Testing device and testing method for loading three-dimensional conical fatigue load

Abstract

The invention provides a test device and a test method for loading a three-dimensional conical fatigue load. The device comprises a bearing beam frame assembly, a sliding rod supporting assembly, a displacement coordination loading system, an axial force loading system, a stay cable simulation test piece and a stay cable simulation fixing tool, by analyzing the working states of flexible connecting structural members such as inhaul cables and mooring ropes, the invention provides a new fatigue loading form, and the loaded axial force is always in the axial direction of the structural members and can rotate in the space; the loading form can truly reflect the'pull-pull 'fatigue life of the structural member in a specific working environment, and is used for guiding maintenance and repair of key equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible connection fatigue testing, and particularly relates to a test device and a test method for three-dimensional conical fatigue load loading. Background Art

[0002] During the use of products and equipment such as sounding balloons, airships, and hot air balloons, the structure is usually connected and fixed by cables or mooring ropes. When this flexible connection is affected by wind loads in different directions, it will shake to a certain extent. This phenomenon will cause the fixing points of the device to be subjected to tensile forces from all directions. In addition, during various production activities, such as the hoisting of lifting equipment and the handling of heavy objects, the hook position will also be subjected to similar external forces. The components bearing this load are often key load-bearing components in the device. Therefore, it is very necessary to analyze the fatigue or wear life of each key component in the connection device under the above complex stress conditions.

[0003] By analyzing the force characteristics of flexible connection devices such as cables during use, the force direction is always along the cable axis. When the connected equipment is interfered by external forces in non-axis directions, the magnitude of the force along the cable axis will change, and the force direction of the device fixing point will also deflect at an angle under the influence of complex external forces. Therefore, when analyzing the fatigue life of the connection device, not only the tensile force factor along the axis direction needs to be considered, but also the influence of its continuously changing deflection angle on the structural life needs to be considered. Combining the above two factors and performing a certain amount of idealization processing on the force model, a three-dimensional conical fatigue load with a circular or elliptical bottom surface can be obtained.

[0004] Since the fixing methods of structures such as cables and mooring ropes generally use hinge supports, their opening and closing angles are relatively large. It is difficult to use existing three-axis fatigue testing machines to analyze the fatigue life of large deformations. Therefore, it is necessary to design a test device that can not only meet the requirements of large deformations but also simulate the force application mode of the cable structure as much as possible to analyze its fatigue life, so as to guide the maintenance and repair of key equipment. Summary of the Invention

[0005] Object of the Invention: The present invention provides a test device and a test method for three-dimensional conical fatigue load loading, aiming to solve the fatigue life and wear problems of key components of structural members such as cables and mooring ropes under the influence of external forces in multiple directions.

[0006] The present invention provides a test device for three-dimensional conical fatigue load loading, including a load-bearing beam frame assembly, a slide bar support assembly, a displacement coordination loading system, an axial force loading system, a cable simulation test piece, and a cable simulation fixing tooling;

[0007] Among them, the load-bearing beam frame assembly is used to support and fix the slide bar support assembly, the displacement coordination loading system, and the axial force loading system; the slide bar support assembly is used to ensure that the loading device moves along the X-Y plane without tipping over; the displacement coordination loading system is used to control the conical opening angle and at the same time play a role in supporting the loading device; the axial force loading system is used to apply the axial force along the cable.

[0008] The load-bearing beam frame assembly includes columns, cross beams, upper side beams, side beams, diagonal bracing beams, slide bar guide rails, and displacement loading guide rails. Among them, the columns and cross beams respectively form the front frame, the middle frame, and the rear frame, and the upper side beam and the side beam connect the front frame, the middle frame, and the rear frame into a whole; the diagonal bracing beams are respectively installed on the side columns of the front frame and the rear frame to bear the Z-direction load of the test device, the slide bar guide rails are respectively installed on the side columns and the upper and lower cross beams of the front frame and the rear frame, and the displacement loading guide rails are respectively installed on the single-side column and the lower cross beam of the middle frame.

[0009] The slide bar support assembly includes a slide rail support beam, a guide rail end fixing slider, a front-end connecting slider, a rear-end connecting slider, and a sliding bearing. Among them, the front-end connecting slider and the rear-end connecting slider have the same structure, and both are provided with two groups of guide rail holes I in the X and Y directions respectively, and sliding bearings I are installed inside, and the slide rail support beam is placed in each guide rail hole I, and finally fixed with the guide rail end fixing slider, and installed on the slide bar guide rail of the load-bearing frame.

[0010] To ensure the application of the Z-direction load, a group of guide rail holes II are designed in the middle of the front-end connecting slider and a Z-direction sliding bearing II is installed.

[0011] The displacement coordination loading system includes a loading device, a force sensor, a slider bottom plate, a fixed support bottom plate, and a connecting rod. Among them, the loading device and the force sensor are connected by studs to monitor the loading condition of the loading device during the displacement loading process to prevent the occurrence of a stuck shaft.

[0012] The loading device is divided into loading forms in the X and Y directions, including the X-direction loading device I and the Y-direction loading device III, the X-direction loading device II and the Y-direction loading device IV. The bottoms of the X-direction loading device I and the Y-direction loading device III are respectively connected to the slider bottom plate and installed on the displacement loading guide rails of the single-side column and the lower cross beam of the middle frame. The bottoms of the X-direction loading device II and the Y-direction loading device IV are respectively connected to the fixed support base and installed on the single-side column and the lower cross beam of the middle frame. At the same time, the force sensors of the X-direction loading device II and the Y-direction loading device IV are respectively connected to the loading device III and the loading device I by connecting rods.

[0013] The axial force loading system includes an equipment installation platform, a loading device V, a fork ear, a sliding rod, a universal joint, a connecting rod, a force sensor V, and a simulation connecting piece. The side and bottom of the equipment installation platform are fixedly connected to the force sensors of the loading device I and the loading device III respectively. The front part of the equipment installation platform is fixedly connected to the front-end connecting slider. The rear part of the equipment installation platform is fixedly connected to the rear-end connecting slider and the bottom of the loading device V respectively.

[0014] The fork ear is installed at the end of the loading device V and connected to the sliding rod. The sliding rod passes through the front part of the equipment installation platform and the front-end connecting slider and is connected to the universal joint. The universal joint is connected to the force sensor V through the connecting rod. Finally, the simulation connecting piece is installed on the force sensor V.

[0015] The universal joint is a transition device, which functions to release the degrees of freedom in the X and Y directions at the connecting end of the connecting rod and ensure that the force sensor V is always axially loaded along the cable simulation test piece without being affected by forces or torques in other directions. The force sensor V serves as a control end to control the displacement movement of the loading device V by inputting the load. The force sensor serves as a feedback end to monitor the force exerted during the movement of the loading device.

[0016] The cable simulation test piece is a simplified structure of the cable. The entire cable simulation test piece is the object of fatigue testing, including pins, hinge supports, cable clamps, and mooring ropes. The hinge supports are respectively connected to the cable simulation fixing tooling and the axial force loading system through pins. The cable clamps are installed on the hinge supports and fix the mooring ropes.

[0017] The present invention also provides a test method for three-dimensional conical fatigue load loading, including the following steps:

[0018] Step 1, load measurement: According to the working state of the test piece, measure the swing angle range of the test piece in the corresponding state, and measure the actual axial force magnitude range by means of force measurement or strain calibration. The measured parameters obtained are used to establish a force model of the test piece, and the model is optimized under the premise of retaining the force characteristics to obtain a fatigue load spectrum.

[0019] Step 2, test piece installation: Determine the installation distance between the cable simulation fixing tooling and the test device according to the provided length of the test piece. Adjust the loading device in the displacement coordination loading system so that the fixing point of the loading device V of the axial force loading system and the cable simulation fixing tooling are on the same axis. Fine-tune the loading device V to connect the test piece to the axial force loading system.

[0020] Step 3, test debugging: In the displacement coordination loading system, all loading devices use displacement control, and the loading device V in the axial force loading system uses force control. In the test control system, set a small pre-tightening force for the loading device V to tighten the test piece, and control the displacement coordination loading system to move in a circular or elliptical trajectory in the X-Y plane according to the load spectrum. Observe whether there is a sudden change in the force of the force sensors of each loading device to judge whether there is a stuck shaft during the movement. If there is a stuck shaft phenomenon, adjust the relative horizontal and vertical levels of the slide rail of the load-bearing beam frame assembly and the displacement loading rail or eliminate it by adding lubricating oil;

[0021] Step 4, formal test: After the test debugging is completed, conduct the test according to the load spectrum. First, adjust the loading device V and the cable simulation test piece to the same horizontal position, control the force sensor V to the required fatigue load for the test, and jointly control the displacement coordination loading system to control the opening and closing angle;

[0022] Step 5, data acquisition: According to the static test or simulation calculation results of the test piece, use different numbers of loading times as pause points to check whether cracks appear in the structure of the test piece and count the wear values of relevant structures, and record and monitor the displacement and force data of the loading to timely adjust the loading strategy or the structural relationship of the loading system;

[0023] Step 6, end the test: The test stop includes the following three situations: cracks are found in the structure of the test piece during the test pause; the displacement monitored by the loading device V increases and the structure of the test piece undergoes irreversible large deformation; the wear ratio of the easily worn parts in the test piece reaches the replacement index.

[0024] Beneficial effects: (1) By analyzing the working states of flexible connection structural components such as cables and mooring ropes, the present invention proposes a new fatigue loading form, in which the loaded axial force always acts along the axis of the structural component and can rotate in space. This loading form can more realistically reflect the "tension-tension" fatigue life of the structural component in a specific working environment, so as to guide the maintenance and repair of key equipment.

[0025] (2) The present invention decomposes the force and motion characteristics of the structural component, modularizes the loading forms of each state after decomposition in the test device, adjusts the opening and closing angle of the force application point by means of X and Y displacement coordination control, and can design the bottom of the load diagram into different forms of motion states according to relevant mathematical equations. At the same time, combined with the control of the axial force, it can also meet the fatigue life analysis or relevant wear part test work with different requirements.

[0026] (3) The present invention can conduct loading tests in an independent or combined form, can meet the test conditions of large deformation fatigue of structural components in the plane, and the independent motion control programs involved in each loading module are simple, and the reliability of coordinated control is high. Brief Description of the Drawings

[0027] The following further describes the present invention in detail in conjunction with the drawings and specific embodiments, and the above and / or other advantages of the present invention will become clearer.

[0028] Figure 1 It is a schematic diagram of the overall conical fatigue load test device.

[0029] Figure 2 It is a schematic diagram of the load-bearing beam frame assembly.

[0030] Figure 3 It is a schematic diagram of the front and rear frames.

[0031] Figure 4 It is a schematic diagram of the middle frame.

[0032] Figure 5 It is a schematic diagram of the slide bar support assembly.

[0033] Figure 6 It is a schematic diagram of the front connection slider.

[0034] Figure 7 It is a schematic diagram of the sliding bearing installation.

[0035] Figure 8 It is a schematic diagram of the displacement coordination loading system.

[0036] Figure 9 It is a schematic diagram of the axial force loading system.

[0037] Figure 10 It is a schematic diagram of the cable simulation test piece.

[0038] Figure 11 It is a flow chart of the conical fatigue load test method.

[0039] Figure 12 It is a schematic diagram of the circular bottom radius calculation.

[0040] Figure 13 It is a schematic diagram of the fatigue load loading with a circular bottom.

[0041] Figure 14 It is a schematic diagram of the long / short semi-axis calculation of the elliptical bottom.

[0042] Figure 15 It is a schematic diagram of the fatigue load loading with an elliptical bottom.

[0043] Figure 16 It is a schematic diagram of the fatigue load loading with a circular bottom and an axial force as a sine function.

[0044] Figure 17 It is a schematic diagram of the two-dimensional loading amplitude calculation.

[0045] Figure 18 It is a schematic diagram of two-dimensional loading fatigue load. Specific implementation manner

[0046] The present invention provides a test device for three-dimensional conical fatigue load loading, including a load-bearing beam frame assembly 100, a sliding rod support assembly 200, a displacement coordination loading system 300, an axial force loading system 400, a cable simulation test piece 500, and a cable simulation fixing tooling 600, as Figure 1 shown; wherein, the load-bearing beam frame assembly 100 is used to support and fix the sliding rod support assembly 200, the displacement coordination loading system 300, and the axial force loading system 400; the sliding rod support assembly 200 is used to ensure that the loading device moves along the X-Y plane without tipping over; the displacement coordination loading system 300 is used to control the conical opening angle and at the same time play a role in supporting the loading device; the axial force loading system 400 is used to apply the axial force along the cable.

[0047] The load-bearing beam frame assembly 100 includes columns 110, cross beams 120, upper side beams 130, side beams 140, diagonal bracing beams 150, sliding rod guide rails 160, and displacement loading guide rails 170, as Figure 2 shown, wherein the columns 110 and the cross beams 120 respectively form a front frame 101, a middle frame 102, and a rear frame 103, as Figure 3 , Figure 4 shown, and the front frame 101, the middle frame 102, and the rear frame 103 are connected into a whole by the upper side beam 130 and the side beam 140; the diagonal bracing beams 150 are respectively installed on the two side columns 111 of the front frame 101 and the rear frame 102 to bear the Z-direction load of the test device, the sliding rod guide rails 160 are respectively installed on the two side columns 111 and the upper and lower cross beams 121 of the front frame 101 and the rear frame 103, and the displacement loading guide rails 170 are respectively installed on the single side column 112 and the lower cross beam 122 of the middle frame 102.

[0048] The sliding rod support assembly 200 includes a slide rail support beam 210, a guide rail end fixing slider 220, a front end connecting slider 230, a rear end connecting slider 240, and a sliding bearing 250, as Figure 5 shown, wherein the front end connecting slider 230 and the rear end connecting slider 240 have similar structures. Both are respectively provided with two groups of guide rail holes I231 in the X and Y directions, and sliding bearings I251 are installed inside. The slide rail support beam 210 is placed in each guide rail hole I231, and finally fixed with the guide rail end fixing slider 220 and installed on the sliding rod guide rail 160 of the load-bearing frame. The difference between the two is that the front end connecting slider 230 also needs to design a group of guide rail holes II232 in the middle and install a Z-direction sliding bearing II252 to ensure the application of the Z-direction load, asFigure 6 , Figure 7 as shown

[0049] The displacement coordination loading system 300 includes a loading device 310, a force sensor 320, a slider base plate 330, a fixed support base plate 340, and a connecting rod 350, as Figure 8 shown. Among them, the loading device 310 and the force sensor 320 are connected by studs, which are used to monitor the loading conditions of each loading device 310 during the displacement loading process to prevent the occurrence of stuck shafts. The loading device 310 is divided into loading forms in two directions, X and Y, including the X-direction loading device I 311 and the Y-direction loading device III 313, and the X-direction loading device II 312 and the Y-direction loading device IV 314. The bottoms of the X-direction loading device I 311 and the Y-direction loading device III 313 are respectively connected to the slider base plate 330 and are installed on the displacement loading guide rails 170 of the middle load-bearing frame columns 112 and the bottom cross beam 122. The bottoms of the X-direction loading device II 312 and the Y-direction loading device IV 314 are respectively connected to the fixed support base 340 and are installed on the columns 112 and the bottom cross beam 122 of the middle load-bearing frame. At the same time, the force sensors 320 of the X-direction loading device II 312 and the Y-direction loading device IV 314 are respectively connected to the loading device III 313 and the loading device I 311 by the connecting rod 350. The connection design of the displacement coordination loading system 300 is that there are two displacement loadings with larger spans acting together in the same direction, ensuring the smoothness of the loading process and minimizing the bending moment influence caused by the self-weight of the loading device 310 and related connection toolings to the greatest extent.

[0050] The axial force loading system 400 includes an equipment installation platform 410, a loading device V 420, a fork ear 430, a slide bar 440, a universal joint 450, a connecting rod 460, a force sensor V 470, and a simulation connecting piece 480, as Figure 9As shown, the side and bottom of the equipment installation platform 410 are fixedly connected to the force sensors 320 of the loading device I 311 and the loading device III 313 respectively. The front part of the equipment installation platform 410 is fixedly connected to the front-end connection slider 230. The rear part of the equipment installation platform 410 is fixedly connected to the rear-end connection slider 240 and the bottom of the loading device V 420 respectively. The fork ear 430 is installed at the end of the loading device V 420 and connected to the slide bar 440. The slide bar 440 passes through the front part of the equipment installation platform 410 and the front-end connection slider 230 and is connected to the universal joint 450. The universal joint 450 is connected to the force sensor V 470 through the connecting rod 460. Finally, the simulation connector 480 is installed on the force sensor V 470, and it can be replaced according to the actual connection form of the cable simulation test piece 500. The universal joint 450 is a transition device, and its function is to release the degrees of freedom in the X and Y directions of the connecting end of the connecting rod 460 and make the force sensor V 470 always receive axial force along the cable simulation test piece 500 without being affected by forces or torques in other directions, improving the force control accuracy. The difference between the force sensor V 470 and the force sensor 320 is that the force sensor V 470 is used as the control end to control the displacement movement of the loading device V 420 through the input load, and the force sensor 320 is used as the feedback end, and its function is to monitor the force received during the movement of the loading device 310.

[0051] The cable simulation test piece 500 is a simplified structure of the cable, and the entire cable simulation test piece 500 is the object of fatigue testing. As Figure 10 shown, it includes a pin 501, a hinge support 502, a cable clamp 503, and a mooring rope 504. The hinge support 502 is respectively connected to the cable simulation fixing tooling 600 and the axial force loading system 400 through the pin 501. The cable clamp 503 is installed on the hinge support 502 and fixes the mooring rope 504.

[0052] For studying the fatigue and wear performance of key components of flexible connection structures such as cables under the influence of non-axial external forces, the present invention proposes a test method for three-dimensional conical fatigue load loading. The test process of this method is as Figure 11 shown, and the specific implementation steps are as follows:

[0053] (1) Load measurement: According to the working state of the test piece, measure the swing angle range in its corresponding state, and measure the actual axial force magnitude range by means of force measurement or strain calibration. The measured parameters obtained by the above two methods are used to establish the force model of the test piece, and the model is optimized under the premise of retaining the force characteristics to obtain the fatigue load spectrum;

[0054] (2) Specimen installation: Determine the approximate installation distance between the cable simulation fixture 600 and the test device based on the provided length of the test piece. Adjust the loading device 310 in the displacement coordination loading system 300 so that the loading device V420 of the axial force loading system 400 and the fixed point of the cable simulation fixture 600 are on the same axis. Fine-tune the loading device V420 to connect the test piece to the axial force loading system 400;

[0055] (3) Test debugging: All loading devices 310 in the displacement coordination loading system 300 use displacement control, and the loading device V420 of the axial force loading system 400 uses force control. Set a small pre-tightening force in the test control system to tighten the test piece with the loading device V420. Control the displacement coordination loading system 300 to move in a circular or elliptical trajectory in the X-Y plane according to the load spectrum, and observe whether there is a sudden change in the force of the force sensors 320 of each loading device 310 to judge whether there is a stuck axis during its movement. If there is a stuck axis phenomenon, adjust the relative horizontal and vertical degrees of the sliding rod guide 160 and the displacement loading guide 170 in the load-bearing beam frame assembly 100 or add lubricating oil to eliminate it;

[0056] (4) Formal test: After the test debugging is completed, conduct the test according to the load spectrum. First, adjust the loading device V420 and the cable simulation test piece 500 to the same horizontal position, control the force sensor V470 to the required fatigue load, and jointly control the displacement coordination loading system 300 to control the opening and closing angle. Four relatively typical loading conditions are listed for illustration:

[0057] a) Constant force, conical load with a circular bottom

[0058] Calculate the moving radius r of the circle using the swing angle θ calculated by the model and the horizontal distance L from the fixed point of the test piece to the universal joint, that is, r = Ltanθ, as Figure 12 shown:

[0059] In order to eliminate the additional torque generated by the self-weight and base friction of the loading device I311 and the loading device III313 during the movement in the displacement coordination loading system 300 of the device of the present invention, it is necessary to equip the corresponding auxiliary loading device II312 and the loading device IV313. Therefore, the displacement coordination loading system 300 arranges the Y-direction loading device III313 and the loading device IV314 in the same direction. Due to space limitations, the corresponding X-direction loading device I311 and the loading device II312 are arranged in the opposite direction, and vice versa can achieve the same effect.

[0060] First, set the displacement loading curve equation of the Y-direction loading device III313 and the loading device IV314 as:

[0061] Y = rsinωt

[0062] Among them, Y represents the motion trajectories of loading device III 313 and loading device IV 314, r represents the motion amplitude, ω represents the angular frequency, and t represents the motion time.

[0063] In the X direction, there should be a phase difference of π / 2. The displacement loading curve equation of loading device I 311 is:

[0064] X 1 = rsin(ωt + π / 2) = rcosωt

[0065] Among them, X 1 represents the motion trajectory of loading device I 311, r represents the motion amplitude, ω represents the angular frequency, and t represents the motion time.

[0066] Also, since the loading devices in the X direction are arranged in reverse, the displacement loading curve equation of loading device II 312 is:

[0067] X II = -rcosωt

[0068] Among them, X II represents the motion trajectory of loading device II 312, r represents the motion amplitude, ω represents the angular frequency, and t represents the motion time.

[0069] Finally, the overall motion equation is

[0070] X 2 + Y 2 = (rcosωt) 2 + (rsinωt) 2 = r 2

[0071] Among them, r = Ltanθ, indicating that the loading method satisfies the equation of a circle. At this time, if loading device V 420 adopts constant force control, a conical fatigue load with a circular bottom surface is obtained, as Figure 13 shown.

[0072] b) Conical load with a constant force and an elliptical bottom surface:

[0073] Similar to the calculation method for a circular bottom surface, the major semi-axis and minor semi-axis of the bottom ellipse are calculated using the angles α corresponding to the major semi-axis and β corresponding to the minor semi-axis in the mechanical model, that is, the major semi-axis length a = Ltanα, and the minor semi-axis length b = Ltanβ, as Figure 14 shown;

[0074] Using the same displacement loading setting method as in subsection a), the displacement loading curve equations of loading device III 313 and loading device IV 314 in the Y direction are:

[0075] Y = bsinωt

[0076] Among them, Y represents the motion trajectories of the loading device III 313 and the loading device IV 314, b represents the motion amplitude in the Y direction, ω represents the angular frequency, and t represents the motion time.

[0077] The displacement loading curve equations of the loading device I 313 and the loading device II 312 in the X direction are respectively:

[0078] X 1 = a sin(ωt + π / 2) = a cos ωt

[0079] X II = -a cos ωt

[0080] Among them, X 1 represents the motion trajectory of the loading device I 311, X II represents the motion trajectory of the loading device II 312, a represents the motion amplitude in the X direction, ω represents the angular frequency, and t represents the motion time.

[0081] Finally, the overall motion equation is obtained as:

[0082]

[0083] Among them, a = L tanα, b = L tanβ, indicating that the loading method satisfies the ellipse equation. At this time, if the loading device V 420 adopts constant force control, a conical fatigue load with an elliptical bottom surface is obtained, as Figure 15 shown.

[0084] c) The conical load with a circular bottom surface and a sinusoidally varying force:

[0085] To ensure the authenticity of the axial load on the test piece, the force sensor V 470 in the axial force loading system 400 is connected to the test piece and moves simultaneously with it in space, and the loading device V 420 is controlled by means of force loading, then the force form on the axial direction of the test piece can be designed more intuitively.

[0086] If the axial force F z adopts the form of a sine wave, that is:

[0087] F z = A + f sin ωt

[0088] Among them, F z represents the axial force, A represents the average value of the axial force, f represents the amplitude of the axial force, ω represents the angular frequency, and t represents the motion time;

[0089] Then the schematic diagram of the loading fatigue load as shown in Figure 16 can be obtained.

[0090] d) The force varies sinusoidally, the displacement in the X direction is constant, and the movement in the Y direction

[0091] The working condition is the fatigue condition of two-dimensional planar motion, aiming to test the influence of the included angle γ of the motion in the plane and the axial force F on the fatigue life of the test piece. Therefore, the influence factor of the included angle can be first converted into the displacement loading amplitude d, that is, d = Ltanγ, as Figure 17 shown.

[0092] Then, first set X = 0, and the displacement loading curve equations of the loading device III313 and the loading device IV314 in the Y direction are as follows:

[0093] Y = dsinωt

[0094] where Y represents the motion trajectories of the loading device III313 and the loading device IV314, d represents the motion amplitude in the Y direction, ω represents the angular frequency, and t represents the motion time.

[0095] The axial force adopts the form of a sine wave:

[0096] F = A + fsinωt

[0097] where F z represents the axial force, A represents the mean value of the axial force, f represents the amplitude of the axial force, ω represents the angular frequency, and t represents the motion time;

[0098] Then, the schematic diagram of the loading fatigue load as shown in Figure 18 can be obtained.

[0099] (5) Data acquisition: According to the static test or simulation calculation results of the test piece, different loading times are used as pause points (for example, N = 10 5 or N = 10 6 ) to check whether cracks appear in the structure of the test piece and to count the wear values of relevant structures, and record and monitor the data of the loaded displacement and force to timely adjust the loading strategy or the structural relationship of the loading system.

[0100] (6) End of the test: The test stop can be divided into 3 cases: cracks are found in the structure of the test piece during the test pause; the displacement monitored by the loading device V420 increases and irreversible large deformation occurs in the structure of the test piece; the wear ratio of the easily worn parts in the test piece reaches the replacement index (for example, wear ratios of 5%, 8%, or 10%).

[0101] Currently, the test devices described in the relevant patents of the triaxial fatigue test research are mostly established for parts such as bearings and bushings, and there are few triaxial fatigue test devices based on component level. Therefore, the test device of the present invention is established to study the "tension-tension" fatigue life of the whole flexible connection mechanism under relevant working conditions and the wear problems of each connecting component.

[0102] The conical fatigue load test device proposed by the present invention is a new method constructed based on the spatial force condition of the hinged end and used to test the fatigue life of relevant connection key components. By using the circle or ellipse equation, the displacement in the X and Y directions can be coordinately loaded, and the simulation of the opening and closing angles in different directions during the spatial movement of the hinged end can be realized. At the same time, the present invention connects the force sensor with the test piece, and the axial force of the test piece can be controlled through the input of force. Combining the above-mentioned opening and closing angles, the loading problem of the conical fatigue load test of the flexible connection is solved.

[0103] In addition, each loading module in the test device of the present invention can independently control the load, which can not only realize three-dimensional loading, but also meet the fatigue test conditions of the test piece in the two-dimensional plane in the form of "two by two" combination.

[0104] The present invention provides a test device and a test method for three-dimensional conical fatigue load loading. There are many specific methods and ways to implement this technical solution. The above is only the preferred implementation mode of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be realized by the prior art.

Claims

1. A test device for three-dimensional cone fatigue loading, characterized in that: It comprises a load-bearing beam frame assembly (100), a slide rod support assembly (200), a displacement coordination loading system (300), an axial force loading system (400), a cable simulation test piece (500) and a cable simulation fixing tool (600); The load-bearing beam frame assembly (100) is used to support and fix the slide bar support assembly (200), the displacement coordination loading system (300) and the axial force loading system (400); the slide bar support assembly (200) is used to ensure that the loading device moves along the XY plane without tipping over; the displacement coordination loading system (300) is used to control the conical opening and closing angle and simultaneously supports the loading device; the axial force loading system (400) is used to apply an axial force along the cable.

2. The device according to claim 1, characterized in that The load-bearing beam frame assembly (100) comprises a column (110), a cross beam (120), an upper side beam (130), a side beam (140), a diagonal support beam (150), a slide bar guide rail (160) and a displacement loading guide rail (170), wherein the column (110) and the cross beam (120) respectively form a front frame (101), a middle frame (102) and a rear frame (103), and the upper side beam (130) and the side beam (140) connect the front frame (101), the middle frame (102) and the rear frame The front frame (101) and the rear frame (103) are connected as a whole; the diagonal bracing beam (150) is respectively installed on the two side columns (111) of the front frame (101) and the rear frame (102) to bear the Z-direction load of the test device; the sliding rod guide rail (160) is respectively installed on the two side columns (111) and the upper and lower cross beams (121) of the front frame (101) and the rear frame (103); the displacement loading guide rail (170) is respectively installed on the single side column (112) and the lower cross beam (122) of the middle frame (102).

3. The device according to claim 2, characterized in that The slide bar support assembly (200) comprises a slide rail support beam (210), a guide rail end fixing slider (220), a front end connecting slider (230), a rear end connecting slider (240) and a sliding bearing (250), wherein the front end connecting slider (230) and the rear end connecting slider (240) have the same structure, and are respectively provided with two groups of guide rail holes I (231) in the X and Y directions, and are both installed with sliding bearings I (251) inside, and the slide rail support beam (210) is placed in each guide rail hole I (231), and finally fixed with the guide rail end fixing slider (220), and installed on the slide bar guide rail (160) of the load-bearing frame.

4. The device according to claim 3, characterized in that In order to ensure the application of the Z-direction load, the front end connecting slider (230) is designed with a group of guide rail holes II (232) in the middle thereof and is equipped with a Z-direction sliding bearing II (252).

5. The device according to claim 4, characterized in that The displacement coordinated loading system (300) comprises a loading device (310), a force sensor (320), a slider base plate (330), a fixed support base plate (340) and a connecting rod (350), wherein the loading device (310) and the force sensor (320) are connected by means of a stud, and are used to monitor the loading condition of the loading device (310) during the displacement loading process to prevent the occurrence of a stuck shaft.

6. The device according to claim 5, characterized in that The loading device (310) is divided into two loading forms in the X direction and the Y direction, including an X-direction loading device I (311) and a Y-direction loading device III (313), an X-direction loading device II (312) and a Y-direction loading device IV (314), wherein the bottoms of the X-direction loading device I (311) and the Y-direction loading device III (313) are respectively connected to the slider bottom plate (330) and are installed on the displacement loading device of the single-side column (112) and the lower crossbeam (122) of the middle frame (102). On the guide rail (170), the bottoms of the X-direction loading device II (312) and the Y-direction loading device IV (314) are respectively connected to the fixed support base (340), and are installed on the single-side column (112) and the lower crossbeam (122) of the middle frame (102). At the same time, the force sensors (320) of the X-direction loading device II (312) and the Y-direction loading device IV (314) are respectively connected to the loading device III (313) and the loading device I (311) by using connecting rods (350).

7. The device according to claim 6, characterized in that The axial force loading system (400) comprises an equipment installation platform (410), a loading device V (420), a fork ear (430), a slide rod (440), a universal joint (450), a connecting rod (460), a force sensor V (470) and a simulation connecting piece (480), wherein the side and bottom of the equipment installation platform (410) are respectively fixedly connected to the force sensors (320) of the loading device I (311) and the loading device III (313), the front of the equipment installation platform (410) is fixedly connected to the front connecting slider (230), and the rear of the equipment installation platform (410) is respectively fixedly connected to the rear connecting slider (240) and the bottom of the loading device V (420).

8. The device according to claim 7, characterized in that The fork ear (430) is installed at the end of the loading device V (420) and connected to the slide bar (440). The slide bar (440) passes through the front of the device installation platform (410) and the front end connecting slider (230) and is connected to the universal joint (450). The universal joint (450) is connected to the force sensor V (470) through the connecting rod (460). Finally, the simulation connecting piece (480) is installed on the force sensor V (470).

9. The device according to claim 8, characterized in that The universal joint (450) is a transition device, which functions to release the X and Y degrees of freedom of the connection end of the connecting rod (460) and to make the force sensor V (470) always be subjected to force along the axial direction of the cable simulation test piece (500) without being affected by forces or moments in other directions; the force sensor V (470) serves as a control end, and controls the displacement movement of the loading device V (420) by inputting a load, and the force sensor (320) serves as a feedback end, and functions to monitor the force applied to the loading device (310) during the movement process; The cable simulation test piece (500) is a simplified cable structure, and the entire cable simulation test piece (500) is a fatigue test object, including a pin (501), a hinge support (502), a cable clamp (503), and a mooring rope (504), wherein the hinge support (502) is respectively connected to the cable simulation fixing tool (600) and the axial force loading system (400) through the pin (501), and the cable clamp (503) is installed on the hinge support (502) and fixes the mooring rope (504).

10. A test method for three-dimensional cone fatigue loading, characterized in that: The steps include: Step 1, load measurement: according to the working state of the test piece, the swing angle range of the test piece under the corresponding state is tested, and the actual axial force range is measured by force measurement or strain calibration. The measured parameters are used to establish the force model of the test piece, and the model is optimized under the premise of retaining the force characteristics to obtain the fatigue load spectrum; Step 2, test piece installation: determine the installation distance between the cable simulation fixture (600) and the test device according to the provided length of the test piece, adjust the loading device (310) in the displacement coordination loading system (300) so that the loading device V (420) of the axial force loading system (400) and the fixing point of the cable simulation fixture (600) are on the same axial direction, and fine-tune the loading device V (420) to connect the test piece with the axial force loading system (400); Step 3, test debugging: the loading devices (310) in the displacement coordinated loading system (300) all use displacement control, and the loading device V (420) of the axial force loading system (400) uses force control. In the test control system, a smaller preload force is set for the loading device V (420) to tighten the test piece. The displacement coordinated loading system (300) is controlled to move in a circular or elliptical trajectory in the XY plane according to the load spectrum. It is observed whether the force sensor (320) of each loading device (310) has a sudden change in force to determine whether the shaft is stuck during the movement process. If the shaft is stuck, the relative horizontality and relative verticality of the sliding rod guide rail (160) and the displacement loading guide rail (170) in the load-bearing beam frame assembly (100) are adjusted or lubricating oil is added to eliminate the problem. Step 4, formal test: After the test debugging is completed, the test is carried out according to the load spectrum. First, the loading device V (420) and the cable simulation test piece (500) are adjusted to the same horizontal position, the force sensor V (470) is controlled to the fatigue load required for the test, and the displacement coordination loading system (300) is coordinated to control the opening and closing angle; Step 5, data collection: according to the static test or simulation calculation results of the test piece, different loading times are used as pause points to check whether cracks appear in the structure of the test piece and to calculate the wear value of the relevant structure, and the displacement and force data of the loading are recorded and monitored to adjust the loading strategy or the structural relationship of the loading system in a timely manner; Step 6, end the test: The test is stopped in the following three situations: cracks are found in the structure of the test piece during the test pause; the displacement monitored by the loading device V (420) increases and the structure of the test piece undergoes irreversible large deformation; the wear ratio of the easily worn parts in the test piece reaches the replacement index.

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