Carbon fiber composite mooring line performance test device and test method

Abstract

A performance testing device and method for carbon fiber composite mooring cables includes a floating structure and one or more sets of mooring cable assemblies. Each set of mooring cables includes a first winch and a second winch, a first cable guide hole and a second cable guide hole, all located on the upper part of the floating structure. A first synthetic fiber cable is connected to the first winch, and a second synthetic fiber cable is connected to the second winch. The device also includes an anchoring foundation on the seabed, a water drum floating on the water surface, and an anchor chain assembly. The lower end of the anchor chain assembly is connected to the anchoring foundation, and the upper end is equipped with a water drum and a three-eye plate. The lower end of the first synthetic fiber cable passes through the first cable guide hole and connects to the three-eye plate. The lower end of the second synthetic fiber cable passes through the second cable guide hole and connects to the upper end of the carbon fiber composite mooring cable to be tested. The lower end of the carbon fiber composite mooring cable is connected to the three-eye plate. This device enables performance testing of the carbon fiber composite mooring cable in a marine environment. The testing process is safe and controllable, and the testing method is scientific, comprehensive, simple, and feasible.

Description

Technical Field

[0001] This invention relates to the field of marine engineering technology, and in particular to a testing device and method for testing the performance of carbon fiber composite mooring cables. Background Technology

[0002] Carbon fiber composite mooring cables represent an innovative technology for mooring and positioning floating structures. They combine the lightweight and high-strength properties of carbon fiber composites with the crucial role of mooring cables in ships and offshore structures, bringing numerous new possibilities to the field of marine engineering. Carbon fiber composites possess high strength and high modulus, exhibiting higher strength per unit mass compared to traditional metal mooring chains and cables, thus avoiding the need for additional buoyancy to balance the wet weight of the cable. Compared to synthetic fiber mooring cables, they offer higher elastic modulus, length stability, and abrasion resistance.

[0003] As a novel material, although it has already been used in some bridge cables, in the marine environment, it is subject to continuous structural damage and destruction caused by external forces such as wind, waves, and currents, as well as corrosion from seawater. Many unknown factors and problems arise when it is put into practical marine engineering applications. Sea trials are necessary to examine its actual behavior and provide experience and guidance for subsequent engineering projects. This is crucial for mooring systems that need to withstand cyclic loads at sea for extended periods. Furthermore, hastily using carbon fiber composite mooring cables for platform mooring and positioning at sea could lead to serious consequences such as platform drift or even collisions if the cables break. Currently, there is no testing equipment or method available to test the performance of carbon fiber composite mooring cables in a marine environment. Summary of the Invention

[0004] In response to the shortcomings of the existing production technology, the applicant provides a carbon fiber composite mooring cable performance testing device and method, thereby realizing the performance testing of carbon fiber composite mooring cables in marine environments. The testing process is safe and controllable, and the testing method is scientific, comprehensive, simple and feasible.

[0005] The technical solution adopted in this invention is as follows:

[0006] A carbon fiber composite mooring cable performance testing device includes a floating structure and one or more sets of mooring cables for mooring the floating structure, with each set of mooring cables corresponding to a mooring point.

[0007] A set of mooring cables includes a first winch and a second winch disposed on the upper part of the floating structure. The side of the floating structure is provided with a first cable guide hole and a second cable guide hole. The first cable guide hole matches the first winch, and the second cable guide hole matches the second winch.

[0008] The first winch is connected to a first synthetic fiber cable, and the second winch is connected to a second synthetic fiber cable;

[0009] It also includes an anchoring foundation submerged on the seabed, a water drum floating on the water surface, and an anchor chain assembly. The lower end of the anchor chain assembly is connected to the anchoring foundation, the upper end of the anchor chain assembly is provided with the water drum, and the upper end of the anchor chain assembly is equipped with a three-eyed plate.

[0010] The lower end of the first synthetic fiber cable passes through the first cable guide hole and is connected to the three-eye plate. The lower end of the second synthetic fiber cable passes through the second cable guide hole and is connected to the upper end of the carbon fiber composite mooring cable to be tested. The lower end of the carbon fiber composite mooring cable is connected to the three-eye plate.

[0011] Its further technical solution lies in:

[0012] The lower end of the first synthetic fiber cable is provided with a first shackle by means of insertion and braiding, and the first shackle is connected to the three-eye plate;

[0013] The lower end of the second synthetic fiber cable is provided with a second shackle by means of insertion and braiding, and the second shackle is connected to the upper end of the carbon fiber composite mooring cable.

[0014] The surface of the first synthetic fiber cable is provided with buoyancy material.

[0015] The cross-section of the carbon fiber composite mooring cable is circular. The carbon fiber composite mooring cable includes multiple conventional carbon fiber rods and multiple measuring carbon fiber rods. The conventional carbon fiber rods and measuring carbon fiber rods are assembled to form a carbon fiber bundle. One measuring carbon fiber rod is located at the center of the carbon fiber bundle, and the remaining measuring carbon fiber rods are evenly distributed in a ring array with the center of the carbon fiber bundle as the center.

[0016] The structure of a single measuring carbon fiber rod includes an optical fiber sensor whose length is adapted to the length of the carbon fiber composite mooring cable, and the outside of the optical fiber sensor is wrapped with carbon fiber filaments.

[0017] The upper end of the carbon fiber composite mooring cable is provided with a third shackle, and the lower end of the carbon fiber composite mooring cable is provided with a fourth shackle. The third shackle is connected to the first synthetic fiber cable, and the fourth shackle is connected to the second synthetic fiber cable.

[0018] A test method for the performance of carbon fiber composite mooring cables.

[0019] Step 1: Establish test evaluation indicators for the marine application of carbon fiber composite mooring cables. The test evaluation indicators include mooring system adaptability, mooring cable strength, maximum tension of mooring cable, mooring cable morphology, mooring cable fatigue life, mooring cable wear resistance, mooring cable corrosion resistance, and mooring cable reliability.

[0020] Step 2: Design the test plan based on the test evaluation indicators;

[0021] Step 3: Prepare the equipment and instruments for the test, including a carbon fiber composite mooring cable performance testing device as described in claim 1, and a data acquisition system;

[0022] Step 4: Analyze and determine the position and length of the carbon fiber composite mooring cable to be tested relative to the floating structure;

[0023] Step 5: Multiple fiber optic sensors are embedded in the fiber bundle of the carbon fiber composite mooring cable. The fiber optic sensors are arranged along the length of the carbon fiber composite mooring cable, and the length of the fiber optic sensors is adapted to the length of the carbon fiber composite mooring cable. A carbon fiber composite mooring cable performance testing device is set up to form a test mooring system. The carbon fiber composite mooring cable to be tested is installed. The fiber optic sensors are connected to the data acquisition system. At this time, the carbon fiber composite mooring cable is suspended and has no pretension, and the first synthetic fiber cable is in a tensioned state.

[0024] Step Six: Apply load to the carbon fiber composite mooring cable until it fully bears the mooring force in the corresponding direction.

[0025] After the carbon fiber composite mooring cable is loaded, the experimental mooring system can be put into sea trial.

[0026] Step Seven: Experimental Observation:

[0027] During the sea trial, dynamic data was monitored, including six-degree-of-freedom motion performance, maximum tension, cable morphology, and current surface condition of the cable. The dynamic data was recorded in the data acquisition system.

[0028] Static data were measured, including cable strength, as well as observational data on the corrosion surface morphology and composition of the carbon fiber composite mooring cable after sea trials.

[0029] Step 8: Analyze the test data: Evaluate and analyze the performance of the carbon fiber composite mooring cable based on dynamic and static data;

[0030] Step Nine: Results Evaluation and Summary.

[0031] Its further technical solution lies in:

[0032] Step six involves the following loading methods for the carbon fiber composite mooring cable:

[0033] The second winch is started to gradually tighten the second synthetic fiber cable, so that the carbon fiber composite mooring cable gradually bears the tension. When the overall shape of the second synthetic fiber cable and the carbon fiber composite mooring cable is the same as that of the first synthetic fiber cable, the first winch is started to release the first synthetic fiber cable, so that the first synthetic fiber cable is in a relaxed state. The first synthetic fiber cable floats on the sea surface under the action of its external buoyancy material, so that the carbon fiber composite mooring cable can bear the mooring tension completely independently.

[0034] The test plan in step two includes measurements of the maximum tension and morphology of the mooring cable, and the measurement methods include:

[0035] During sea trials, single fiber optic sensors monitored the tensile force on the carbon fiber composite mooring cable in real time as the cable was subjected to stress and deformation.

[0036] The strain state of the carbon fiber composite mooring cable on different sides is obtained by analyzing the optical path difference of multiple optical fiber sensors when the carbon fiber composite mooring cable is subjected to stress and deformation, and thus the morphology of the carbon fiber composite mooring cable is obtained.

[0037] In step seven, the data acquisition system analyzes and processes the obtained tension data and optical path difference data to obtain the maximum tension and cable shape.

[0038] During sea trials of the mooring system, the time it took for the carbon fiber composite mooring cable to fracture was recorded as its fatigue life.

[0039] At this point, the first synthetic fiber cable corresponding to the broken carbon fiber composite mooring cable takes on a mooring function.

[0040] A strain sensor for measuring the tension of the first synthetic fiber cable 31 is provided on the first synthetic fiber cable 31.

[0041] The beneficial effects of this invention are as follows:

[0042] This invention features a compact and reasonable structure, and is easy to operate. Based on the characteristics of carbon fiber composite mooring cables, it partially replaces traditional mooring cables with carbon fiber composite mooring cables on the basis of conventional mooring and positioning structures. Two sets of mooring cable structures that can be tightened and loosened are set at the same mooring point, which facilitates the installation of the carbon fiber composite mooring cable to be tested and ensures the safety of the test process. This enables the performance testing of carbon fiber composite mooring cables in marine environments. The test process is safe and controllable, and the test method is scientific, comprehensive, simple and feasible.

[0043] By establishing comprehensive test evaluation indicators, and primarily by replacing parts of the mooring system using traditional mooring cables with carbon fiber composite mooring cables, a test method for the application of carbon fiber composite mooring cables in a marine field mooring system was proposed for the first time. During the process of ensuring safe mooring and positioning, the original mooring cables that met the mooring requirements were gradually replaced, until finally the carbon fiber composite mooring cables bore the tension of the replaced mooring cables entirely. Dynamic and static data were observed throughout the entire test period based on the test evaluation indicators to obtain comprehensive test data for evaluating the engineering application of carbon fiber composite mooring cables. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of the present invention.

[0045] Figure 2 for Figure 1 Enlarged view of point A in the middle.

[0046] Figure 3 This is a schematic diagram of the structure of the carbon fiber composite mooring cable of the present invention.

[0047] Figure 4 This is a flowchart of the test method of the present invention.

[0048] The components include: 1. Floating structure; 21. First winch; 210. First cable guide hole; 22. Second winch; 220. Second cable guide hole; 31. First synthetic fiber cable; 32. Second synthetic fiber cable; 4. Carbon fiber composite mooring cable; 401. Conventional carbon fiber rod; 402. Measuring carbon fiber rod; 403. Sheath; 400. Fiber optic sensor; 5. Three-eye plate; 6. Water drum; 7. Anchor chain assembly; 8. Anchoring foundation. Detailed Implementation

[0049] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0050] Example 1:

[0051] like Figure 1 , Figure 2 As shown, the carbon fiber composite mooring cable performance testing device of this embodiment includes a floating structure 1 and one or more sets of mooring cables for mooring the floating structure 1, with each set of mooring cables corresponding to a mooring point.

[0052] A set of mooring cables includes a first winch 21 and a second winch 22 disposed on the upper part of the floating structure 1. A first cable guide hole 210 and a second cable guide hole 220 are provided on the side of the floating structure 1. The first cable guide hole 210 matches the first winch 21, and the second cable guide hole 220 matches the second winch 22.

[0053] The first winch 21 is connected to the first synthetic fiber cable 31, and the second winch 22 is connected to the second synthetic fiber cable 32.

[0054] It also includes an anchoring foundation 8 submerged on the seabed, a water drum 6 floating on the water surface, and an anchor chain assembly 7. The lower end of the anchor chain assembly 7 is connected to the anchoring foundation 8, the upper end of the anchor chain assembly 7 is provided with the water drum 6, and the upper end of the anchor chain assembly 7 is equipped with a three-eye plate 5.

[0055] The lower end of the first synthetic fiber cable 31 passes through the first cable guide hole 210 and is connected to the three-eye plate 5. The lower end of the second synthetic fiber cable 32 passes through the second cable guide hole 220 and is connected to the upper end of the carbon fiber composite mooring cable 4 to be tested. The lower end of the carbon fiber composite mooring cable 4 is connected to the three-eye plate 5.

[0056] The water drum 6 is used to lift one end of the anchor chain assembly 7 out of the water surface, so as to facilitate the connection and fixation of the carbon fiber composite mooring cable 4 during the test.

[0057] The carbon fiber composite mooring cable 4 was used as the test object. Before the test, the upper end of the carbon fiber composite mooring cable 4 was connected to the second synthetic fiber cable 32, the lower end of the carbon fiber composite mooring cable 4 was connected to the three-eye plate 5, and the carbon fiber composite mooring cable 4 was indirectly connected to the second winch 22 to avoid large bending deformation of the carbon fiber composite mooring cable 4 and to prevent the carbon fiber composite mooring cable 4 from breaking by avoiding the second guide hole 220.

[0058] The first winch 21 is used to control the length of the first synthetic fiber cable 31. Before the installation of the carbon fiber composite mooring cable 4, the first synthetic fiber cable 31 is used for mooring the floating structure 1. After the carbon fiber composite mooring cable 4 is installed and tightened, when the overall shape of the second synthetic fiber cable 32 and the carbon fiber composite mooring cable 4 is the same as the configuration of the first synthetic fiber cable 31, the first synthetic fiber cable 31 is appropriately loosened. At this time, the first synthetic fiber cable 31 becomes the mooring cable to be replaced.

[0059] The second winch 22 is used to control the length of the second synthetic fiber cable 32 and to apply tension to the carbon fiber composite mooring cable 4 after tightening the second synthetic fiber cable 32.

[0060] In the event of a failure of the carbon fiber composite mooring cable 4 in a certain group of mooring cables, the previously replaced mooring cable, namely the corresponding first synthetic fiber cable 31, can still moor the floating structure 1, ensuring the safety of the mooring system during the test. The specific number of mooring cable groups depends on whether the mooring system is single-point or multi-point mooring.

[0061] The floating structure 1 can be a semi-submersible platform with a small waterline area, resulting in a smaller motion response in waves, which is beneficial for the work and life of the test personnel.

[0062] Both the first synthetic fiber cable 31 and the second synthetic fiber cable 32 are made of high-strength polyethylene.

[0063] The anchor chain assembly 7 includes two connected anchor chains. The bottom is a thicker anchor chain, and the top is an R3S grade anchor chain with a high strength per unit area. That is, the bottom has a higher wet weight, while the top is lightweight.

[0064] Anchoring foundation 8 is used to connect and secure one end of anchor chain assembly 7, providing final restraint for the entire mooring system.

[0065] The carbon fiber composite mooring cable performance testing device of this embodiment, based on the conventional mooring positioning structure and considering the characteristics of the carbon fiber composite mooring cable 4, partially replaces the traditional mooring cable with the carbon fiber composite mooring cable 4, and sets up two sets of mooring cable structures that can be stretched and loosened at the same mooring point. This facilitates the installation of the carbon fiber composite mooring cable 4 to be tested and also ensures the safety of the test process. Thus, it realizes the performance testing of the carbon fiber composite mooring cable in the marine environment. The test process is safe and controllable, and the test method is scientific, comprehensive, simple and feasible.

[0066] Furthermore, the lower end of the first synthetic fiber cable 31 is provided with a first shackle by means of insertion and braiding, and the first shackle is connected to the three-eye plate 5;

[0067] The lower end of the second synthetic fiber cable 32 is provided with a second shackle by means of insertion and braiding, and the second shackle is connected to the upper end of the carbon fiber composite mooring cable 4.

[0068] Furthermore, the surface of the first synthetic fiber cable 31 is provided with a buoyancy material. The buoyancy material is tied to the section of the first synthetic fiber cable 31 that is floating at sea, so that the first synthetic fiber cable 31 can float on the sea surface.

[0069] Furthermore, such as Figure 3 As shown, the cross-section of the carbon fiber composite mooring cable 4 is circular. The carbon fiber composite mooring cable 4 includes multiple conventional carbon fiber rods 401 and multiple measuring carbon fiber rods 402. The conventional carbon fiber rods 401 and the measuring carbon fiber rods 402 are assembled to form a carbon fiber bundle. One measuring carbon fiber rod 402 is located at the center of the carbon fiber bundle, and the remaining measuring carbon fiber rods 402 are evenly distributed in a ring array with the center of the carbon fiber bundle as the center.

[0070] The structure of a single measuring carbon fiber rod 402 includes an optical fiber sensor 400, the length of which is adapted to the length of the carbon fiber composite mooring cable 4, and the optical fiber sensor 400 is wrapped with carbon fiber filaments.

[0071] Specifically, the conventional carbon fiber rod 401 and the measuring carbon fiber rod 402 have similar external structures. The measuring carbon fiber rod 402 is formed by wrapping carbon fiber filaments around the fiber optic sensor 400. The specific forming method is that the fiber optic sensor 400 is pre-embedded in the carbon fiber filaments during the stretching and pressing of the carbon fiber filaments, and then the measuring carbon fiber rod 402 is formed by resin casting.

[0072] The gaps in the carbon fiber bundle formed by the conventional carbon fiber rod 401 and the measuring carbon fiber rod 402 are filled with epoxy resin matrix, and the outer periphery of the carbon fiber bundle is wrapped with a sheath 403.

[0073] The number of carbon fiber rods 402 is greater than or equal to five. When the carbon fiber composite mooring cable 4 is subjected to force and deformation, a single fiber optic sensor 400 monitors the tension on the carbon fiber composite mooring cable 4 in real time, and uniformly measures the tension at different positions of the cross section of the carbon fiber composite mooring cable 4. The multiple fiber optic sensors 400 measure the tension to verify each other and ensure that the test can continue normally even if one fiber optic sensor 400 fails. At the same time, multiple fiber optic sensors 400 can also measure the deformation of the carbon fiber composite mooring cable 4 in different directions. By analyzing the optical path difference of multiple fiber optic sensors 400, the strain state of different sides of the carbon fiber composite mooring cable 4 can be obtained, and thus the morphology of the carbon fiber composite mooring cable 4 can be obtained. This method is existing technology and will not be described in detail here.

[0074] Of course, when the carbon fiber composite mooring cable 4 is moored, the fiber optic sensor 400 measures the tension on the carbon fiber composite mooring cable 4. Alternatively, a strain sensor can be installed on the first shackle at the lower end of the first synthetic fiber cable 31 to measure the tension on the first synthetic fiber cable 31 when it is moored.

[0075] Multiple fiber optic sensors 400 are pre-embedded inside the carbon fiber composite mooring cable 4, so that the state of the fiber optic sensors 400 changes with the state of the carbon fiber composite mooring cable 4 at all times. This enables the measurement of the force at any point along the length of the carbon fiber composite mooring cable 4, and improves the accuracy of the tension and shape measurement of the carbon fiber composite mooring cable 4.

[0076] Furthermore, such as Figure 2 As shown, the upper end of the carbon fiber composite mooring cable 4 is provided with a third shackle, and the lower end of the carbon fiber composite mooring cable 4 is provided with a fourth shackle. The third shackle is connected to the first synthetic fiber cable 31, and the fourth shackle is connected to the second synthetic fiber cable 32.

[0077] In the above cable and rope connection structure, one eye ring of the three-eye plate 5 is connected to the upper end of the anchor chain assembly 7 through a shackle, and one of the other two rings is connected to the first shackle to connect the first synthetic fiber cable 31. The other ring is reserved for the test object - the carbon fiber composite mooring cable 4. When installing the carbon fiber composite mooring cable 4, the third shackle is connected to the three-eye plate 5, and the fourth shackle is connected to the second shackle.

[0078] like Figure 1 As shown in the figure, the carbon fiber composite mooring cable performance testing device of this embodiment has a floating structure 1 floating on the sea surface, which is moored and positioned by four sets of mooring cables. Based on the special design and installation stress method of each set of cables, a sea testing space can be provided for the carbon fiber composite mooring cable 4. Specifically, the installation and use method of this testing device is as follows:

[0079] The anchoring foundation 8, which is connected to the anchor chain assembly 7, is placed in the sea area around the floating structure 1. At the same time, the water drum 6 is strung on the light chain end of the anchor chain assembly 7 and the light chain end of the anchor chain assembly 7 is lifted out of the water.

[0080] The first winch 21 is connected to the first synthetic fiber cable 31. The lower end of the first synthetic fiber cable 31 extends into the sea through the first cable guide hole 210 and is fixed to the first shackle. It is further connected to the three-eye plate 5 through the first shackle. One eye of the three-eye plate 5 is connected to the light chain end of the anchor chain assembly 7 through the shackle, leaving one eye for later use.

[0081] After selecting the test plan, the mooring cable group to be operated is connected as follows: the second winch 22 is connected to the second synthetic fiber cable 32, the lower end of the second synthetic fiber cable 32 is connected to the second shackle by inserting and braiding, and then connected to the third shackle of the carbon fiber composite mooring cable 4 to be tested through the second shackle. The fourth shackle of the carbon fiber composite mooring cable 4 is connected to the three-eye plate 5.

[0082] After the connection is completed, the second synthetic fiber cable 32 is tightened by the second winch 22, and then the first synthetic fiber cable 31 is appropriately loosened by the first winch 21 to avoid collision or entanglement with the carbon fiber composite cable 4 and to ensure that it can be re-stressed at any time. At the same time, it ensures that the mooring and positioning capability of the test device can be supplemented by the first synthetic fiber cable 31 in case of damage to the carbon fiber composite mooring cable 4 under extreme sea conditions, which greatly improves the safety of the carbon fiber composite mooring cable sea test. It can be applied to the test and evaluation design of carbon fiber composite mooring cables deployed in open sea areas.

[0083] The carbon fiber composite mooring cable performance testing device is reusable. It can be used simply by replacing the carbon fiber composite mooring cable 4 with different grades and changing the mooring points and the number of mooring cable groups of the floating structure 1. It can achieve rapid and accurate quantitative evaluation of the dynamic characteristics of the carbon fiber composite mooring cable 4 under different mooring conditions and different grades. It is also easy to use. The anchor chain assembly 7 and water drum 6 of the existing mooring system of the testing device are easy to install and are suitable for marine testing and verification before the engineering application of carbon fiber composite mooring cables.

[0084] Example 2:

[0085] like Figure 1 , Figure 2 , Figure 4 As shown in this embodiment, the test method for the performance of carbon fiber composite mooring cables is as follows:

[0086] Step 1: Establish test evaluation indicators for the marine application of carbon fiber composite mooring cables. The test evaluation indicators include mooring system adaptability, mooring cable strength, maximum tension of mooring cable, mooring cable morphology, mooring cable fatigue life, mooring cable wear resistance, mooring cable corrosion resistance and mooring cable reliability.

[0087] Step 2: Design the test plan based on the test evaluation indicators;

[0088] Step 3: Prepare the equipment and instruments used for the test. The equipment and instruments include the carbon fiber composite mooring cable performance testing device of Example 1, as well as the data acquisition system.

[0089] Step 4: Analyze and determine the position and length of the carbon fiber composite mooring cable 4 to be tested on the floating structure 1;

[0090] Step 5: Multiple fiber optic sensors 400 are embedded in the fiber bundle of the carbon fiber composite mooring cable 4. The fiber optic sensors 400 are arranged along the length of the carbon fiber composite mooring cable 4, and the length of the fiber optic sensors 400 is adapted to the length of the carbon fiber composite mooring cable 4. The carbon fiber composite mooring cable performance testing device is set up to form a test mooring system, and the carbon fiber composite mooring cable 4 to be tested is installed. The fiber optic sensors 400 are connected to the data acquisition system. At this time, the carbon fiber composite mooring cable 4 is in a suspended state without pretension, and the first synthetic fiber cable 31 is in a tensioned state.

[0091] Step Six: Apply load to the carbon fiber composite mooring cable 4 until it fully bears the mooring force in the corresponding direction.

[0092] After the loading of the carbon fiber composite mooring cable 4 is completed, the sea trial of the experimental mooring system can be carried out.

[0093] Step Seven: Experimental Observation:

[0094] During the sea trial, dynamic data was monitored, including six-degree-of-freedom motion performance, maximum tension, cable morphology, and current surface condition of the cable. The dynamic data was recorded in the data acquisition system.

[0095] Static data were measured, including cable strength, as well as observation data on the corrosion surface morphology and composition of the carbon fiber composite mooring cable 4 after the sea trial.

[0096] Step 8: Analyze the test data: Evaluate and analyze the performance of carbon fiber composite mooring cable 4 based on dynamic and static data;

[0097] Step Nine: Results Evaluation and Summary.

[0098] The performance test method for carbon fiber composite mooring cables in this embodiment establishes comprehensive test evaluation indicators. It mainly achieves this by partially replacing the mooring system using traditional mooring cables with carbon fiber composite mooring cables 4. This is the first time that a test method for the application of carbon fiber composite mooring cables in a marine mooring system has been proposed. During the process of ensuring safe mooring and positioning, the original mooring cable that meets the mooring requirements is gradually replaced. Finally, the tension of the replaced mooring cable is completely borne by the carbon fiber composite mooring cable 4. Dynamic and static data are observed throughout the test cycle according to the test evaluation indicators to obtain comprehensive test data for the engineering application evaluation of carbon fiber composite mooring cables 4.

[0099] The carbon fiber composite mooring cable performance test method, employing the carbon fiber composite mooring cable performance test device of Example 1, ensures the safety of the mooring system in the event of a breakage of the carbon fiber composite mooring cable 4. It can examine the performance of the carbon fiber composite mooring cable under extreme sea conditions and typhoon events, evaluating and verifying the mechanical performance of the carbon fiber composite mooring cable in marine applications under extreme sea conditions. Furthermore, the test device is easy to use, with convenient installation of the existing anchor chain assembly 7 and water drum 6, making it suitable for marine testing and verification before the engineering application of carbon fiber composite mooring cables.

[0100] When testing new and unknown materials, the emergency plan in the test observation method is an important guarantee for the safety of the test. Specifically, it is used to prevent damage such as breakage of carbon fiber composite mooring cables during the sea test phase. In particular, when the end of the carbon fiber composite mooring cable fails under extreme sea conditions and cannot be replaced or remedial operations under severe sea conditions, the test platform faces a huge challenge of mooring positioning failure. The test method in this embodiment can be said to implement the test process and the emergency plan simultaneously, which has an absolute safety guarantee.

[0101] Example 3:

[0102] like Figure 1 , Figure 2 , Figure 4 As shown in this embodiment, the test method for the performance of carbon fiber composite mooring cables is as follows:

[0103] Step 1: Establish test evaluation indicators for the marine application of carbon fiber composite mooring cables. The test evaluation indicators include mooring system adaptability, mooring cable strength, maximum tension of mooring cable, mooring cable morphology, mooring cable fatigue life, mooring cable abrasion resistance, mooring cable corrosion resistance, and mooring cable reliability.

[0104] Based on experimental evaluation indicators, four relevant parameters of carbon fiber composite mooring cables were monitored at sea. The experimental evaluation indicators included those for traditional mooring cables, as well as those specifically designed for the unique material characteristics of carbon fiber composite mooring cables. For example, the mooring cable morphology refers to the configurational change of the carbon fiber composite mooring cable under stress. Unlike traditional mooring materials, carbon fiber composites cannot undergo significant bending or withstand pressure, thus requiring monitoring of the mooring cable morphology. The reliability of the mooring cable refers to its ability to maintain its function and performance under various environmental conditions, which is affected by factors such as material quality, manufacturing process, and usage conditions. This was determined through on-site observation.

[0105] Step 2: Design the test plan based on the test evaluation indicators; the test plan includes determining the purpose of the test, the test period, the test parameters, the test equipment and the test methods. Considering the characteristics and application environment of the carbon fiber composite mooring cable 4, the test conditions, the test period and the test data acquisition method are determined.

[0106] The purpose of the experiment is to test the mooring characteristics of the new material by conducting experiments on the marine application of carbon fiber composite mooring cables. The experiment period can be as short as one to two years or as long as ten years or more.

[0107] Step 3: Prepare the equipment and instruments for the test. The equipment and instruments include the carbon fiber composite mooring cable performance testing device of Example 1, as well as the data acquisition system.

[0108] This step involves preparing the equipment and instruments for the test, specifically by deploying the carbon fiber composite mooring cable performance testing device in the test sea area to form a test mooring system.

[0109] Step 4: Analyze and determine the position and length of the carbon fiber composite mooring cable 4 to be tested on the floating structure 1.

[0110] This step involves evaluating the stress conditions of each group of mooring cables at their corresponding mooring points under the current sea conditions using the carbon fiber composite mooring cable performance testing device. Based on the characteristics of the carbon fiber composite mooring cable to be tested, the location for attaching the cable is calculated, and the location to be tested and replaced is selected.

[0111] Based on the experimental capabilities of the test apparatus, actual measurement analysis and numerical simulation prediction of the mooring system were conducted to obtain the stress conditions of different mooring cables. The actual measurement analysis was based on force sensors installed on the first synthetic fiber cable 31 of each mooring cable group. The numerical simulation prediction was modeled and analyzed using potential flow theory. The results of numerical calculations and actual measurements were compared and verified to improve the accuracy of hydrodynamic coefficients and numerical predictions. This verified the accuracy of the numerical prediction method. Based on the applicability of the above numerical prediction technology on the test platform, and combined with the theoretical performance of the dynamic characteristics of the carbon fiber composite mooring cable to be tested, the installation location and length of the carbon fiber cable were determined. Simultaneously, numerical analysis of the mooring system containing the carbon fiber composite mooring cable was conducted. Through optimization calculations, suitable mooring configurations and the composition ratio of the composite cable were determined, providing a more optimized scheme for subsequent actual sea verification.

[0112] Step 5: Multiple fiber optic sensors 400 are embedded in the fiber bundle of the carbon fiber composite mooring cable 4. The fiber optic sensors 400 are arranged along the length of the carbon fiber composite mooring cable 4, and the length of the fiber optic sensors 400 is adapted to the length of the carbon fiber composite mooring cable 4. The carbon fiber composite mooring cable performance testing device is set up to form a test mooring system, and the carbon fiber composite mooring cable 4 to be tested is installed. The fiber optic sensors 400 are connected to the data acquisition system. At this time, the carbon fiber composite mooring cable 4 is suspended and in a state without pretension, and the first synthetic fiber cable 31 is in a tensioned state. According to the design requirements, the carbon fiber composite mooring cable 4 is correctly installed on the test device. It is important to ensure that the tension and angle parameters of the cable meet the test requirements.

[0113] Step Six: Apply load to the carbon fiber composite mooring cable 4 until it fully bears the mooring force in the corresponding direction.

[0114] After the loading of the carbon fiber composite mooring cable 4 is completed, the sea trial of the experimental mooring system can be carried out.

[0115] In step six, the second winch 22 is activated to gradually tighten the second synthetic fiber cable 32, causing the carbon fiber composite mooring cable 4 to gradually bear tension. Once the overall shape of the second synthetic fiber cable 32 and the carbon fiber composite mooring cable 4 is identical to that of the first synthetic fiber cable 31, the first winch 21 is activated to release the first synthetic fiber cable 31, placing it in a relaxed state. The first synthetic fiber cable 31 floats on the sea surface under the action of its external buoyancy material, allowing the carbon fiber composite mooring cable 4 to bear the mooring tension completely independently. Simultaneously, relevant data during the test are recorded, such as the loading force, displacement, and deformation of the carbon fiber composite mooring cable 4. After loading the carbon fiber composite mooring cable 4, the buoyancy material wrapped around the first synthetic fiber cable 31 allows it to float freely on the sea surface, providing no restoring stiffness to the tested mooring system. However, the first synthetic fiber cable 31 remains connected, ready to be tensioned immediately upon needing to bear force, providing safety assurance.

[0116] Step Seven: Experimental Observation:

[0117] During the sea trial, dynamic data was monitored, including six-degree-of-freedom motion performance, maximum tension, cable morphology, and current surface condition of the cable. The dynamic data was recorded in the data acquisition system.

[0118] Static data were measured, including cable strength, as well as observation data on the corrosion surface morphology and composition of carbon fiber composite mooring cable 4 after the sea trial.

[0119] During the sea trial of the mooring system, the time when the carbon fiber composite mooring cable 4 breaks is recorded as the fatigue life. At this time, the first synthetic fiber cable 31 corresponding to the broken carbon fiber composite mooring cable 4 plays a mooring role.

[0120] The experimental scheme in step two includes the measurement of the maximum tension and morphology of the mooring cable. The measurement methods include: during the sea trial, when the carbon fiber composite mooring cable 4 is subjected to force and deformation, a single fiber optic sensor 400 monitors the tension of the carbon fiber composite mooring cable 4 in real time; when the carbon fiber composite mooring cable 4 is subjected to force and deformation, the optical path difference of multiple fiber optic sensors 400 is analyzed to obtain the strain state of different sides of the carbon fiber composite mooring cable 4, and thus the morphology of the carbon fiber composite mooring cable 4 is obtained; in step seven, the data acquisition system analyzes and processes the obtained tension data and optical path difference to obtain the maximum tension and the morphology of the cable.

[0121] A strain sensor for measuring the tension of the first synthetic fiber cable 31 is installed on the first synthetic fiber cable 31. In specific applications, in step six, when the overall shape of the second synthetic fiber cable 32 and the carbon fiber composite mooring cable 4 is the same as that of the first synthetic fiber cable 31, the two cables jointly bear the tension required for mooring. At this time, the strain sensor on the first synthetic fiber cable 31 and the fiber optic sensor 400 on the carbon fiber composite mooring cable 4 can measure the tension borne by the two cables respectively. This allows for comparison of the proportion of the two cables in the total tension, facilitating the acquisition of comparative data. This data is used to analyze the stress characteristics of the carbon fiber composite mooring cable and the synthetic fiber cable when used for mooring, and to ensure the safe and controllable loading speed during the loading process.

[0122] Therefore, the experimental design and observation methods for the experimental evaluation indicators can be summarized as follows:

[0123] The adaptability of the mooring system is mainly reflected by the motion performance of the floating structure 1, that is, by monitoring the six degrees of freedom motion performance of the floating structure 1, and measuring it through gyroscopes, accelerometers and GPS receivers, which are conventional technical means.

[0124] The strength of carbon fiber composite mooring cables is measured in the laboratory using an indoor tensile testing machine on test samples. It is the minimum breaking force, which is the force applied to the cable when it reaches this value, at which point the cable will break.

[0125] The maximum tension of the mooring cable, measured by the fiber optic sensor 400 in the carbon fiber composite mooring cable 4 during sea trials, refers to the maximum force exerted on the carbon fiber composite mooring cable 4 during the sea trial.

[0126] The morphology of the mooring cable was measured during sea trials using a combination of multiple fiber optic sensors 400 within the carbon fiber composite mooring cable 4.

[0127] The fatigue life of a mooring cable is the time it takes for the carbon fiber composite mooring cable 4 to break during sea trials, i.e., the time during which the carbon fiber composite mooring cable 4 can maintain its strength and performance during use.

[0128] The abrasion resistance of mooring cables was determined during sea trials by periodically measuring the diameter of specific parts of the carbon fiber composite mooring cable.

[0129] The corrosion resistance of the mooring cable was monitored through on-site observation during the sea trial. The carbon fiber composite mooring cable 4 was observed and inspected using equipment such as magnifying glasses and microscopes. After the sea trial, the carbon fiber composite mooring cable 4 was disassembled, and corrosion samples of the mooring cable were collected using drilling equipment and cutting tools for laboratory analysis. Equipment such as metallographic microscopes, scanning electron microscopes, and energy dispersive spectroscopy were used to observe the morphology of the corroded surface and analyze its composition.

[0130] The reliability of mooring cables is assessed through on-site observation and comprehensive analysis, including visual observation and recording, as well as comprehensive analysis of the time-domain stress, corrosion, and wear of carbon fiber composite mooring cables. Any abnormal data should be dealt with promptly and a comprehensive inspection should be conducted in a timely manner.

[0131] Step 8: Analyze the test data: Evaluate and analyze the performance of the carbon fiber composite mooring cable 4 based on dynamic and static data; the test results can be processed using statistical methods or other analytical tools.

[0132] Specifically,

[0133] First, the adaptability of the mooring system is examined. The impact of the mooring system using carbon fiber composite cable 4 on the mooring and positioning capability and six-degree-of-freedom motion performance of the floating structure 1 is evaluated and analyzed. The floating structure is required to have a small amplitude of motion in the horizontal direction, and this system should result in a small dynamic response of the floating structure. The evaluation is based on the motion amplitude and vibration of the monitoring platform. The degree of motion of the floating structure 1 is compared with that using the original mooring cable method, that is, whether the motion response performance of the floating structure is optimized and whether the environmental adaptability is improved after adopting the carbon fiber composite mooring cable.

[0134] Secondly, the maximum measured tension during sea trials of carbon fiber composite mooring cables was compared with the breaking strength. This tension value was required to be less than half of the minimum breaking tensile force. Furthermore, a comparison should be made with the original mooring cable method to determine the magnitude of the peak tension. In addition, the tension borne by the carbon fiber composite mooring cable 4 and the first synthetic fiber cable 31 when mooring and positioning the same floating structure should be analyzed to obtain the difference in tension characteristics between the carbon fiber composite mooring cable 4 and the first synthetic fiber cable 31. That is, by examining the time-domain stress characteristics of the mooring cable, its tension performance under complex marine environmental loads can be obtained, such as whether it can effectively cope with marine engineering challenges, quickly adapt and maintain tension stability under fluctuations or sudden load changes, and whether cable structure resonance will occur under external excitation.

[0135] Furthermore, the morphology of the mooring cable is analyzed using multiple fiber optic sensors 400, with a focus on conditions involving significant bending and compression. Regarding the fatigue life of the mooring cable, fatigue failure is unlikely to actually occur in the carbon fiber composite mooring cable 4 during the sea trial phase; if testing is necessary, long-term experimental observation will be conducted. The wear resistance of the mooring cable is determined by periodically measuring the diameter of specific parts of the carbon fiber composite mooring cable. The corrosion resistance of the mooring cable is determined through on-site observation or laboratory testing after recovery. The current surface condition of the cable includes wear and corrosion.

[0136] Finally, the reliability of the mooring cable was also determined through on-site observation and comprehensive assessment. During the sea trial phase, reliability accidents must be avoided. Of course, this embodiment includes safety protection measures, namely the original tested mooring system. If the carbon fiber composite material fails, the original cable will take effect.

[0137] Step Nine: Results Evaluation and Summary. Based on the test results, evaluate the performance and suitability of the carbon fiber composite mooring cable 4, summarize the lessons learned during the test, and propose improvement suggestions.

[0138] Specifically, a test report should be prepared based on the test results and conclusions. The report should include the test objectives, test methods, test results, analysis and evaluation, as well as conclusions and recommendations, and should also provide suggestions on the applicability of carbon fiber composite mooring cables to different mooring methods.

[0139] On the one hand, the sea trials verified the service performance of carbon fiber composite mooring cables in marine engineering when mooring and positioning under complex marine environments. On the other hand, the long-term service performance of carbon fiber composite mooring cables can be evaluated and analyzed through safe tests and measured data, ultimately clearing the final obstacles for the application of carbon fiber composites in marine engineering.

[0140] On the other hand, based on existing analysis, we believe that carbon fiber composite mooring cables are primarily used in mooring systems where axial tension provides restoring force, and not in sections where weight provides restoring force. In other words, carbon fiber composite mooring cables can be directly used in mooring systems with suction anchors or other anchoring foundations capable of withstanding significant uplift forces, or in combination with gravity anchors or high-holding-force anchors. Carbon fiber composite mooring cables can replace steel wire ropes, anchor chains, and high-strength polyethylene materials in synthetic fiber cables. These findings are based on theoretical derivation and summarization of existing knowledge, without actual sea trials. More accurate conclusions and recommendations need to be obtained through post-sea trial evaluation and analysis to ultimately determine the optimal use of carbon fiber composite mooring cables.

[0141] The beneficial effects of the carbon fiber composite mooring cable performance test methods in Examples 2 and 3 above are as follows:

[0142] First, the performance testing method for carbon fiber composite mooring cables is groundbreaking. Addressing the stringent requirements of offshore mooring and positioning systems, the method innovatively designs testing procedures, processes, and evaluation indicators suitable for the offshore application of carbon fiber composite mooring cables. It is technically feasible and unprecedented in the domestic and international engineering communities. The evaluation indicators, developed based on the characteristics of carbon fiber composite mooring cables, are comprehensive and scientific.

[0143] Secondly, the carbon fiber composite mooring cable performance testing equipment used is compact, reasonable, and easy to operate. The established testing method for the marine application of carbon fiber composite mooring cables can effectively evaluate the dynamic characteristics of carbon fiber composite mooring cables and further quantify their performance indicators based on this. Accurate quantitative evaluation can ensure that carbon fiber composite mooring cables can effectively moor and position the main floating structure when facing severe sea conditions such as typhoons, thus improving the effectiveness of the mooring system.

[0144] Third, by embedding multiple fiber optic sensors 400 in the fiber bundles of the carbon fiber composite mooring cable 4, the stress information of the carbon fiber composite mooring cable during the test process can be more accurately and comprehensively evaluated from both tensile and morphological aspects, and the axial tensile force and end-point movement information of the carbon fiber composite mooring cable can be monitored in real time under complex marine environments.

[0145] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A performance testing device for carbon fiber composite mooring cables, characterized in that: Includes a floating structure (1) and one or more mooring cable groups for mooring the floating structure (1), each mooring cable group corresponding to a mooring point; A set of mooring cables includes a first winch (21) and a second winch (22) disposed on the upper part of the floating structure (1). The side of the floating structure (1) is provided with a first cable guide hole (210) and a second cable guide hole (220). The first cable guide hole (210) matches the first winch (21), and the second cable guide hole (220) matches the second winch (22). The first winch (21) is connected to a first synthetic fiber cable (31), and the second winch (22) is connected to a second synthetic fiber cable (32). It also includes an anchoring foundation (8) submerged on the seabed, a water drum (6) floating on the water surface, and an anchor chain assembly (7). The lower end of the anchor chain assembly (7) is connected to the anchoring foundation (8), the upper end of the anchor chain assembly (7) is provided with the water drum (6), and the upper end of the anchor chain assembly (7) is equipped with a three-eyed plate (5). The lower end of the first synthetic fiber cable (31) passes through the first cable guide hole (210) and is connected to the three-eye plate (5). The lower end of the second synthetic fiber cable (32) passes through the second cable guide hole (220) and is connected to the upper end of the carbon fiber composite mooring cable (4) to be tested. The lower end of the carbon fiber composite mooring cable (4) is connected to the three-eye plate (5). The cross-section of the carbon fiber composite mooring cable (4) is circular. The carbon fiber composite mooring cable (4) includes multiple conventional carbon fiber rods (401) and multiple measuring carbon fiber rods (402). The conventional carbon fiber rods (401) and the measuring carbon fiber rods (402) are assembled to form a carbon fiber bundle. One measuring carbon fiber rod (402) is located at the center of the carbon fiber bundle, and the remaining measuring carbon fiber rods (402) are evenly distributed in a ring array with the center of the carbon fiber bundle as the center. The structure of a single measuring carbon fiber rod (402) includes an optical fiber sensor (400), the length of which is adapted to the length of the carbon fiber composite mooring cable (4), and the optical fiber sensor (400) is wrapped with carbon fiber filaments.

2. The carbon fiber composite mooring cable performance testing device as described in claim 1, characterized in that: The lower end of the first synthetic fiber cable (31) is provided with a first shackle by means of insertion and braiding, and the first shackle is connected to the three-eye plate (5); The lower end of the second synthetic fiber cable (32) is provided with a second shackle by means of insertion and braiding, and the second shackle is connected to the upper end of the carbon fiber composite mooring cable (4).

3. The carbon fiber composite mooring cable performance testing device as described in claim 1, characterized in that: The surface of the first synthetic fiber cable (31) is provided with buoyancy material.

4. The carbon fiber composite mooring cable performance testing device as described in claim 1, characterized in that: The upper end of the carbon fiber composite mooring cable (4) is provided with a third shackle, and the lower end of the carbon fiber composite mooring cable (4) is provided with a fourth shackle. The third shackle is connected to the first synthetic fiber cable (31), and the fourth shackle is connected to the second synthetic fiber cable (32).

5. A test method for the performance of carbon fiber composite mooring cables, characterized in that: Step 1: Establish test evaluation indicators for the marine application of carbon fiber composite mooring cables (4). The test evaluation indicators include mooring system adaptability, mooring cable strength, mooring cable maximum tension, mooring cable morphology, mooring cable fatigue life, mooring cable wear resistance, mooring cable corrosion resistance and mooring cable reliability. Step 2: Design the test plan based on the test evaluation indicators; Step 3: Prepare the equipment and instruments for the test, including a carbon fiber composite mooring cable performance testing device as described in claim 1, and a data acquisition system; Step 4: Analyze and determine the position and length of the carbon fiber composite mooring cable (4) to be tested relative to the floating structure (1); Step 5: Multiple fiber optic sensors (400) are embedded in the fiber bundle of the carbon fiber composite mooring cable (4). The fiber optic sensors (400) are arranged along the length of the carbon fiber composite mooring cable (4). The length of the fiber optic sensors (400) is adapted to the length of the carbon fiber composite mooring cable (4). A carbon fiber composite mooring cable performance testing device is set up to form a test mooring system. The carbon fiber composite mooring cable (4) to be tested is installed. The fiber optic sensors (400) are connected to the data acquisition system. At this time, the carbon fiber composite mooring cable (4) is suspended and without pretension, and the first synthetic fiber cable (31) is in a tensioned state. Step Six: Apply load to the carbon fiber composite mooring cable (4) until the carbon fiber composite mooring cable (4) fully bears the mooring force of the mooring cable in the corresponding direction. After the carbon fiber composite mooring cable (4) is loaded, the experimental mooring system can be put into sea trial; Step Seven: Experimental Observation: During the sea trial, dynamic data was monitored, including six-degree-of-freedom motion performance, maximum tension, cable morphology, and current surface condition of the cable. The dynamic data was recorded in the data acquisition system. Static data were measured, including cable strength, as well as observation data on the corrosion surface morphology and composition of the carbon fiber composite mooring cable (4) after the sea trial. Step 8: Analyze the test data: Based on the dynamic and static data, evaluate and analyze the performance of the carbon fiber composite mooring cable (4); Step Nine: Results Evaluation and Summary.

6. The test method for the performance of carbon fiber composite mooring cables as described in claim 5, characterized in that: In step six, the loading method for the carbon fiber composite mooring cable (4) includes: Start the second winch (22) to gradually tighten the second synthetic fiber cable (32) so that the carbon fiber composite mooring cable (4) gradually bears the tension. When the overall shape of the second synthetic fiber cable (32) and the carbon fiber composite mooring cable (4) is the same as the configuration of the first synthetic fiber cable (31), start the first winch (21) to release the first synthetic fiber cable (31) so that the first synthetic fiber cable (31) is in a relaxed state. The first synthetic fiber cable (31) floats on the sea surface under the action of the buoyancy material outside it, so that the carbon fiber composite mooring cable (4) bears the mooring tension completely independently.

7. The test method for the performance of carbon fiber composite mooring cables as described in claim 5, characterized in that: The test plan in step two includes measurements of the maximum tension and morphology of the mooring cable, and the measurement methods include: During the sea trial, the single fiber optic sensor (400) monitored the tension on the carbon fiber composite mooring cable (4) in real time when it was subjected to stress and deformation. When the carbon fiber composite mooring cable (4) is subjected to stress and deformation, the optical path difference of multiple optical fiber sensors (400) is analyzed to obtain the strain state of different sides of the carbon fiber composite mooring cable (4), and then the morphology of the carbon fiber composite mooring cable (4) is obtained. In step seven, the data acquisition system analyzes and processes the obtained tension data and optical path difference data to obtain the maximum tension and cable shape.

8. The test method for the performance of carbon fiber composite mooring cables as described in claim 5, characterized in that: During the sea trials of the mooring system, the time of fracture of the carbon fiber composite mooring cable (4) was recorded as the fatigue life. At this time, the first synthetic fiber cable (31) corresponding to the broken carbon fiber composite mooring cable (4) plays a mooring role.

9. The test method for the performance of carbon fiber composite mooring cables as described in claim 6, characterized in that: A strain sensor for measuring the tension of the first synthetic fiber cable (31) is provided on the first synthetic fiber cable (31).

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