre-set on the rigid backplate, such as high-contrast circular dots, crosshairs, or coded marks. These marks have clear geometric positions and are easily identifiable, facilitating image processing and feature point recognition by the visual monitoring device 400.

[0057] The visual monitoring device 400 identifies and tracks optical calibration feature marks on the rigid backplate, determines the position of these marks in the image in real time, and establishes a local coordinate system that moves synchronously with the rigid backplate based on this. This coordinate system can move synchronously with the minute displacements of the base 101 and the lower tooling. After establishing the follow-up coordinate system, the visual monitoring device 400 can measure the displacement of points of interest (e.g., crack tips or deformation areas) on the test piece relative to this follow-up coordinate system. By comparing the displacement of these points with the displacement of the follow-up coordinate system itself, the overall displacement of the base 101 and the lower tooling can be effectively subtracted, thereby accurately calculating the true deformation of the test piece.

[0058] In this embodiment, under complex dynamic loading conditions where the base 101 experiences slight vibrations or displacements, the visual monitoring device 400 can establish a follow-up coordinate system through optical calibration feature marks on the rigid back plate. This allows for real-time tracking and compensation of the overall movement of the base 101, freeing the displacement measurement of the test piece from background noise in a fixed coordinate system. Based on this, differential displacement calculation effectively filters out background displacements caused by the vibration of the base 101, thereby separating the true deformation of the test piece. This improves the accuracy and reliability of measuring micro-crack initiation, propagation, and permanent deformation, enabling the testing system to more accurately evaluate the fatigue performance and damage evolution process of the test piece, meeting the requirements of high-precision testing.

[0059] Specifically, such as Figure 1As shown, the gantry loading frame 100 includes two legs 110 and a crossbeam. The bottom of the legs 110 is fixed to both ends of the base 101 to form a frame structure. A hydraulic system 200 is installed on the base 101. The actuator 130 is an electro-hydraulic servo actuator 130. The output end of the hydraulic system 200 is connected to the electro-hydraulic servo actuator 130. The hydraulic system 200 receives and executes the control commands from the control console 300.

[0060] Specifically, the legs 110 and crossbeam of the gantry loading frame 100 are both box-shaped structures welded from plate. The legs 110 are fixed to both ends of the crossbeam with top bolts, and the bottom is fixed to the base 101 to form a stable frame structure. Two electro-hydraulic servo actuators 130 are installed and fixed at the lower part of the crossbeam. The frame structure can effectively resist the reaction force generated during loading, provide solid support for the actuators 130, and ensure the accurate transmission of loading force, avoiding structural deformation from affecting the test results.

[0061] The hydraulic system 200, mounted on the base 101, is the core component providing power to the actuator 130. The hydraulic system 200 includes an oil pump motor 201, an oil reservoir, high and low pressure oil circuits 202, and a distributor 210. The distributor 210 connects to the electro-hydraulic servo actuator 130, converting mechanical energy into hydraulic energy, which drives the actuator 130 through hydraulic oil pressure. The hydraulic system 200 provides a wide range of force and speed control, making it particularly suitable for fatigue tests requiring high loads, high-frequency response, and precise control. Mounting the hydraulic system 200 on the base 101 allows for a compact layout and reduces energy transmission losses.

[0062] Actuator 130 is configured as an electro-hydraulic servo actuator 130, combining the high-power output capability of hydraulic system 200 with the high-precision control capability of electronic servo system. It can precisely control the flow and pressure of hydraulic oil through servo valves, thereby achieving precise control of the piston rod position, speed, and force of actuator 130. Compared to pure hydraulic actuator 130 or electric actuator 130, electro-hydraulic servo actuator 130 has advantages such as fast response speed, high control accuracy, large output force, and good rigidity, making it particularly suitable for static tensile, dynamic fatigue, and complex waveform loading tests. It typically integrates displacement and force sensors internally for real-time feedback of the actuator 130's status, enabling closed-loop control of the system. The output end of hydraulic system 200, i.e., the high-pressure hydraulic oil line, is connected to the inlet of electro-hydraulic servo actuator 130 through appropriate connectors and pipes, ensuring that the powerful force provided by hydraulic system 200 can be efficiently and stably transmitted to actuator 130, enabling it to precisely execute actions according to the preset loading program. Furthermore, the hydraulic system 200 does not operate independently; rather, it serves as a controlled unit within the entire testing system, communicating with the control console 300 via an electrical interface and receiving commands from it. These commands include starting / stopping the hydraulic pump, adjusting system pressure, and controlling the opening of servo valves. The control unit within the hydraulic system 200 parses these commands and drives the corresponding hydraulic components to perform the actions.

[0063] like Figure 1 As shown, the control console 300 is integrated with the base 101 and equipped with a human-machine interface (HMI). The control console 300 is used to drive the actuator 130 to perform static tensile loading or sinusoidal dynamic fatigue loading. The HMI serves as the hardware and software interface for operators to exchange information and input commands with the system. It typically includes a touchscreen display, physical buttons, knobs, indicator lights, etc. The HMI software is a graphical user interface (GUI), providing intuitive menus, parameter input boxes, real-time data display areas, status indicators, etc. The HMI supports setting test parameters (such as loading mode, load peak and valley values, frequency, number of cycles, etc.), monitoring the test process (such as real-time load, displacement, image data preview, etc.), fault diagnosis, and data management functions to ensure ease of operation and intuitiveness. For static tensile loading, the control software instructs the actuator 130 to gradually increase the tensile force at a set rate until the target load is reached or the test piece breaks. For sinusoidal dynamic fatigue loading, the control software generates periodic sinusoidal command signals, which precisely control the flow and pressure of hydraulic oil through the servo valve, so that the actuator 130 outputs a sinusoidal load that conforms to the set frequency, peak and valley values ​​and number of cycles.

[0064] Example 2 In another typical embodiment of the present invention, such as Figures 1-5As shown, a test method for a chain hook traction device test system is provided, utilizing the chain hook traction device test system as described in Example 1, including the following steps: The two sets of actuators 130 under the crossbeam of the gantry loading frame 100 are controlled by the console 300 to perform independent or synchronous loading on the test piece at the chain hook 501 test station and the traction device 601 test station, respectively. During the loading process, the force axis is automatically adjusted by the self-aligning connection component set between the actuator 130 and the workpiece, thereby eliminating the lateral shear force on the workpiece. Using a vision monitoring device 400 arranged around the test station, non-contact real-time image data is acquired of the test piece during the loading process, and the acquired image data is transmitted to the control console 300.

[0065] In addition, independent loading or synchronous loading includes two modes: One of the modes is the static tensile loading mode. In this mode, the control console 300 controls the actuator 130 to apply a gradually increasing tensile force to the test piece until the minimum breaking load value specified by the standard is reached or until the test piece breaks.

[0066] The static tensile loading mode is mainly used to determine the basic mechanical properties of materials, such as yield strength, tensile strength, elongation after fracture, and reduction of area, as well as to verify the load-bearing capacity and failure mode of the test piece under ultimate static load. Specifically, the control console 300 sends instructions to the electro-hydraulic servo actuator 130 through a preset loading program, causing the actuator 130 to apply tensile force to the test piece at a constant rate or a preset loading curve. During the loading process, the system monitors the load and displacement data in real time. When the load reaches the preset minimum breaking load value, the test can be stopped; or, loading can continue until the test piece undergoes macroscopic fracture to obtain its ultimate load-bearing capacity.

[0067] Another mode is the dynamic fatigue loading mode. In this mode, the control console 300 controls the actuator 130 to apply a sinusoidal cyclic load to the test piece, sets the loading frequency to 4, and continuously loads according to the preset number of cycles and load peak and valley values.

[0068] The dynamic fatigue loading mode can simulate the cyclic loads experienced by the test piece during actual operation to evaluate its fatigue life and fatigue strength. The control console 300 generates a sine wave signal through its built-in waveform generator, driving the electro-hydraulic servo actuator 130 to repeatedly load the test piece according to a set frequency (e.g., several to tens of cycles per second) and load peak and trough values ​​(i.e., maximum tensile load and minimum tensile or compressive load). The test continues until the preset number of cycles is reached, or the test piece fails due to fatigue. By adjusting the loading frequency, load ratio (R value), and load amplitude, different working environments and stress states can be simulated.

[0069] Specifically, the test methods for the chain hook traction device test system include the following tests.

[0070] 1. Static tensile-semi-minimum fracture load test: S1: Select the minimum breaking load value and initial load value corresponding to the specifications of the tested chain hook 501 and traction device 601 according to the EN15566 standard.

[0071] S2: Install the test chain hook 501 and traction device 601 to the corresponding positions.

[0072] S3: Control the servo control console 300 to apply a tensile load, so that it reaches and remains at the initial load value.

[0073] S4: AI image recognition measurement is achieved through the visual monitoring device 400. A coordinate system is established by identifying the feature marks on the rigid backplate, and the relevant parameters that need to be measured are recorded.

[0074] S5: Control the servo console 300 to gradually increase the tensile load until it reaches or exceeds half of the minimum breaking load value as little as possible, and then hold it for at least 1 minute.

[0075] S6: Control the servo control console 300 to gradually reduce the tensile load, so that it reaches and remains at the initial load value.

[0076] S7: AI image recognition measurement is achieved through the visual monitoring device 400, and the relevant parameters that need to be measured are recorded again.

[0077] S8: Using the data recorded by the measurements in S4 and S7 above, the permanent deformation is calculated by differential calculation, and the semi-minimum fracture load test results are obtained.

[0078] 2. Static tensile test - minimum breaking load test: S1: This test continues after step S7 of the semi-minimum fracture load test.

[0079] S2: The servo control console 300 gradually increases the tensile load to reach or exceed the minimum breaking load value as little as possible (the chain hook 501 is applied at 95% of the minimum breaking load value), and then holds it for at least 3 minutes. During this period, the visual monitoring device 400 works stably on the independent shock-absorbing support frame to realize AI image recognition measurement, monitor the status of the test chain hook 501 and traction device 601 in real time, and monitor whether cracks are initiating.

[0080] S3: Control the servo control console 300 to unload the tensile load and complete the minimum breaking load test.

[0081] 3. Static tensile test - maximum breaking load test: S1: This test is performed only on chain hook 501 and continues after step S3 of the minimum breaking load test.

[0082] S2, control the servo control console 300 to gradually increase the tensile load until the chain hook 501 breaks at the preset weakest point. Record the maximum value of the tensile load before the breakage through the servo control console 300, and the visual monitoring device 400 records the image at the moment of breakage to obtain the test result of the maximum breakage load.

[0083] 4. Dynamic fatigue testing, such as Figure 5 As shown: S1: The dynamic fatigue test should be conducted with a new chain hook 501 and traction device 601, and the installation method is the same as that for the static tensile test. Before starting the dynamic fatigue test, the test specimen should be preloaded and subjected to surface flaw detection at least once.

[0084] S2: Using the servo console 300 human-machine interface, sinusoidal loading spectra suitable for chain hook 501 and traction device 601 are programmed separately in a load control manner. The peak and trough values ​​of the load, the cycle mode, and the number of cycles shall comply with the requirements of EN15566 standard. Figure 4 The first load peak value 1, the second load peak value 2, and the first load valley value 3 shown, and the loading frequency 4 should not exceed 4Hz.

[0085] S3: The servo control console 300 and electro-hydraulic servo actuator 130 apply sinusoidal tensile cyclic loading to the chain hook 501 and traction device 601 according to the programmed load spectrum until the total number of cycles meets the standard requirements. During this process, the damping vibration isolation component blocks high-frequency vibration, and the visual monitoring device 400 continuously acquires high-definition images. In conjunction with the follow-up coordinate system of the rigid backplate, the crack propagation is monitored in real time.

[0086] S4. Perform flaw detection on the chain hook 501 and traction device 601 after completing the tensile cycle; no cracks should be found. Then perform a residual strength test; during the residual strength test, the tested chain hook 501 and traction device 601 should not break.

[0087] S5. The three test chain hooks 501 and traction devices 601 used for dynamic fatigue testing should all meet the residual strength test to obtain the dynamic fatigue test results.

[0088] Understandably, taking a 1MN chain hook 501 and traction device 601 with a 30-year service life dynamic fatigue test as an example, the chain hook 501 and traction device 601, after preloading and surface flaw detection, are installed in the aforementioned corresponding positions. According to the standard requirements, the dynamic fatigue test's "S1" load cycle should be periodically alternated with the "S2" load cycle. The total number of "S1" cycles is 1,500,000, and the total number of "S2" cycles is 2,150. The number of alternating cycles of the two steps can form one block, and the total number of test cycles is divided into at least 40 blocks. The load spectrum is programmed through the human-machine interface of the servo console 300. The load spectrum specifies that each block consists of 30,000 "S1" cycles and 43 "S2" cycles, with a total of 50 cycles executed in each block. The electro-hydraulic servo actuator 130 is controlled by the console 300 to execute the load spectrum, reaching the total number of test cycles and completing the dynamic fatigue test.

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. 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. A chain and hook traction device testing system, characterized by, The gantry loading frame is installed on the base, and two sets of actuators are installed side by side at the lower part of the cross beam of the gantry loading frame, corresponding to the chain hook test station and the traction device test station respectively, for independent or synchronous loading of the chain hook and the traction device. Self-aligning connecting assemblies are arranged between the actuators and the measured parts, and the self-aligning connecting assemblies can adjust the stress axis during loading to eliminate the lateral shear force of the measured parts. The visual monitoring device is arranged around the test station, and is used for non-contact real-time acquisition of image data of the measured part during loading and transmission to the console.

2. The chain and hook drawstring test system of claim 1, wherein, The supporting tool of the chain hook test station includes a lower base and an upper pull rod, and the measured chain hook is connected through a pin shaft.

3. The chain and hook draw test system of claim 1 or 2, wherein, The supporting tool of the traction device test station includes a lower base and an upper pull rod, and the measured traction device is connected through a pin shaft.

4. The chain and hook drawstring test system of claim 3, wherein, The self-aligning connecting assembly includes a joint bearing or a ball hinge seat, and a locking nut matched therewith.

5. The chain and hook drawstring test system of claim 1, wherein, The visual monitoring device is installed on an independent damping support frame, the independent damping support frame is in an inverted U shape, and a damping vibration isolation assembly is arranged between the bottom and the base.

6. The chain and hook drawstring test system of claim 5, wherein, The lower tool installed at the bottom of the measured part is installed on the base, and a rigid back plate within the visual monitoring device field of view is arranged on the side surface, and an optical calibration feature mark is arranged on the rigid back plate, which is used for establishing a servo coordinate system and performing differential displacement calculation.

7. The chain and hook drawstring test system of claim 1, wherein, The gantry loading frame includes two legs and a cross beam, the legs are fixed at the two ends of the base to form a frame structure, a hydraulic system is installed on the base, the actuator is an electro-hydraulic servo actuator, the output end of the hydraulic system is connected to the electro-hydraulic servo actuator, and the hydraulic system receives control instructions from the console and executes them.

8. The chain and hook draw test system of claim 1 or 7, wherein, The console is integrally installed with the base and is provided with a human-computer interaction interface, and the console is used for driving the actuator to perform static tensile loading or sinusoidal dynamic fatigue loading.

9. A test method of a chain and hook towing device test system using the chain and hook towing device test system according to any one of claims 1 to 8, characterized by, The console controls the two sets of actuators at the lower part of the cross beam of the gantry loading frame, and independently loads or synchronously loads the measured parts of the chain hook test station and the traction device test station; During loading, the self-aligning connecting assembly arranged between the actuator and the measured part automatically adjusts the stress axis to eliminate the lateral shear force of the measured part; The visual monitoring device arranged around the test station is used for non-contact real-time image data acquisition of the measured part during loading, and the acquired image data is transmitted to the console. The independent loading or synchronous loading includes two modes:

10. The test method of the test system for chain and hook towing apparatuses according to claim 9, characterized in that, One is a static tensile loading mode, in which the actuator applies an increasing tensile force to the measured part until the minimum breaking load value specified by the standard is reached or the measured part breaks; ​ Another is dynamic fatigue loading mode, control actuator to the measured piece to apply sinusoidal wave cycle load, set the loading frequency, and according to the preset cycle and load peak to valley value of continuous loading.

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