Spindle-shaped tension cable net floating structure and mounting method thereof

Abstract

The invention discloses a spindle-shaped tension cable net floating structure and a mounting method thereof, and belongs to the technical field of ocean engineering.The structure mainly adopts at least one buoyancy ring, a central stand column is vertically arranged in the at least one buoyancy ring, and the two ends of the central stand column are connected through a plurality of prestress connecting bodies; the floating platform is connected with at least one buoyancy ring in the annular direction, so that the whole floating platform is in a spindle shape, most buoyancy of the floating platform is provided through the buoyancy rings, the distribution of the waterline area is far away from the center position, and correspondingly, the stability radius of the buoyancy rings and the stability height of the whole structure are greatly improved; in addition, the CFRP inhaul cable has the advantages of being light in weight, high in strength, resistant to corrosion, low in relaxation and the like, and the integrity of the structure can be well kept.

Description

Technical Field

[0001] The present invention belongs to the field of marine engineering technology, and more specifically, relates to a spindle-shaped tension cable net floating structure and an installation method thereof. Background Art

[0002] Since the 20th century, with rapid socioeconomic development, the global demand for energy has skyrocketed. To address the depletion of non-renewable energy resources and the deteriorating environment, the search for alternative, renewable, and clean energy sources has become a global consensus. The ocean, which covers 70% of the Earth's surface, not only possesses abundant resources such as aquatic products and oil, but also holds vast energy reserves. Marine energy primarily exists in the form of tides, waves, temperature differences, salinity gradients, and ocean currents. The utilization of ocean energy holds significant potential, and increasing its development and research is of great significance.

[0003] In deep-sea environments, the safety and overall economic viability of fixed foundation piles present significant challenges, leading to the emergence of floating structures. However, the wind, wave, and current loads in deep-sea environments are far more complex and severe than those in inland waters. Designing deep-sea floating structures presents significant challenges in addressing these harsh operating environments, improving the hydrodynamic performance of structures, and ensuring economical operation.

[0004] Currently, the commonly used semi-submersible wind turbine foundations mostly adopt a "3-column" or "3-column + middle column" layout. This type of floating foundation cannot distribute the load efficiently and is easily affected by extreme wave conditions.

[0005] Given this, optimization is necessary. Related optimization solutions have been proposed within the field, such as patents CN2395542Y and CN109398633A, which primarily place buoyancy on the central column. However, this approach of relying on the central column for primary buoyancy still suffers from a small stability radius, low stability height, poor hydrodynamic performance, and poor structural self-stability. Therefore, further optimization is still needed. Summary of the Invention

[0006] In response to the shortcomings of the existing technology, the present invention provides a spindle-shaped tension cable net floating structure and its installation method, which provides most of the buoyancy of the floating platform through the buoyancy ring, so that the distribution of the waterline area is far away from the center position. In this way, the stability radius of the buoyancy ring and the stability height of the overall structure are greatly improved. Under the condition of large-diameter buoyancy ring, the structure has better self-stability, thereby solving the technical problems described in the background technology.

[0007] To achieve the above objectives, the present invention is realized through the following technical solutions: A spindle-shaped tension cable net floating structure includes at least one buoyancy ring. A central column is vertically arranged in the at least one buoyancy ring. The at least one buoyancy ring is connected with multiple prestressed connectors. The multiple prestressed connectors are respectively inclined in the upper and lower directions and are connected to the central column in an annular distribution manner, so that the whole forms a spindle shape.

[0008] Optionally, it includes two buoyancy rings, namely the first buoyancy ring and the second buoyancy ring. The first buoyancy ring and the second buoyancy ring are stacked at intervals and fixedly connected through a connecting column. The multiple prestressed connectors on the first buoyancy ring and the second buoyancy ring are respectively inclined in the upper or / and lower directions and are connected to the central column in an annular distribution manner.

[0009] Optionally, the buoyancy of the first buoyancy ring in water is greater than the buoyancy of the second buoyancy ring in water.

[0010] Optionally, a mooring cable is connected to the first buoyancy ring or / and the second buoyancy ring. By pulling the mooring cable, the first buoyancy ring is on the water surface and the second buoyancy ring is completely immersed underwater.

[0011] Optionally, the prestressed connector is a prestressed rigid rod or a prestressed cable.

[0012] Optionally, the prestressed cable is a CFRP cable.

[0013] Optionally, the buoyancy ring includes an outer protective shell, an intermediate buoyancy block, and an inner annular skeleton. The protective shell is a plastic hard shell of polyurethane or HDPE. The buoyancy block is one or a combination of hollow microsphere composites, composite plastics, and chemical foam composites.

[0014] Optionally, the annular skeleton is formed by splicing or welding multiple skeleton units through flange plates. The annular skeleton is one of a tubular shape, a truss, and a box shape.

[0015] Optionally, the annular skeleton includes two annular bodies. The two annular bodies are stacked at intervals and connected together through connecting vertical rods and / or connecting diagonal rods.

[0016] To achieve the objective, according to the spindle-shaped tension cable net floating structure, the present invention also provides an installation method for the spindle-shaped tension cable net floating structure. The key lies in the following steps:

[0017] S1: Set a hoop device on the central column that can move along its axial direction;

[0018] S2: Manufacture multiple prestressed connectors with the same length, and divide the multiple prestressed connectors into two upper and lower groups with the same quantity.

[0019] S3: Hinge one end of the prestressed connectors in the corresponding upper and lower groups to the buoyancy ring, and hinge the other end to the ferrule device or the end of the central column far from the ferrule device.

[0020] S4: The ferrule device moves axially along the central column. When the prestressed connectors reach the designed tension value, stop moving and lock the ferrule device through the fixing device.

[0021] The present invention provides a spindle-shaped tension cable net floating structure and its installation method, having the following beneficial effects:

[0022] 1. Provide most of the buoyancy of the floating platform through the buoyancy ring, make the distribution of the waterline area far from the central position, and the section moment of inertia increases with the fourth power of the diameter. Accordingly, the stability radius of the buoyancy ring and the stability height of the overall structure are greatly improved, and under the condition of a large-diameter buoyancy ring, it has good structural self-stability.

[0023] 2. The prestressed cable is made of CFRP, which has the properties of light weight, high strength, corrosion resistance, and fatigue resistance. Its performance is far higher than that of traditional steel cables and synthetic fiber ropes. In addition, the long-term relaxation performance of CFRP cables is much lower than that of synthetic fiber ropes. In a floating structure, there will be no problem of large tensile force attenuation leading to structural failure.

[0024] 3. The buoyancy rings arranged in a stacked manner at intervals are connected by connecting columns to further form a space truss, greatly improving the strength, stiffness, and integrity of the structure, and helping to maintain the integrity of the structure during the transportation and installation stages.

[0025] 4. Multiple densely arranged prestressed connectors are connected to the buoyancy ring and the central column, making the structure have a large redundant constraint, and at the same time, it is a high-order hyperstatic structure, making the structural system have good robustness and safety.

[0026] 5. The buoyancy provided by the upper buoyancy ring is greater than that of the lower buoyancy ring, which helps to improve the position of the floating center of the structure. The self-weight of the lower buoyancy ring is relatively large, which can reduce the height of the center of gravity of the structure. This design of upper light and lower heavy will further improve the self-floating stability of the structure.

[0027] 6. The structure of the present invention has a light self-weight. Compared with the traditional semi-submersible foundation, the cost is greatly reduced, which is beneficial to the popularization and use of the structure. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of the spindle-shaped tension cable net floating structure provided in the first embodiment;

[0029] Figure 2 Simplified schematic diagram of the first-axisymmetric structure connection form provided in the first embodiment;

[0030] Figure 3 Simplified schematic diagram of the second-axisymmetric structure connection form provided in the first embodiment;

[0031] Figure 4 Simplified schematic diagram of the third-axisymmetric structure connection form provided in the first embodiment;

[0032] Figure 5 Schematic diagram of the structure used in the spindle-shaped tension cable net floating structure provided in the first embodiment;

[0033] Figure 6 Cross-sectional schematic diagram of the buoyancy ring structure provided in the first embodiment;

[0034] Figure 7 Schematic diagram of the double-layer annular framework buoyancy ring provided in the first embodiment;

[0035] Figure 8 Comparison curve graph of the stability radii of the buoyancy ring structure and the central column structure provided in the first embodiment;

[0036] Figure 9 Schematic diagram of the installation method of the spindle-shaped tension cable net floating structure provided in the second embodiment.

[0037] In the figure: 1. Buoyancy ring; 101. Protective shell; 102. Buoyancy block; 103. Annular framework; 104. Annular main body; 105. Connecting vertical rod; 106. Connecting diagonal rod; 11. First buoyancy ring; 12. Second buoyancy ring; 2. Central column; 3. Prestressed connection body; 31. Prestressed cable; 32. Prestressed rigid rod; 4. Connecting column; 5. Mooring cable; 6. Ferrule device; 7. Fixed base. Specific implementation manners

[0038] The following further describes in detail the implementation manners of the present invention in conjunction with the accompanying drawings and embodiments. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0039] Embodiment 1:

[0040] A spindle-shaped tension cable net floating structure, as Figure 1As shown in the figure, the structure mainly includes at least one buoyancy ring 1. A central column 2 is vertically arranged in at least one buoyancy ring 1. Preferably, the central column 2 is located at the center of the buoyancy ring 1. At least one buoyancy ring 1 is connected with a plurality of prestressed connectors 3. The plurality of prestressed connectors 3 are respectively inclined in the upper and lower directions and are connected with the central column 2 in an annular distribution manner, so that the whole forms a spindle shape. This buoyancy ring 1 structure provides most of the buoyancy of the floating platform. The distribution of the waterline area is far from the central position. The sectional moment of inertia increases with the fourth power of the diameter size. Correspondingly, the stability radius of the buoyancy ring 1 and the stability height of the overall structure are greatly improved. Under the condition of a large-diameter buoyancy ring 1, the self-stability of the structure is extremely good. At the same time, a plurality of densely arranged prestressed connectors 3 are connected. This redundant design can ensure the robustness or strength of the overall structure.

[0041] Preferably, the buoyancy ring 1 is designed to be more than two. Taking two as an example, the two buoyancy rings 1 are respectively the upper first buoyancy ring 11 and the lower second buoyancy ring 12. The first buoyancy ring 11 and the second buoyancy ring 12 are stacked at intervals and fixedly connected through a connecting column 4. The plurality of prestressed connectors 3 on the first buoyancy ring 11 and the second buoyancy ring 12 are respectively inclined in the upper or / and lower directions and are connected with the central column 2 in an annular distribution manner. Generally speaking, the upper and lower chord bodies of the spindle shape can be correspondingly arranged on the upper and lower annular structures, or can be staggered on the upper and lower annular structures. The specific connection method is that one end is hinged on the buoyancy ring 1 and the other end is hinged with the central column 2 to form an integral structure. Among them, there are also various permutations and combinations of the connection forms, such as Figures 2 - 4 As shown in the figure, the specific connection form selected needs to be determined according to the actual application scenario and the force condition.

[0042] In order to make the structure have overall stiffness, the prestressed connectors 3 arranged regularly in the circumferential direction should have sufficient tensile stress reserve when tensioned to ensure that they are always in a stable state under the working condition. The best inclination angle of the prestressed connector 3 with the horizontal plane is 55°. The prestressed connectors 3 should be evenly distributed on the structure. Among them, the prestressed connector 3 is a prestressed rigid rod 32 or a prestressed cable 31. As Figures 2 - 4 As shown in the figure, preferably, the setting methods of the upper and lower chord bodies are different, which is beneficial to the "permanence" of the structure. When the prestressed connector 3 is a prestressed cable 31, the prestressed cable 31 should have the properties of corrosion resistance, small relaxation and low creep. Therefore, the prestressed cable 31 is a CFRP cable (Carbon Fiber Reinforced Polymer carbon fiber reinforced composite material).

[0043] In addition, the central column 2 is a steel truss structure without buoyancy setting. The top can be used for installing various types of equipment, such as wind turbines or photovoltaic systems, etc. The bottom of the central column 2 can be used for installing a mooring system and counterweights, and the buoyancy ratio of the two buoyancy rings 1 can be adjusted.

[0044] Control scheme for the buoyancy ratio of two buoyancy rings 1, such as Figure 1 shown, the two buoyancy rings 1 are designed such that the buoyancy of the first buoyancy ring 11 in water is greater than the buoyancy of the second buoyancy ring 12 in water. That is, the gravity of the second buoyancy ring 12 will be greater than that of the first buoyancy ring 11, making the center of buoyancy of the overall structure higher than the center of gravity. Such an arrangement will lower the center of gravity of the entire structure and can further improve the stability of the structure.

[0045] During use, as Figure 5 shown, a mooring cable 5 is connected to the first buoyancy ring 11 or / and the second buoyancy ring 12. Preferably, the lowermost buoyancy ring 1 is connected, and the other end of the mooring cable 5 is connected to a fixed base 7. The fixed base 7 can be an embedded anchor or a gravity anchor, etc. By the pulling of the mooring cable 5, the first buoyancy ring 11 is on the water surface, and the second buoyancy ring 12 is completely submerged underwater.

[0046] Regarding the buoyancy ring 1:

[0047] As Figure 6 shown, the buoyancy ring 1 includes an outer protective shell 101, an intermediate buoyancy block 102, and an inner ring-shaped skeleton 103. The ring-shaped skeleton 103 serves as an internal support, and the buoyancy block 102 provides the main buoyancy for the buoyancy ring 1. Among them, the protective shell 101 is a plastic hard shell of polyurethane or HDPE, and the buoyancy block 102 is one or a combination of hollow microsphere composites, composite plastics, and chemical foam composites. The buoyancy block 102 can be prefabricated in a factory or can be externally wrapped after being towed to the site, etc.

[0048] The ring-shaped skeleton 103 is formed by splicing or welding multiple sections of skeleton units through flange plates, that is, conventional steel is processed in sections and assembled into a whole in the form of flange plates, or welded into a whole. Among them, the form of the ring-shaped skeleton 103 is diverse, and its cross-sectional form can be tubular, truss, box-shaped, etc., and is not limited to Figure 6 the form in

[0049] As Figure 7 shown, the ring-shaped skeleton 103 can adopt a double-layer or multi-layer ring-shaped main body 104. Taking two ring-shaped main bodies 104 as an example, the two ring-shaped main bodies 104 are stacked at intervals and connected together by connecting vertical rods 105 and / or connecting diagonal rods 106, so that the structural strength and stiffness of the buoyancy ring 1 in the overall form are greatly improved compared with the buoyancy ring 1 in the form of a single ring-shaped skeleton 103.

[0050] In order to demonstrate the stability superiority of the above buoyancy ring structure, the following demonstration is made:

[0051] 1. The main buoyancy provided on the upper platform of the central column is provided by the central column.

[0052] For the convenience of calculation, assume that the waterplane of the central column buoy is a circular cross-section, and let the diameter be d1. Then the circular cross-sectional area and moment of inertia are respectively:

[0053]

[0054]

[0055] Then the radius of stability:

[0056]

[0057] where V1 is the displacement volume of the floating platform.

[0058] 2. Buoyancy setting The main buoyancy of the upper platform of the annular structure is provided by the annular structure

[0059] For the convenience of calculation, assume that the waterplane of the annular structure is in the shape of a ring. Assume that the outer diameter of the annular structure is D and the inner diameter is d2. Then the ring cross-sectional area and moment of inertia are respectively:

[0060]

[0061]

[0062] Then the radius of stability:

[0063]

[0064] where V2 is the displacement volume of the floating platform.

[0065] Assume that in the case of the same waterplane area for the two structures, there is:

[0066] S1 = S2; we get: Simplified to: D 2 = d1 2 + d2 2

[0067] Assume that the displacement volumes of the two structures are equal, V1 = V2. Then the ratio of the radii of stability of the two structures:

[0068]

[0069] Finally simplified to:

[0070]

[0071] Such as Figure 8As shown, when d2 / d1 increases, the ratio of R2 / R1 increases significantly by a factor of square, indicating that as the diameter of the annular structure becomes larger, the stability radius of the structure will increase rapidly, far higher than the stability of setting buoyancy on the central column. And the size of the stability radius is closely related to the stability height of the floating platform. Therefore, the stability of the buoyancy annular structure is much better than that of the buoyancy central column structure.

[0072] Embodiment 2:

[0073] As Figure 9 shown, based on the structure of Embodiment 1, this embodiment provides an installation method for a spindle-shaped tension cable net floating structure, which mainly includes the following steps:

[0074] S1: Set a hoop device 6 on the central column 2 that can move along its axial direction;

[0075] S2: Manufacture multiple prestressed connectors 3 with the same length, and divide the multiple prestressed connectors 3 into two equal groups, upper and lower;

[0076] S3: Hinge one end of the prestressed connectors 3 in the corresponding upper and lower groups to the buoyancy ring 1, and the other end to the hoop device 6 or the end of the central column 2 away from the hoop device 6;

[0077] S4: The hoop device 6 moves along the axial direction of the central column 2 where it is located, and the moving distance is determined according to the actual required cable force. When the prestressed connector 3 reaches the tension design value, stop moving and lock the hoop device 6 through a fixing device.

[0078] It should be noted that one or two hoop devices 6 can be set. If one is set, among the upper and lower groups of prestressed connectors 3, one group is connected to the hoop device 6, and the other group is connected to the end of the central column 2 where the hoop device 6 is not installed. If two hoop devices 6 are set, the two groups of prestressed connectors 3 are respectively connected to the two hoop devices 6. If there are two hoop devices 6, the two hoop devices 6 can be moved simultaneously during tensioning, or one can be fixed first and then the other hoop device 6 can be moved.

[0079] This way of setting the hoop device 6 can make the spindle-shaped tension cable net floating structure have good prestress. After installation, the structure buoyancy is set on the annular structure, and most of the buoyancy is provided by the buoyancy ring 1. This setting method is better than setting the buoyancy on the central column 2, and the stability radius is much higher than the way of setting the buoyancy on the central column 2.

[0080] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, shall be covered by the protection scope of the present invention.

Claims

1. A spindle-shaped tension cable net floating structure, characterized in that: It includes at least one buoyancy ring (1), in which a central column (2) is vertically arranged. The at least one buoyancy ring (1) is connected with a plurality of prestressed connectors (3). The plurality of prestressed connectors (3) are inclined in two directions of up and down respectively and are connected with the central column (2) in an annular distribution manner, so that the whole forms a spindle shape.

2. The spindle-shaped tension cable net floating structure according to claim 1, wherein: It includes two buoyancy rings (1), namely a first buoyancy ring (11) and a second buoyancy ring (12). The first buoyancy ring (11) and the second buoyancy ring (12) are stacked at intervals and fixedly connected through a connecting column (4). The plurality of prestressed connectors (3) on the first buoyancy ring (11) and the second buoyancy ring (12) are inclined in two directions of up or / and down respectively and are connected with the central column (2) in an annular distribution manner.

3. The spindle-shaped tension cable net floating structure according to claim 2, wherein: The buoyancy of the first buoyancy ring (11) in water is greater than that of the second buoyancy ring (12) in water.

4. The spindle-shaped tension cable net floating structure according to claim 2 or 3, characterized in that: A mooring cable (5) is connected to the first buoyancy ring (11) or / and the second buoyancy ring (12). By pulling the mooring cable (5), the first buoyancy ring (11) is on the water surface, and the second buoyancy ring (12) is completely immersed underwater.

5. The spindle-shaped tension cable net floating structure according to any one of claims 1-3, characterized in that: The prestressed connector (3) is a prestressed rigid rod (32) or a prestressed cable (31).

6. The spindle-shaped tension cable net floating structure according to claim 5, wherein: The prestressed cable (31) is a CFRP cable.

7. The spindle-shaped tension cable net floating structure according to any one of claims 1-3, characterized in that: The buoyancy ring (1) includes an outer protective shell (101), an intermediate buoyancy block (102) and an inner annular skeleton (103). The protective shell (101) is a plastic hard shell of polyurethane or HDPE. The buoyancy block (102) is one or a combination of hollow microsphere composite materials, composite plastics, chemical foam composite materials, etc.

8. The spindle-shaped tension cable net floating structure according to claim 7, characterized in that: The annular skeleton (103) is formed by splicing or welding multiple skeleton units through flange plates. The annular skeleton (103) is one of tubular, truss, box type, etc.

9. The spindle-shaped tension cable net floating structure according to claim 7, wherein: The annular skeleton (103) includes two annular bodies (104). The two annular bodies (104) are stacked at intervals and are connected together through connecting vertical rods (105) and / or connecting diagonal rods (106).

10. A method for installing a spindle-shaped tension cable net floating structure, which is used to install the spindle-shaped tension cable net floating structure according to any one of claims 1-9, characterized in that, It includes the following steps: S1: A hoop device (6) that can move axially along the central column (2) is arranged on the central column (2); S2: A plurality of prestressed connectors (3) are made according to the same length, and the plurality of prestressed connectors (3) are divided into two groups of the same number, upper and lower; S3: One end of the prestressed connectors (3) in the corresponding upper and lower groups is hinged to the buoyancy ring (1), and the other end is hinged to the hoop device (6) or the end of the central column (2) far from the hoop device (6); S4: The hoop device (6) moves axially along the central column (2). When the prestressed connector (3) reaches the tension design value, stop moving and lock the hoop device (6) through a fixing device.

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