A dynamic submarine cable vertical fatigue test device and method based on a topological optimization design framework

Abstract

The application provides a kind of dynamic submarine cable vertical fatigue test testing device and method based on topological optimization design framework, device includes swing head, main body frame, dynamic submarine cable, connecting hinge, support frame, bottom plate and tensile actuator, swing head is installed on the upper plate on the top of main body frame, main body frame, support frame and tensile actuator are all installed on bottom plate;The upper end of dynamic submarine cable is connected with swing head by clamping mechanism, the left and right ends of swing head are each connected with bending actuator, bending actuator is connected on the upper plate, for realizing the reciprocating swing of swing head, to realize the bending loading of dynamic submarine cable in turn;The lower end of dynamic submarine cable is connected with connecting hinge, connecting hinge is slidably connected on support frame, tensile actuator is connected with connecting hinge, for realizing the displacement movement of connecting hinge, to realize the tensile loading of dynamic submarine cable in turn.The application can better simulate the actual working condition of dynamic submarine cable, so that the fatigue strength error of measurement and calculation becomes smaller, and is not affected by additional gravity when measuring.

Description

Technical Field

[0001] This invention relates to the field of fatigue testing equipment technology, and more particularly to a dynamic submarine cable vertical fatigue testing device and method based on a topology optimization design framework. Background Technology

[0002] The ocean is now the world's largest energy reserve, and countries around the world are focusing their attention on the development of marine resources. While marine resource extraction projects are developing, the scientific and technological levels of various countries are also constantly improving. People are no longer limited to the development of marine resources in shallow waters and have begun to develop various new extraction equipment to explore and research deep-water areas. New extraction equipment is mainly divided into two types: fixed platform extraction systems and mobile platform extraction systems. Among them, floating offshore wind power platforms, which connect floating wind turbines to the equipment required for power supply on the seabed via dynamic submarine cables, are key equipment for realizing the development, long-distance transmission, and large-scale utilization of near-shore and offshore wind energy resources. Because dynamic submarine cables operate in the marine environment for extended periods, they are prone to fatigue failure due to the influence of ocean waves and the relative motion of the floating body. Therefore, fatigue strength testing is necessary during the manufacturing process.

[0003] Currently, dynamic submarine cables play a decisive role in offshore oil and gas development; it can be said that offshore oil and gas pipeline transportation is inseparable from dynamic submarine cables. Due to the external loads generated by waves and currents in the ocean, these external factors cause dynamic submarine cables to be subjected to cyclic loads. To avoid excessive bending of dynamic submarine cables caused by loads from waves, currents, and other environmental factors, a certain degree of stiffness should be maintained both internally and externally. Generally, dynamic submarine cables adopt a multi-layered helical winding composite structure. This structure not only improves the strength and stiffness of the dynamic submarine cable but also ensures its bending compliance. Because dynamic submarine cables have a multi-layered helical winding composite structure and nonlinear geometric characteristics, conventional numerical and theoretical methods are difficult to obtain accurate results. There is an urgent need for a fatigue testing device that can simulate the mechanical behavior of submarine cables caused by waves, currents, and the relative motion of floating bodies. To date, only a few countries in the world, such as Norway and Brazil, have conducted fatigue life tests simulating in-situ operating conditions for dynamic submarine cables. Although my country has made progress in the research and manufacturing of dynamic submarine cables in recent years, fatigue testing equipment is relatively scarce, and breakthroughs are urgently needed in the research and manufacturing of vertical fatigue testing devices. Furthermore, horizontal fatigue testing devices cannot fully simulate the in-situ operating conditions of dynamic submarine cables because the accuracy of the test data is affected by the weight of the dynamic submarine cable itself. To make the test results of dynamic submarine cables more accurate, this invention designs a vertical fatigue testing device for dynamic submarine cables based on a topology optimization design framework. Summary of the Invention

[0004] To address the aforementioned technical issues, a dynamic submarine cable vertical fatigue test device and method based on a topology optimization design framework are provided.

[0005] The technical means employed in this invention are as follows:

[0006] A dynamic submarine cable vertical fatigue test device based on a topology optimization design framework includes: a swing head, a main frame, a dynamic submarine cable, a connecting hinge, a support frame, a base plate, and a tension actuator. The swing head is installed on the upper plate at the top of the main frame, and the main frame, the support frame, and the tension actuator are all installed on the base plate. The dynamic submarine cable is placed vertically in the internal space of the main frame.

[0007] The upper end of the dynamic submarine cable is connected to the swing head through a clamping mechanism. Each end of the swing head is connected to a bending actuator, which is connected to the upper plate to realize the reciprocating swing of the swing head, thereby realizing the bending load on the dynamic submarine cable.

[0008] The lower end of the dynamic submarine cable is connected to a connecting hinge, which is slidably connected to a support frame. The tension actuator is connected to the connecting hinge and is used to realize the displacement movement of the connecting hinge, thereby realizing the tension loading on the dynamic submarine cable.

[0009] Furthermore, the swing head adopts a solid-web frame structure and is connected to a bending actuator through a bending mechanism. The bending actuator is connected to a hinged support on the main frame.

[0010] Furthermore, the bending mechanism includes a connecting rod and a gear and rack mechanism. The gear and rack mechanism includes at least a gear and a rack. One end of the connecting rod is connected to the swing head by a first bolt, and the other end is connected to the rack by a second bolt. The rack and gear are meshed and connected for transmission. The gear is connected to the bending actuator. The lower end of the rack and gear mechanism is fixed to the upper plate of the main frame by a screw connection.

[0011] Furthermore, the upper part of the connecting hinge is connected to the lower end of the dynamic submarine cable via a submarine cable fixing device. The connecting hinge includes a hinge hole, a hinge support, a lifting platform, and a force-saving pulley system. The lifting platform is slidably connected to the support frame, the hinge support is fixed to the lifting platform, the hinge hole is opened on the hinge support, and the hinge hole is connected to the submarine cable fixing device through internally mating bolts. The lower part of the lifting platform is connected to the force-saving pulley system, which consists of two pulleys and a steel wire rope. One end of the steel wire rope is fixedly connected to the lower pulley and wound around the two pulleys, and the other end is connected to the tension actuator. The upper pulley is connected to the lifting platform, and the lower pulley is connected to the base plate.

[0012] The tension actuator controls the displacement movement of the connecting hinge by controlling the force-saving pulley system, thereby realizing the tension loading of the dynamic submarine cable; at the same time, the force-saving pulley system is used to compensate for the small displacement generated at the end of the dynamic submarine cable when the head swings.

[0013] Furthermore, the swing head is connected to the main frame via a shaft, wherein a bearing seat is welded to the upper plate of the main frame, a bearing is installed in the bearing seat, and the bearing is connected to the shaft connected to the swing head.

[0014] The upper end of the swing head is provided with a cover plate, which is fixed to the swing head by multiple screws. The installation and removal of the dynamic submarine cable are achieved by opening the cover plate.

[0015] Furthermore, an anti-bend device is installed at the connection between the dynamic submarine cable and the swing head. The anti-bend device has a three-section structure, and the materials of the three-section structure are polyurethane and epoxy resin.

[0016] Furthermore, both the bending actuator and the stretching actuator are hydraulic actuators.

[0017] Furthermore, the main frame is welded from open-type steel and consists of a triangular truss structure, forming a tower-like structure with a triangular truss support structure.

[0018] The lower end of the main frame has multiple rows of second bolt holes and multiple rows of third bolt holes, and bolts are connected in the second bolt holes and third bolt holes. The main frame is connected to the base plate through the second bolt holes, third bolt holes and bolts. The lower end of the support frame has a first bolt hole, and the support frame is connected to the base plate through bolts connected in the first bolt hole.

[0019] Furthermore, it also includes an information monitoring system, which at least includes sensors, cameras, and data analysis software. The sensors are installed on the surface of the dynamic submarine cable, and strain gauges are also installed on the surface of the dynamic submarine cable. The sensors and strain gauges are attached to the dynamic submarine cable at equal distances and are electrically connected to the host computer. The test data is collected and transmitted to the host computer through the strain gauges and sensors, and the data analysis software is used to analyze the stress and fatigue failure of the dynamic submarine cable. The sensors are installed at the upper and lower ends of the main frame, and the camera records the real-time working conditions and changes of the dynamic submarine cable and the fatigue testing machine.

[0020] This invention also provides a testing method for a dynamic submarine cable vertical fatigue testing device based on a topology optimization design framework, comprising the following steps:

[0021] S1. Assemble the various parts and mechanisms to obtain the test device. Connect the bending actuator and support frame to the upper plate and bottom plate of the main frame respectively. At the same time, turn off the switches of each actuator. Adjust the corresponding actuator according to the motion mode required for each test. The upper section of the dynamic submarine cable is fixed to the swing head through the clamping mechanism, and the lower end is connected to the tension actuator through the connecting hinge. The direction of the tension actuator is adjusted by the force-saving pulley group to ensure that the dynamic submarine cable is in a vertical state.

[0022] S2. Based on the test requirements, the sensors and strain gauges are attached to the surface of the dynamic submarine cable at equal intervals. The sensors are installed at the connection between the dynamic submarine cable and the swing head and tension actuator. Finally, it is determined whether each sensor is attached and installed firmly to prevent the sensors from falling off during the test, which would affect the acquisition of test data.

[0023] S3. After installing the above sensors and strain gauges, perform preliminary debugging of the testing device: apply small-amplitude loads to the dynamic submarine cable using the bending actuator and tension actuator respectively, observe the sensor recordings, and start the test once the test requirements are met.

[0024] S4. Control the movement of the bending actuator, the swing head begins to swing, and at the same time drives the dynamic submarine cable to swing left and right, finally completing the bending load on the dynamic submarine cable; control the left and right swing of the dynamic submarine cable by controlling the extension and retraction of the bending actuator, simulating the in-situ working environment of the dynamic submarine cable under the influence of ocean currents.

[0025] S5. The tension actuator controls the movement of the connecting hinge by pulling the steel wire rope of the labor-saving pulley block, thereby driving the dynamic submarine cable to achieve axial loading of fixed tension.

[0026] Based on the experimental requirements, there are two types of experiments:

[0027] The first type is the fatigue test, which first drives the tension actuator and the bending actuator, and then drives the dynamic submarine cable to undergo tensile loading and bending swing, ultimately causing the dynamic submarine cable to bear tensile and bending loads.

[0028] The second type is the tensile test. First, only the tensile actuator is moved, which drives the dynamic submarine cable to perform tensile movements, and finally makes the dynamic submarine cable bear tensile load.

[0029] In the above experiment, the camera located on the main frame captured the entire deformation process of the dynamic submarine cable. At the same time, the data collected by the sensors and strain gauges were analyzed and processed by relevant software. Finally, the results were compared with the theoretical calculation results, and the stress and life calculation of the dynamic submarine cable were obtained by combining the two results.

[0030] Each of the above experiments can be repeated multiple times to reduce error.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1. The test device of the present invention is based on topology optimization and the main frame of the test device is designed to be lightweight. After optimization, the main frame of the test device is tower-shaped, which reduces the weight while meeting the strength requirements, improves the material utilization rate, and makes the test device easier to move.

[0033] 2. This invention installs a force-saving pulley system between the tension actuator and the dynamic submarine cable, which reduces the tonnage of the actuator required for loading and lowers costs. Simultaneously, the force-saving pulley system can compensate for displacement at the fixed end of the dynamic submarine cable during its swing, preventing premature failure at the cable's end. The force-saving pulley system achieves redundancy and compatibility in end-tensioning through minute displacements, reducing its impact on the dynamic submarine cable and improving the reliability of test data.

[0034] 3. This invention places two hydraulic actuators on each side of the swing head to achieve bending loading on the dynamic submarine cable. The dual-side dual-hydraulic design makes the test more accurate and the operation more convenient. Individual control can also achieve more different bending loading forms, and fatigue tests of dynamic submarine cables under different degrees of bending load can be carried out. It can simulate the bending behavior of dynamic submarine cables under different marine environmental conditions in more sea areas, making the test data more reliable.

[0035] 4. The main frame of this invention is divided into four sections, each of which is welded from open-type steel, ensuring both safety and economy.

[0036] 5. The hydraulic actuators of the present invention are independent of each other, and can effectively control the application of their respective loads. At the same time, the loading sequence can be arbitrarily changed according to engineering and design requirements.

[0037] 6. This invention, as a key piece of equipment for dynamic submarine cable fatigue testing, is the subject of research by only a handful of companies worldwide, and is the first of its kind in China. This invention effectively breaks the technological monopoly, fills a domestic gap, and provides reliable experimental data for research on the fatigue performance of dynamic submarine cables in my country.

[0038] 7. Compared with the horizontal fatigue testing machine, the present invention can better simulate the actual working conditions of dynamic submarine cables, thereby reducing the error of fatigue strength measurement and calculation, and is not affected by additional gravity during measurement.

[0039] 8. In calculating tensile and bending loads, gravity and tension are in the same direction. They can be considered as a resultant force during the calculation, which makes the calculation convenient, the data accurate, and allows for more precise analysis of the fatigue strength of dynamic submarine cables.

[0040] 9. The vertical fatigue testing machine of the present invention not only has the advantages of high control accuracy, high measurement accuracy and good heat dissipation performance, but also has the advantages of convenient installation of dynamic submarine cables and small footprint compared with the horizontal fatigue testing machine.

[0041] Based on the above reasons, this invention can be widely applied in fields such as dynamic submarine cable testing. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of the main structure of the dynamic submarine cable vertical fatigue test device based on the topology optimization design framework in a specific embodiment of the present invention.

[0044] Figure 2 This is a partial cross-sectional view of the swing head of the dynamic submarine cable vertical fatigue test device based on the topology optimization design framework in a specific embodiment of the present invention.

[0045] Figure 3 This is a schematic diagram of the tensile device of the dynamic submarine cable vertical fatigue test device based on the topology optimization design framework in a specific embodiment of the present invention.

[0046] Figure 4 This is a schematic diagram of the base plate of the dynamic submarine cable vertical fatigue test device based on the topology optimization design framework in a specific embodiment of the present invention.

[0047] In the diagram: 1. Swing head; 2. Bearing; 3. Bearing housing; 4. Anti-bending device; 5. Main frame; 6. Dynamic submarine cable; 7. Submarine cable fixing device; 8. Connecting hinge; 9. Support frame; 10. Base plate; 11. Tensioning actuator; 101. Cover plate; 102. Screw; 103. First bolt; 104. Connecting rod; 105. Second bolt; 106. Rack; 107. Bending actuator; 801. Hinge hole; 802. Hinge support; 803. Lifting platform; 804. Effort-saving pulley block; 1001. First bolt hole; 1002. Second bolt hole; 1003. Third bolt hole. Detailed Implementation

[0048] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0051] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0052] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0053] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0054] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0055] This invention provides a dynamic submarine cable vertical fatigue testing device based on a topology optimization design framework, comprising:

[0056] The swing head 1 can achieve the purpose of testing and calculating the bending fatigue strength of the dynamic submarine cable 6, mainly manifested as reciprocating periodic oscillation;

[0057] The main frame 5 not only provides support for the dynamic submarine cable testing device and interfaces for installing other devices, but also bears the bending moment and tensile and compressive loads generated by the actuator during the test.

[0058] The hydraulic actuators, the reciprocating periodic oscillation of the swing head 1 and the axial tension at the end of the dynamic submarine cable 6 are provided by the bending actuator 107 connected to the left and right ends of the swing head 1 and the tension actuator 11 of the base plate 10, respectively.

[0059] The labor-saving pulley block 804, consisting of pulleys and steel wire rope, is used to change the orientation of the bottom tension actuator 11 from vertical loading to horizontal loading, thereby reducing the overall height of the test device. At the same time, the labor-saving pulley block 804 reduces the load of the tension actuator 11 by half. It can also be used to compensate for the small displacement caused by the reciprocating swing of the pendulum head 1 at the bottom fixed point of the dynamic submarine cable 6.

[0060] The anti-bend device 4 is used to suppress the sudden curvature change of the dynamic submarine cable 6 during the process of being subjected to alternating stress, and to realistically simulate the in-situ installation state of the dynamic submarine cable 6.

[0061] The swing head 1 is composed of a solid-web frame structure and is located at the top of the vertical fatigue testing machine. The bending actuator 107, which serves as the power end, is connected to the swing head 1 and the hinged support on the main frame 5 through gear and rack transmission. The two achieve reciprocating swing through the transmission mechanism of half gear and rack, thereby simulating the effect of the marine environment on the bending load of the dynamic submarine cable 6 and the bending moment brought to the dynamic submarine cable 6 by the waves and currents in the ocean. The swing head 1 is connected to the main frame 5 by a shaft. First, the bearing seat 3 that meets the requirements is welded on the main frame 5. Then, the main frame 5 is hinged to the swing head 1 through the shaft. One end of the dynamic submarine cable 6 is fixed to the end of the swing head 1 by a clamping mechanism and bolts.

[0062] The main frame 5 is welded from open-type steel and serves as a support in the entire device. Two bending actuators 107 (hydraulic actuators) and the swing head 1 are installed and fixed at the upper end of the main frame 5. A weight-bearing base plate 10 is installed at the lower end of the main frame 5, and the components are fixed to the base plate 10 by bolts. A connector is installed at one end of the dynamic submarine cable 6 and connects to the bottom force-saving pulley group 804. Since the test requires the center of the swing head 1 of the test machine to be subjected to a vertically downward tension, and its force transmission path is a downwardly extending triangular truss support structure, the topology-optimized main frame 5 is composed of a triangular truss structure, with an overall tower shape, which achieves the purpose of reducing weight while ensuring safety.

[0063] The hydraulic actuators provide power for the reciprocating oscillation of the swing head 1 and the longitudinal tensile loading of the dynamic submarine cable 6. The hydraulic power is used to simulate the bending and tensile loads applied to the dynamic submarine cable 6 by the marine environment.

[0064] The anti-bend device 4 is a three-section structure made of polyurethane and epoxy resin. Its main function is to prevent excessive curvature of the dynamic submarine cable 6. The alternating stress is greatest at the upper connection point of the dynamic submarine cable 6, making it most susceptible to fatigue failure. Therefore, the anti-bend device 4 needs to be installed at the end of the dynamic submarine cable 6 to protect it by limiting its curvature.

[0065] The dynamic submarine cable 6 has a multi-layer spiral wound composite structure, and its materials are composed of steel, copper, polyethylene, polypropylene and polytetrafluoroethylene.

[0066] The experimental setup's information monitoring system includes sensors, cameras, and related data analysis software. Test data is collected and transmitted via strain gauges and sensors on the surface of the dynamic submarine cable 6 to analyze the stress and fatigue failure of the cable. The entire experimental setup and process are recorded by cameras for detailed analysis after the test.

[0067] The test equipment was installed, and it was necessary to ensure that the dynamic submarine cable 6 was in a vertical state.

[0068] The sensors and strain gauges were attached at equal intervals to the dynamic submarine cable 6;

[0069] Assemble the test apparatus and sensors, and inspect and debug the fatigue testing apparatus: apply a small-amplitude load to the swing head 1 and the tensile device using the hydraulic actuator. Record the strain data curves. After completing the above requirements, the following tests can be carried out:

[0070] 1. Drive the bending actuator 107 to drive the pendulum head 1 to reciprocate by 30° to the left and 30° to the right, and at the same time drive the tension actuator 11 to apply tension to make the dynamic submarine cable 6 bear a tensile force of 60 tons, and conduct a fatigue test on the dynamic submarine cable 6.

[0071] 2. Control the bending actuator 107 to keep the pendulum head 1 vertical, drive the tension actuator 11 to apply a tensile force of 60 tons to the dynamic submarine cable 6, and conduct a tensile test on the dynamic submarine cable 6.

[0072] During the aforementioned experiments, the entire deformation process of the dynamic submarine cable 6 was recorded using a camera. Data was transmitted to a computer via sensors and strain gauges, and the records were analyzed using data analysis software. Finally, by comparing the theoretical calculations and the software calculations, the fatigue strength and life limit of the dynamic submarine cable 6 were obtained.

[0073] Example 1

[0074] like Figures 1-4 As shown, a dynamic submarine cable vertical fatigue test device based on a topology optimization design framework includes: a vertical fatigue testing machine, which is composed of a swing head 1, a main frame 5, and a dynamic submarine cable 6.

[0075] One end of the main frame 5 is connected to the swing head 1 via the bearing 2 fixed on the bearing seat 3, and the other end is connected to the base plate 10 via four rows of second bolt holes 1002 and four rows of third bolt holes 1003. The base plate 10 is connected to the support frame 9 via bolts in the first bolt hole 1001. The support frame 9 is equipped with a sliding connecting hinge 8. The connecting hinge 8 is connected to the dynamic submarine cable 6 via a submarine cable fixer 7 above it, and to the tension actuator 11 via a force-saving pulley block 804 below it. The open-type steel truss structure (main frame 5) used in the welding assembly has good stability and saves materials. Cameras are installed at the upper and lower ends of the main frame 5 to record the real-time working conditions and changes of the dynamic submarine cable 6 and the fatigue testing machine.

[0076] The swing head 1 is mainly composed of a solid frame structure and is connected to the main frame 5 via bearings 2 and bearing seats 3. The cover plate 101 at the upper end of the swing head 1 is fixed to the swing head 1 by four screws 102. Installation and removal of the dynamic submarine cable 6 can be achieved by opening the cover plate 101. The bending mechanisms at both ends of the swing head 1 are composed of a rack and pinion mechanism. The rack 106 in the rack and pinion mechanism is connected to the connecting rod 104 via a second bolt 105. The connecting rod 104 is then connected to the swing head 1 via a first bolt 103. The lower end of the rack and pinion mechanism is fixed to the upper plate of the main frame 5 by screws. An anti-bend device 4 is installed on the dynamic submarine cable 6 connected to the swing head 1. The anti-bend device 4 protects the dynamic submarine cable 6 by limiting its curvature.

[0077] The base plate 10 is fixedly mounted on the main frame 5 and the support frame 9 via bolts in the first bolt hole 1001, the second bolt hole 1002, and the third bolt hole 1003. The axial displacement of the dynamic submarine cable 6 is controlled by a lifting platform 803 on the support frame 9. The hinge support 802 is fixedly connected to the hinge 8 via bolts in the hinge hole 801. The hinge 8 transmits tension to the dynamic submarine cable 6. A pulley block 804 is installed under the hinge 8. The tension actuator 11 is connected to a steel wire rope at one end of the pulley block 804. The tension actuator 11 controls the pulley block 804 to achieve the displacement movement of the hinge 8, thereby achieving the tensile loading of the dynamic submarine cable 6. Simultaneously, the pulley block 804 can compensate for the minute displacement generated at the end of the dynamic submarine cable 6 when the swing head 1 oscillates. The labor-saving pulley block 804 consists of two pulleys and a steel wire rope. One end of the steel wire rope is fixedly connected to the lower pulley and wound around the two pulleys, while the other end is connected to the tension actuator 11. The upper pulley is connected to the lifting platform 803, and the lower pulley is connected to the base plate 10.

[0078] A method for conducting dynamic vertical fatigue tests on submarine cables using the aforementioned testing apparatus includes the following steps:

[0079] Assemble the above parts and mechanisms to obtain the test device. Connect the bending actuator 107 and the support frame 9 to the upper plate and the bottom plate 10 respectively. At the same time, turn off the switches of each actuator. Adjust the corresponding actuator according to the motion mode required for each test. The upper section of the dynamic submarine cable 6 is fixed to the swing head 1 through the clamping mechanism, and the lower end is connected to the tension actuator 11 through the connecting hinge 8. The tension actuator 11 is then adjusted in direction by the force-saving pulley group 804 to ensure that the dynamic submarine cable 6 is in a vertical state.

[0080] Due to the test requirements, the sensors and strain gauges need to be pasted at equal intervals on the surface of the dynamic submarine cable 6, and the velocity sensor needs to be installed at the connection between the dynamic submarine cable 6 and the swing head 1 and the tension actuator 11. Finally, it is necessary to ensure that each sensor is pasted and installed firmly to prevent the sensors from falling off during the test, which would affect the acquisition of test data.

[0081] After installing the above sensors and strain gauges, the test equipment needs to be preliminarily debugged: apply small-amplitude loads to the dynamic submarine cable 6 using the bending actuator 107 and the tension actuator 11 respectively, observe the sensor recordings, and start the test once the test requirements are met.

[0082] By controlling the movement of the bending actuator 107, the oscillating head 1 begins to rotate, simultaneously causing the dynamic submarine cable 6 to swing left and right, ultimately completing the bending load on the dynamic submarine cable 6. By controlling the extension and retraction of the bending actuator 107 to control the left and right swing of the dynamic submarine cable 6, the in-situ working environment of the dynamic submarine cable 6 under the influence of ocean currents is simulated.

[0083] The tension actuator 11 controls the movement of the connecting hinge 8 by pulling the rope of the force-saving pulley block 804, thereby driving the dynamic submarine cable 6 to achieve axial loading of fixed tension.

[0084] Based on the experimental requirements, experiments can be broadly categorized into two types:

[0085] The first type is a fatigue test. First, the tension actuator 11 and the bending actuator 107 are driven, which in turn drive the dynamic submarine cable 6 to perform tensile loading and bending swing, and finally make the dynamic submarine cable 6 bear tensile and bending loads.

[0086] The second type is the tensile test. First, only the tensile actuator 11 is moved, which drives the dynamic submarine cable 6 to perform tensile movement, and finally makes the dynamic submarine cable 6 bear tensile load.

[0087] In the above experiment, the camera located on the main frame 5 will capture the entire deformation process of the dynamic submarine cable 6. At the same time, the data collected by the sensors and strain gauges will be analyzed and processed by relevant software. Finally, the results will be compared with the theoretical calculation results, and the stress condition and lifespan of the dynamic submarine cable 6 will be obtained by combining the two results.

[0088] Each of the above experiments can be repeated multiple times to reduce error.

[0089] This invention enables precise control of a hydraulic actuator system through a self-programmed program, thereby simulating ocean currents and wave movements in a marine environment. Simultaneously, it records motion output data, facilitating error adjustments to ensure motion accuracy.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dynamic submarine cable vertical fatigue testing device based on a topology optimization design framework, characterized in that, include: The structure includes a swing head (1), a main frame (5), a dynamic submarine cable (6), a connecting hinge (8), a support frame (9), a base plate (10), and a tension actuator (11). The swing head (1) is installed on the upper plate at the top of the main frame (5). The main frame (5), the support frame (9), and the tension actuator (11) are all installed on the base plate (10). The dynamic submarine cable (6) is placed vertically in the internal space of the main frame (5). The upper end of the dynamic submarine cable (6) is connected to the swing head (1) through a clamping mechanism. Each of the left and right ends of the swing head (1) is connected to a bending actuator (107). The bending actuator (107) is connected to the upper plate to realize the reciprocating swing of the swing head (1), thereby realizing the bending load on the dynamic submarine cable (6). The lower end of the dynamic submarine cable (6) is connected to the connecting hinge (8), which is slidably connected to the support frame (9). The tension actuator (11) is connected to the connecting hinge (8) to realize the displacement movement of the connecting hinge (8), thereby realizing the tension loading on the dynamic submarine cable (6). The upper part of the connecting hinge (8) is connected to the lower end of the dynamic submarine cable (6) via a submarine cable fixing device (7). The connecting hinge (8) includes a hinge hole (801), a hinge support (802), a lifting platform (803), and a force-saving pulley system (804). The lifting platform (803) is slidably connected to the support frame (9). The hinge support (802) is fixed to the lifting platform (803). The hinge hole (801) is opened on the hinge support (802). The hinge hole (801) is connected to the submarine cable fixing device (7) by the bolts that are internally fitted. The lower part of the lifting platform (803) is connected to the labor-saving pulley group (804). The labor-saving pulley group (804) consists of two pulleys and a steel wire rope. One end of the steel wire rope is fixedly connected to the lower pulley and wound around the two pulleys. The other end is connected to the tension actuator (11). The upper pulley is connected to the lifting platform (803), and the lower pulley is connected to the base plate (10). The tension actuator (11) controls the force-saving pulley group (804) to realize the displacement movement of the connecting hinge (8), thereby realizing the tension loading of the dynamic submarine cable (6); at the same time, the force-saving pulley group (804) is used to compensate for the small displacement generated at the end of the dynamic submarine cable (6) when the swing head (1) swings. The main frame (5) is welded from open-type steel and is composed of a triangular truss structure. The whole structure is tower-shaped and forms a triangular truss support structure. The lower end of the main frame (5) has multiple rows of second bolt holes (1002) and multiple rows of third bolt holes (1003). Bolts are connected in both the second bolt holes (1002) and the third bolt holes (1003). The main frame (5) is connected to the base plate (10) through the second bolt holes (1002), the third bolt holes (1003) and the bolts. The lower end of the support frame (9) has a first bolt hole (1001). The support frame (9) is connected to the base plate (10) through the bolts connected in the first bolt hole (1001).

2. The dynamic submarine cable vertical fatigue test device based on topology optimization design framework according to claim 1, characterized in that, The swing head (1) adopts a solid frame structure and is connected to the bending actuator (107) through a bending mechanism. The bending actuator (107) is connected to the hinge support on the main frame (5).

3. The dynamic submarine cable vertical fatigue test device based on topology optimization design framework according to claim 2, characterized in that, The bending mechanism includes a connecting rod (104) and a gear and rack mechanism. The gear and rack mechanism includes at least a gear and a rack (106). One end of the connecting rod (104) is connected to the swing head (1) by a first bolt (103), and the other end is connected to the rack (106) by a second bolt (105). The rack (106) is meshed with the gear for transmission. The gear is connected to the bending actuator (107). The lower end of the rack and gear mechanism is fixed to the upper plate of the main frame (5) by a screw connection.

4. The dynamic submarine cable vertical fatigue test device based on topology optimization design framework according to claim 1, characterized in that, The swing head (1) is connected to the main frame (5) by a shaft. The upper plate of the main frame (5) is welded with a bearing seat (3), and a bearing (2) is installed in the bearing seat (3). The bearing (2) is connected to the shaft of the swing head (1). The upper end of the swing head (1) is provided with a cover plate (101), which is fixed to the swing head (1) by multiple screws (102). When installing and removing the dynamic submarine cable (6), the cover plate (101) is opened.

5. The dynamic submarine cable vertical fatigue test device based on topology optimization design framework according to claim 1, characterized in that, An anti-bend device (4) is installed at the connection between the dynamic submarine cable (6) and the swing head (1). The anti-bend device (4) is a three-section structure made of polyurethane and epoxy resin.

6. The dynamic submarine cable vertical fatigue test device based on topology optimization design framework according to claim 1, characterized in that, Both the bending actuator (107) and the stretching actuator (11) are hydraulic actuators.

7. The dynamic submarine cable vertical fatigue test device based on topology optimization design framework according to claim 1, characterized in that, It also includes an information monitoring system, which includes at least sensors, cameras and data analysis software. The sensors are installed on the surface of the dynamic submarine cable (6), and strain gauges are also installed on the surface of the dynamic submarine cable (6). The sensors and strain gauges are attached to the dynamic submarine cable (6) at equal distances and are electrically connected to the host computer. The test data is collected and transmitted to the host computer through the strain gauges and sensors. The data analysis software is used to analyze the stress and fatigue failure of the dynamic submarine cable (6). The sensors are installed at the upper and lower ends of the main frame (5) and the camera records the real-time working conditions and changes of the dynamic submarine cable (6) and the fatigue testing machine.

8. A test method for a dynamic submarine cable vertical fatigue test device based on a topology optimization design framework as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Assemble the various parts and mechanisms to obtain the test device. Connect the bending actuator (107) and the support frame (9) to the upper plate and the bottom plate (10) of the main frame (5) respectively. At the same time, turn off the switches of each actuator. Adjust the corresponding actuator according to the motion mode required for each test. The upper section of the dynamic submarine cable (6) is fixed on the swing head (1) through the clamping mechanism, and the lower end is connected to the tension actuator (11) through the connecting hinge (8). The tension actuator (11) is adjusted in direction by the force-saving pulley group (804) to ensure that the dynamic submarine cable (6) is in a vertical state. S2. Based on the test requirements, the sensors and strain gauges are attached to the surface of the dynamic submarine cable (6) at equal distances. The sensors are installed at the connection between the dynamic submarine cable (6) and the swing head (1) and the tension actuator (11). Finally, it is determined whether each sensor is attached and installed firmly to prevent the sensors from falling off during the test, which would affect the acquisition of test data. S3. After installing the above sensors and strain gauges, perform preliminary debugging of the testing device: apply small-amplitude loads to the dynamic submarine cable (6) using the bending actuator (107) and the tension actuator (11) respectively, observe the sensor recording, and start the test once the test requirements are met. S4. Control the movement of the bending actuator (107), the swing head (1) starts to swing, and at the same time drives the dynamic submarine cable (6) to swing left and right, and finally completes the bending load on the dynamic submarine cable (6); by controlling the extension and retraction of the bending actuator (107) to control the left and right swing of the dynamic submarine cable (6), the in-situ working environment of the dynamic submarine cable (6) under the ocean current is simulated. S5, the tension actuator (11) controls the movement of the connecting hinge (8) by pulling the steel wire rope of the force-saving pulley block (804), thereby driving the dynamic submarine cable (6) to achieve axial loading of fixed tension; Based on the experimental requirements, there are two types of experiments: The first type is a fatigue test. First, the tension actuator (11) and the bending actuator (107) are driven, which in turn drive the dynamic submarine cable (6) to perform tensile loading and bending swing, and finally make the dynamic submarine cable (6) bear tensile and bending loads. The second type is the tensile test. First, only the tensile actuator (11) is allowed to move, which then drives the dynamic submarine cable (6) to perform tensile movements, and finally makes the dynamic submarine cable (6) bear the tensile load. In the above experiment, the camera located on the main frame (5) captured the entire deformation process of the dynamic submarine cable (6). At the same time, the data collected by the sensor and strain gauge were analyzed and processed by relevant software. Finally, the theoretical calculation results were compared and the two results were combined to obtain the stress condition and life calculation of the dynamic submarine cable (6). Each of the above experiments can be repeated multiple times to reduce error.

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