Multi-layer pore plate structure for shock absorption of ultra-large floating body

Abstract

The invention relates to the field of ocean engineering, and discloses a multi-layer pore plate structure for shock absorption of an ultra-large floating body, the structure is composed of a plurality of pore plates which are horizontally arranged, and the pore plates are rigidly connected with the floating body through fixing devices and are made of high-strength light materials; open pores are uniformly distributed in the surface of each pore plate, and the porosity, the plate spacing, the water entry depth and the plate layer number of the pore plates can be flexibly adjusted according to the working environment and the wave condition of the floating body; the porosity range is 6%-15%, the distance between the plates is 4.2%-16.7% of the working water depth of the floating body, and the water entering depth is 1-3 times of the height of the wave below the bottom surface of the floating body; through reasonable design and arrangement, the multiple layers of porous plates can effectively reduce transmission and reflection of wave energy, the energy dissipation capacity is enhanced, and vibration reduction of the head wave side and dynamic stability of the back wave side are achieved; the damping device has the characteristics of flexible structural design, remarkable damping effect and wide application range, and is suitable for offshore and deep sea ultra-large floating body engineering.

Description

Technical Field

[0001] The invention relates to the technical field of marine engineering, in particular to a multi-layer porous plate structure used for shock absorption of a super-large floating body. Background Art

[0002] As a new type of marine structure, very large floating structures (VLFS) have attracted extensive attention in the field of marine development in recent years due to their broad application prospects and engineering advantages. However, in actual operation, the hydroelastic response of VLFS under wave action and the maximum force of the mooring system are key technical problems. The existence of these problems not only affects the stability and durability of the floating structure, but also poses a severe challenge to the safety of the mooring system.

[0003] Existing vibration reduction methods mainly rely on adjusting the stiffness or mass of the floating body itself, and adding external vibration reduction devices to mitigate the impact of wave energy on the floating body. Among them, although the stiffness and mass adjustment method can improve the dynamic response of the floating body to a certain extent, it usually increases the design complexity and construction cost of the floating body, and it is difficult to adapt to complex wave conditions. External vibration reduction devices, such as breakwaters or floating energy dissipation structures, although effective, often require a large layout space and have limited effect in high wave energy environments.

[0004] Regarding the application of porous plate structures, existing studies have shown that single-layer or double-layer porous plates have certain vibration reduction capabilities, especially they can reduce the hydroelastic response of the wave-facing side of the floating body by dissipating wave energy. However, the existing porous plate design has limitations in structural performance. For example, the single-layer design is difficult to meet the vibration reduction requirements under multi-wavelength conditions, and the energy dissipation efficiency of the double-layer design is still not ideal in high wave energy environments. In addition, the optimization range of key parameters such as porosity, plate spacing and immersion depth is still unclear, resulting in a lack of sufficient guidance and adaptability in actual engineering. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a multi-layer porous plate structure for shock absorption of super-large floating bodies, which solves the problems of insufficient vibration absorption performance, low energy dissipation efficiency and difficulty in adapting to complex wave conditions of single-layer or double-layer porous plate structures in the prior art.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a multi-layer porous plate structure for shock absorption of a super-large floating body, comprising a plurality of horizontally arranged porous plates, the plurality of porous plates are interconnected to form a multi-layer porous plate structure, each porous plate is made of a high-strength lightweight material, and the surface of the porous plate is provided with evenly distributed openings, the multi-layer porous plate is connected to the super-large floating body structure through a fixing device, and is used to reduce the hydroelastic response and maximum mooring force of the floating body, wherein:

[0007] The porosity of the porous plate is 6% to 15%.

[0008] The number of porous plate layers is 2 to 4.

[0009] The spacing between adjacent porous plates is 4.2% to 16.7% of the working water depth of the floating body.

[0010] The immersion depth of the porous plate is 1 to 3 times the wave height below the bottom of the floating body.

[0011] Preferably, the porous plate is a lightweight and high-strength material, including an acrylic plate or a polycarbonate plate.

[0012] Preferably, the horizontal position of the aperture plate is adjustable, specifically:

[0013] The distance between the front position of the porous plate on the wave-facing side and the front position of the floating body model is 0.25 to 1 times the length of the porous plate;

[0014] The rear edge position of the aperture plate on the back-wave side can be adjusted toward the wave-facing direction or the back-wave direction of the floating body according to the wavelength, and the adjustment range is 0.25 times to 1 times the length of the aperture plate.

[0015] Preferably, the porous plate is connected to the floating body by a rigid connection or an elastic connection, using bolt fixation, adjustable slide rail installation or elastic support to adapt to different wave frequencies and mooring methods.

[0016] Preferably, the multi-layer porous plate structure is installed on the wave-facing side or on both the wave-facing side and the wave-receiving side of the floating body. When installed on both sides, the porosity and number of layers of the porous plate on the wave-facing side and the wave-receiving side can be adjusted respectively to optimize the vibration reduction effect on the wave-facing side and the wave-receiving side.

[0017] Preferably, an elastic buoy is provided between adjacent porous plates on the wave-facing side or the wave-back side. The elastic buoy is fixed between adjacent porous plates through a fishing net or a frame structure. The elastic buoy is made of rubber with a density close to that of water.

[0018] Preferably, the multi-layer porous plate structure is suitable for a floating system using a seabed anchor chain mooring method or a mooring bollard mooring method, specifically:

[0019] In the submarine anchor chain mooring mode, the double-side installation mode is adopted;

[0020] In the bollard mooring mode, the single-side installation mode on the wave-facing side is adopted.

[0021] Preferably, the multi-layer porous plate structure adjusts the wave reflection coefficient, transmission coefficient and energy dissipation coefficient of the floating body by changing the porosity, plate spacing, number of layers, horizontal position and water immersion depth of the porous plate to adapt to different marine environments and wave conditions.

[0022] Preferably, the multilayer porous plate structure can reduce the maximum value of the hydroelastic response of the wave-facing side and the wave-receiving side of the float under wave conditions where the ratio of the wavelength to the float length is less than 0.3; under wave conditions where the ratio of the wavelength to the float length is greater than 0.3, the vibration reduction effect is concentrated on the wave-facing side of the float.

[0023] The present invention provides a multi-layer porous plate structure for shock absorption of super-large floating bodies. It has the following beneficial effects:

[0024] 1. The present invention significantly reduces the hydroelastic response of the very large floating body (VLFS) under wave action by adopting a multi-layer porous plate structure, especially on the wave-facing side. Under medium and short wave conditions, the optimized porosity, plate spacing and immersion depth can effectively reduce the vibration amplitude of the floating structure and improve the structural stability, thereby meeting the strict requirements of marine engineering to resist wave disturbances.

[0025] 2. By adjusting the geometric parameters and installation methods of the aperture plate (including single-side or double-side installation, multi-layer design, etc.), the present invention can reduce the maximum mooring force of the VLFS, especially showing a good reduction effect in the short-wave range. This performance optimization helps to extend the service life of the mooring system, reduce its peak force, and improve the safety and reliability of the system.

[0026] 3. The porous plate structure significantly enhances the dissipation effect of wave energy through porous design and layer optimization. When waves pass through the porous plate, the fluid flows in the pores to generate friction resistance and eddy current dissipation. The two work together to effectively reduce the transmission energy of the wave and improve the overall vibration reduction effect, thereby achieving control of the flow field around the VLFS.

[0027] 4. The present invention can exhibit excellent performance in different wavelength ranges (short wave, medium wave and long wave) by reasonably designing the parameters of the porous plate (such as porosity, plate spacing, water immersion depth, etc.), especially achieving the best vibration reduction effect in the medium wave range, and has good environmental adaptability and wide engineering applicability.

[0028] 5. The multi-layer porous plate structure allows the adjustment of the number of layers, plate spacing and porosity to meet different engineering requirements. This modular design facilitates flexible configuration in engineering implementation, adapting to different floating structures, wave conditions and vibration reduction targets, while reducing the difficulty of manufacturing and installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a structural diagram of a multi-layer porous plate of the present invention;

[0030] Figure 2 It is a schematic diagram of the aperture plate of the present invention;

[0031] Figure 3It is a schematic diagram of a U-shaped connector of the present invention;

[0032] Figure 4 It is a schematic diagram of the installation position of the fixing device of the present invention;

[0033] Figure 5 A schematic diagram of filling elastic floating balls into the multi-layer porous plate of the present invention;

[0034] Figure 6 This is a schematic diagram of the composition of the VLFS model material of the present invention;

[0035] Figure 7 It is a schematic diagram of the arrangement of the VLFS model in water of the present invention;

[0036] Figure 8 It is a schematic diagram of the mooring method of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings of the present invention specification to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Please refer to the attached Figure 1 -Attached Figure 8 The present invention provides a multi-layer porous plate structure for shock absorption of a very large floating body, aiming to solve the problems of insufficient vibration reduction effect, poor adaptability and limited mooring force optimization of single-layer or double-layer porous plates on very large floating structures (VLFS) in the prior art. By optimizing the structural parameters and arrangement of the multi-layer porous plates, the hydroelastic response and maximum mooring force of the floating body under the action of regular waves and irregular waves can be significantly reduced, thereby improving the stability and safety of the very large floating structure.

[0039] The multilayer porous plate of the present invention is proposed based on laboratory three-dimensional physical model tests and related theoretical research, and has efficient vibration reduction performance and wide applicability.

[0040] In the physical model test of VLFS, the geometric similarity ratio, mass similarity and stiffness similarity of the model were strictly controlled. The test adopted a 1:50 scale ratio to test the vibration reduction effect of the porous plate structure under different wave conditions. The test covered a wavelength range from 0.6 meters to 7.2 meters, and the prototype wavelength was 30 meters to 360 meters, covering most of the wavelength range of the actual VLFS working environment. Based on the test results, the various parameters of the multi-layer porous plate were optimized to enable it to have excellent vibration reduction performance under different wave periods and mooring methods.

[0041] The multilayer porous plate structure of the present invention mainly includes a multilayer porous plate, a fixing device and an elastic float that can be optionally used. The absolute dimensions involved in the multilayer porous plate structure described below are all model dimensions, and the prototype dimensions can be scaled according to the actual scale.

[0042] Multilayer porous plate

[0043] like Figure 1 As shown, the multi-layer porous plate is the core vibration reduction structure of the present invention, which can effectively reduce the transmission of wave energy and reduce the hydroelastic response and the maximum mooring force by optimizing the number of porous plate layers, plate spacing, porosity and installation position, combined with VLFS.

[0044] In general, a multi-layer porous plate is formed by vertically stacking several layers of porous plates, each layer of which has evenly distributed openings and is fixed together by rigid or elastic connectors. The arrangement of the multi-layer porous plate includes single-sided installation (wave-facing side) and double-sided installation (wave-facing side and wave-back side). Specifically, its performance is significantly affected by porosity, plate spacing, number of layers and water immersion depth. This embodiment describes in detail the design, parameter optimization and installation method of the multi-layer porous plate.

[0045] Design of perforated plate

[0046] In this embodiment, the porous plate is made of high-strength lightweight material, and has evenly distributed circular openings on its surface, which are used to introduce additional resistance and dissipate wave energy during wave propagation.

[0047] In some embodiments, the material of the porous plate is acrylic plate, polycarbonate plate or other composite materials resistant to marine environment. As an option, a metal composite material with better corrosion resistance can be selected according to actual engineering needs to improve the durability of the structure.

[0048] like Figure 2 As shown, specifically, the diameter of the openings on the surface of the porous plate is between 5 mm and 30 mm, and the porosity is controlled between 6% and 15%.

[0049] The structure of multi-layer porous plate

[0050] In this embodiment, the multi-layer porous plate structure is composed of 2 to 4 layers of horizontally stacked porous plates. The porous plates are kept at a fixed distance by brackets or connectors, while allowing necessary adjustments.

[0051] As an option, the plate spacing is designed to be 4.2% to 16.7% of the working water depth of the floating body. Generally speaking, a smaller plate spacing is suitable for short-wave waves and can more effectively dissipate high-frequency wave energy; a larger plate spacing is suitable for long-wave wave conditions and helps improve the vibration reduction performance in long-wave propagation.

[0052] In a possible implementation, the aperture plates are connected by a plurality of stainless steel screws.

[0053] Installation method and water depth

[0054] In this embodiment, the multi-layer porous plate is installed on the wave-facing side and / or the wave-receiving side of the VLFS through a rigid or elastic connector. Specifically, the installation methods include the following:

[0055] As an option, the perforated plate can be fixed in a number of ways, including bolt fixing, slide rail adjustment and elastic support. Bolt fixing can ensure the rigid stability of the perforated plate; slide rail adjustment allows flexible adjustment of the horizontal position and water depth; elastic support further optimizes the vibration reduction performance by absorbing impact force.

[0056] In general, the immersion depth of the porous plate is designed to be 1 to 3 times the wave height below the bottom of the floating body. Selecting an appropriate immersion depth can improve the wave dissipation effect of the multi-layer porous plate structure. Usually, the optimal immersion depth of the porous plate is between 1 to 3 times the wave height below the bottom of the floating body.

[0057] In some embodiments, the distance between the front horizontal position of the aperture plate on the wave-facing side and the front of the floating body can be adjusted to 0.25 to 1 times the length of the aperture plate. When installed on both sides, the horizontal position of the aperture plate on the back wave side can be adjusted according to the wavelength, so that it plays a role in optimizing the response on the back wave side.

[0058] In this embodiment, the parameter design of the multilayer porous plate combines the results of laboratory physical model tests and actual engineering requirements, and specifically includes the following optimization schemes:

[0059] As a possible optimization method, the best value of porosity in different wavelength ranges can be selected as:

[0060] Short-wave band (wavelength to float length ratio is less than or equal to 0.3): porosity is recommended to be 10% to 15%;

[0061] Long wave band (wavelength to float length ratio greater than 0.3): porosity is recommended to be 6% to 10%.

[0062] In general, the optimal range of the plate spacing is 4.2% to 16.7% of the working water depth of the float, and the optimal value is closely related to the ratio of the wavelength to the length of the float. The water entry depth ranges from 1 to 3 times the wave height below the bottom of the float, and its selection is affected by the wave period and the size of the float.

[0063] In one possible implementation, the multi-layer porous plates can also be combined with a real-time adjustment system to dynamically adjust the plate spacing and water entry depth through electric slides and sensors to adapt to different wave conditions. Real-time adjustment can further improve the vibration reduction performance of the structure and expand its scope of application.

[0064] Fixtures

[0065] The fixing device is a key connecting component between the multi-layer porous plate structure and the very large floating structure (VLFS) of the present invention, and its design has an important influence on the vibration reduction performance and installation flexibility of the porous plate. Through the fixing device, the porous plate can be firmly connected to the wave-facing side or / and the wave-back side of the VLFS, and necessary adjustments are allowed to adapt to different wave conditions and engineering requirements.

[0066] In general, the fixing device needs to meet the requirements of rigid connection and elastic adjustment at the same time, so as to ensure the stability of the porous plate and flexibly adjust the horizontal position, water immersion depth and other parameters of the porous plate. Specifically, the fixing device includes a bolt fixing component, a slide rail adjustment component and an elastic support component, which can meet various installation requirements of the multi-layer porous plate. This embodiment describes the design and working method of the fixing device in detail.

[0067] Bolt-on components

[0068] In this embodiment, the bolt fixing assembly is used to achieve a rigid connection between the multi-layer porous plate and the VLFS, and is suitable for use when the waves are relatively stable or the vibration reduction parameters are fixed.

[0069] Typically, bolt-on assemblies are made of high-strength stainless steel bolts and nuts, which are corrosion-resistant and fatigue-resistant. As an option, the connection points between the perforated plate and the VLFS can be pre-drilled to facilitate quick installation or replacement of the perforated plate.

[0070] In some embodiments, the bolt fixing assembly is used in conjunction with a gasket or a rubber support to further reduce the impact of vibration on the connection components and improve the impact resistance of the aperture plate.

[0071] In one embodiment, a pair of U-shaped connectors are installed on the end side of the VLFS model, and the screw holes on the U-shaped connectors can be connected to the porous plate structure, so that the porous plate structure is fixed directly below the VLFS model. Figure 3 and Figure 4 The figure shows the dimensions of the connector and its installation position on the VLFS model.

[0072] Specifically, the bolt fixing assembly is suitable for the installation of the perforated plates on the wave-facing side and the wave-back side of the VLFS, and different bolt specifications and spacings can be designed according to needs. For example, for the perforated plates on the wave-facing side, a larger bolt diameter and a dense arrangement can be used first; for the perforated plates on the wave-back side, the number of connection points can be appropriately reduced to optimize the overall weight.

[0073] Slide rail adjustment assembly

[0074] In this embodiment, the slide rail adjustment assembly is used to achieve flexible adjustment of the horizontal position and the water entry depth of the aperture plate, and is suitable for use in scenarios where wave conditions are changeable or the vibration reduction performance needs to be optimized.

[0075] In a possible implementation, the slide rail adjustment assembly includes a fixed slide rail, a sliding block and a locking mechanism. The fixed slide rail is installed on the wave-facing side or wave-back side surface of the VLFS, the sliding block realizes horizontal sliding or vertical lifting of the aperture plate through the slide rail, and the locking mechanism is used to lock the aperture plate after adjusting to the target position.

[0076] Generally, the rail adjustment assembly is made of corrosion-resistant aluminum alloy or stainless steel to ensure its long-term reliability. The guide rail part of the rail can be designed as a flat rail or a grooved rail, and the sliding block is equipped with rollers or sliders to reduce sliding friction. As an option, the rail adjustment assembly can also be combined with an electric drive device to automatically adjust the horizontal position and immersion depth of the aperture plate by monitoring the wave conditions through sensors.

[0077] Elastic support components

[0078] In this embodiment, the elastic support assembly is used to absorb the impact caused by the wave force while fixing the porous plate, and is suitable for use in scenes with severe wave conditions or where the impact resistance of the porous plate needs to be improved.

[0079] Generally, the elastic support assembly is composed of an elastic pad, a spring or a rubber support, and the elastic element is connected between the aperture plate and the VLFS by bolts or welding. In some embodiments, the elastic support assembly can be designed as a multi-segment structure to disperse the impact force and improve its energy absorption capacity.

[0080] As an option, the elastic support assembly can be used in conjunction with the slide rail adjustment assembly, which not only realizes the adjustment function of the aperture plate, but also enhances the impact resistance of the aperture plate. For example, in the seabed anchor chain mooring mode, the elastic support assembly can absorb the vertical component of the wave force, thereby reducing the additional load on the VLFS; in the mooring bollard mooring mode, the elastic support assembly can reduce the impact force of the floating body movement on the aperture plate.

[0081] In some embodiments, the design of the fixture can be optimized in combination with the specific parameters of the multi-layer porous plate. For example:

[0082] As a possible optimization method, the adjustment range of the slide rail adjustment assembly can be dynamically adjusted according to the wave conditions:

[0083] The sliding range of the horizontal slide rail can be designed to be 10% to 30% of the length of the float to meet the optimization requirements of different wave wavelengths;

[0084] The adjustment range of the vertical slide rail can be designed to be 1 to 3 times the wave height to optimize the adjustment effect of the water entry depth.

[0085] Generally, the bolt diameter of the bolt fixing assembly can be selected between 10 mm and 20 mm according to the size and material of the aperture plate, and used in conjunction with an anti-loosening gasket.

[0086] As an extended design, the fixture can be combined with a real-time adjustment system to drive the slide assembly through a servo motor and combine it with sensor feedback to achieve automatic adjustment of the position of the aperture plate to adapt to complex wave environments.

[0087] Elastic float

[0088] like Figure 5 As shown, the elastic buoy is an optional component in the multi-layer porous plate structure of the present invention, which is used to further enhance the vibration reduction performance of the porous plate. By arranging the elastic buoy between the multi-layer porous plates, the component can effectively dissipate wave energy and provide elastic support and additional resistance to the porous plates, thereby improving the control effect of the hydroelastic response.

[0089] Generally, the elastic buoy is fixed to the multi-layer porous plate through a fishing net or a frame, and is suitable for different wavelength ranges under the action of regular waves and irregular waves. Specifically, the diameter, material, density and arrangement of the elastic buoy have a significant impact on its vibration reduction effect. This embodiment describes the design, parameters and implementation of the elastic buoy in detail.

[0090] Design of elastic float

[0091] In this embodiment, the elastic buoy is made of high-elastic rubber or similar materials with a density close to that of water, and can produce elastic deformation under wave impact and dissipate energy through a deformation recovery process.

[0092] As an option, the diameter of the elastic buoy is designed to range from 20 mm to 50 mm. Generally speaking, the elastic buoy with a smaller diameter is suitable for the energy dissipation requirements of short-wavelength waves, while the elastic buoy with a larger diameter is better for the energy dissipation effect of long-wavelength waves.

[0093] In some embodiments, the material of the elastic float can be a rubber material with good corrosion resistance and aging resistance, and the material can be treated with seawater corrosion protection or anti-ultraviolet additives can be added according to specific environmental conditions to enhance its applicability and service life.

[0094] Specifically, the density of the elastic float is preferably 0.95 g / cm 3 Up to 1.05g / cm 3 , slightly lower than or close to the density of water to ensure that the float does not affect the buoyancy of the structure in water and maintains stable elastic recovery performance.

[0095] Arrangement of elastic float

[0096] In this embodiment, the elastic floating ball is fixed between adjacent porous plates through a fishing net or a frame to form a floating ball-porous plate combined structure. The arrangement of the floating ball has a significant impact on its vibration reduction performance.

[0097] As an option, the elastic buoys can be evenly distributed in the fishing net or frame, and the spacing between the buoys is preferably 2 to 5 times the diameter of the buoys. Generally, a smaller spacing can enhance the collision effect between the buoys, while a larger spacing is more conducive to the fluid exchange between the wave and the porous plate.

[0098] In some embodiments, the arrangement position of the buoys can be adjusted according to the wave direction and strength. For example, dense buoys are preferentially arranged between the perforated plates on the wave-facing side to improve the wave energy dissipation effect on the wave-facing side; while the number of buoys is appropriately reduced between the perforated plates on the wave-back side to reduce the obstruction to the fluid flow.

[0099] Specifically, when the elastic buoy is arranged in the middle layer of the multi-layer porous plate structure, its energy absorption performance can be maximized and the porous plate can be supported. In a possible implementation, the buoy is arranged in an area with a depth of 20% to 80% from the water surface to adapt to the energy concentration range of different wave cycles.

[0100] How to fix the elastic float

[0101] In this embodiment, the elastic float is fixedly connected to the porous plate through a fishing net or a frame. The fishing net is usually made of high-strength, corrosion-resistant polyethylene fiber, and its mesh size is preferably 0.5 to 0.8 times the diameter of the float to ensure that the float can be stably positioned in the fishing net.

[0102] In some embodiments, the fixing method of the elastic buoy can also be used in combination with a slide rail adjustment device to adjust the placement and depth of the buoy. For example, by adjusting the vertical slide rail of the frame, the placement depth of the buoy can be adjusted in real time to adapt to changes in different wave conditions.

[0103] Parameter optimization of elastic float

[0104] In this embodiment, the diameter, density and arrangement of the elastic floating balls are optimized through experiments to ensure that the vibration reduction performance under regular wave and irregular wave conditions is optimal.

[0105] Generally, the diameter of the float ranges from 20 mm to 50 mm, with a 30 mm diameter float being suitable for most wave conditions. Under regular wave conditions, the recommended float spacing is about three times its diameter; under irregular wave conditions, the spacing can be appropriately reduced to enhance the collision effect between the floats.

[0106] As a possible optimization method, the density of the buoys can be adjusted according to the wave period. For example, under short-period wave conditions, it is recommended to arrange 200 to 300 buoys per square meter; under long-period wave conditions, it is recommended to arrange 100 to 150 buoys per square meter.

[0107] Application scope of elastic float

[0108] In this embodiment, the elastic buoy is suitable for various scenarios under the action of regular waves and irregular waves, and can effectively enhance the vibration reduction performance of the multi-layer porous plate.

[0109] Under the seabed anchor chain mooring mode, the elastic buoy can reduce the vertical component of wave force, thereby optimizing the motion response of the VLFS; under the bollard mooring mode, the elastic buoy can reduce the impact force between the float and the cable, further improving the safety of the mooring system.

[0110] As an extended design, the elastic buoy can also be combined with an intelligent adjustment system to monitor wave conditions and adjust the layout density and depth of the buoy in real time to achieve more precise vibration reduction control.

[0111] In general, the present invention effectively reduces the hydroelastic response and maximum mooring force of the floating body under the action of waves by optimizing the number of porous plate layers, porosity, plate spacing and immersion depth, and combining rigid or elastic fixing devices to connect with the floating structure. The multi-layer porous plates are made of high-strength lightweight materials, and the openings are evenly distributed on the surface. Elastic buoys can be arranged between the porous plates as required to further improve the vibration reduction performance and wave energy dissipation capacity. The present invention is suitable for a variety of wave conditions and floating application scenarios. Its design has been verified by physical model tests and can meet the safety and stability requirements of ultra-large floating structures in complex marine environments, providing an efficient and flexible solution for floating vibration reduction technology.

[0112] In order to better understand the present invention, the above scheme is described in detail below in conjunction with specific embodiments.

[0113] The following examples are all carried out in the long-short period composite wave pool of the State Key Laboratory of Coastal and Offshore Engineering of Dalian University of Technology. The effective size of the pool is 40.0m×24.0m×1.2m, the maximum working water depth is 0.9m, the maximum wave height is 0.25m, and the period range is 0.5s to 5.0s. The test is based on the push-plate wave maker to generate regular waves and irregular waves, which are used to study the vibration reduction effect of the multi-layer porous plate structure in the very large floating structure (VLFS).

[0114] To ensure the similarity between the model test and the actual project, the following embodiments follow the gravity similarity criterion and the elastic similarity criterion. After multiple adjustments, a sandwich structure consisting of 2 layers of aluminum plates and 2 layers of polyethylene foam plates was used as the VLFS model. The geometric dimensions were designed with reference to the first phase of the test of the Japan Mega-Float Technology Research Association at a scale ratio of 1:50. The model is 6m long, 1.25m wide and 78mm thick. The VLFS model is arranged in the center of the pool. The experiment studies the influence of multi-layer porous plates on the VLFS hydroelastic response and mooring force under different wave conditions. Table 1 shows the main parameters of the wave and VLFS models. The material composition of the VLFS model is as follows: Figure 6 As shown in Figure 2, the VLFS model is arranged in water as follows: Figure 7 shown.

[0115] Table 1 Main parameters of wave and VLFS models

[0116] parameter Model prototype Length(m) 6 300 Width(m) 1.25 62.5 Thickness(m) 0.078 3.9 Draft(m) 0.02 1 <![CDATA[Flexural rigidity (N·m 2 )]]> <![CDATA[2.2742×10 4 ]]> <![CDATA[7.1069×10 12 ]]> Water depth(m) 0.6 30 Wavelength(m) 0.6～7.2 30～360 Mass(kg) 92 <![CDATA[1.15×10 7 ]]>

[0117] Two mooring methods are used: seabed anchor chain mooring and bollard mooring, such as Figure 8 The test model is also equipped with high-precision optical measurement equipment OptrakCertus and multi-channel wave height meters to record the motion response, wave characteristics and mooring force of the VLFS.

[0118] Embodiment 1:

[0119] This embodiment is based on the submarine anchor chain mooring method, and studies the influence of different porosities on the vibration reduction effect of the multi-layer porous plate structure. Through the analysis of the 2-layer, 3-layer and 4-layer porous plate structures, the regulation effect of the VLFS hydroelastic response and the maximum mooring force under different wavelength conditions was tested. The water immersion depth of the porous plate in this embodiment is 0.12m, the plate spacing is 0.05m, and the ratio of wavelength to VLFS length ranges from 0.1 to 1.0.

[0120] In this embodiment, by comparing and analyzing multilayer porous plates with different porosities (0.06, 0.1, 0.15), the following rules are obtained:

[0121] Effect of hydroelastic response

[0122] The multilayer porous plate structures with different porosities show consistent regularity in the variation of VLFS hydroelastic response with wavelength. When the wavelength is short (the ratio of wavelength to VLFS length is in the range of 0.1 to 0.2), the hydroelastic response decreases with increasing porosity. A larger porosity is more conducive to dissipating wave energy and reducing the response amplitude of the floating body.

[0123] However, when the wavelength is in the middle range (the ratio of wavelength to VLFS length is in the range of 0.3-0.4), the hydroelastic response increases with the increase of porosity, indicating that a larger porosity will cause a larger floating body response under medium wavelength conditions. For longer wavelengths (the ratio of wavelength to VLFS length is in the range of 0.5-0.6), multilayer porous plates with different porosities can achieve the best vibration reduction effect, and the specific effect is related to the wavelength.

[0124] When the wavelength is further increased (the ratio of wavelength to VLFS length is greater than 0.6), the sensitivity of the hydroelastic response to the change of porosity decreases significantly, indicating that the porosity has little effect on the floating body response under long-wave conditions.

[0125] Influence of maximum mooring force

[0126] The influence of multi-layer porous plate structures with different porosities on the maximum mooring force of the VLFS model. For the two-layer porous plate structure, when the porosity is P = 0.15, the maximum mooring force is the smallest, while when P = 0.1, the maximum mooring force reaches the maximum.

[0127] For the three-layer porous plate structure, when the ratio of wavelength to VLFS length is equal to 0.5, the maximum mooring force of the structure with a porosity of P = 0.15 is the largest; and when the ratio of wavelength to VLFS length is equal to 0.7, the maximum mooring force of the structure with a porosity of P = 0.06 is the largest. Under other wavelength conditions, the effects of different porosities on the maximum mooring force are relatively similar.

[0128] For the 4-layer porous plate structure, when the ratio of wavelength to VLFS length is 0.5-0.7, the maximum mooring force is the largest for the structure with a porosity of P = 0.06, while the maximum mooring force is the smallest for the structure with P = 0.15. Under other wavelength conditions, the change of porosity has little effect on the maximum mooring force.

[0129] This example shows that the choice of porosity in the multilayer porous plate structure has a significant impact on the hydroelastic response and mooring force of the VLFS. Specifically:

[0130] Larger porosity is suitable for short-wave conditions and can more effectively reduce the hydroelastic response;

[0131] Moderate porosity may induce higher hydroelastic responses in certain wavelength ranges;

[0132] The porosity has less effect on long-wave conditions, but its effect on the maximum mooring force varies with the number of plies and wavelength.

[0133] In actual engineering, the appropriate porosity can be selected according to the wave conditions of the water area to optimize the vibration reduction effect within different wavelength ranges.

[0134] Embodiment 2:

[0135] This example studies the influence of multi-layer porous plate structures with different porosities on the hydroelastic response of VLFS and the maximum mooring force under the bollard mooring mode. In the example, 2-layer, 3-layer and 4-layer porous plate structures were used to analyze their vibration reduction effect and mechanical properties within the ratio of wavelength to VLFS length equal to 0.1 to 1.0. The test parameters include the immersion depth of 0.12m and the plate spacing of 0.1m (2-layer structure) and 0.05m (3-layer and 4-layer structures).

[0136] Effect of hydroelastic response

[0137] The influence of different porosities on the hydroelastic response shows a significant regularity with the change of wavelength:

[0138] When the ratio of wavelength to VLFS length is 0.1-0.2, the hydroelastic response of VLFS decreases with the increase of porosity. At this time, higher porosity (0.1 or 0.15) can dissipate wave energy more efficiently and reduce the response amplitude on the wave-facing side.

[0139] When the ratio of wavelength to VLFS length is 0.3-0.5, the hydroelastic response on the wave-facing side increases with the increase of porosity, while the response on the wave-back side does not change much. This indicates that under medium-wavelength conditions, larger porosity may lead to higher fluid resistance and cause larger floating body deformation.

[0140] When the ratio of wavelength to VLFS length is greater than 0.5, the sensitivity of the hydroelastic response to porosity decreases significantly, indicating that under long-wave conditions, the porosity of the porous plate has limited influence on the vibration reduction effect.

[0141] The experiment also shows that the influence of 2-layer, 3-layer and 4-layer porous plate structures on the hydroelastic response is similar, but the increase in the number of layers will enhance its effect on the wave-facing side.

[0142] Influence of maximum mooring force

[0143] Effect of different porosity on the maximum mooring force of VLFS:

[0144] For the two-layer porous plate structure, when the ratio of wavelength to VLFS length is less than or equal to 0.4, the maximum mooring force is smaller than that of the structure without porous plate, indicating that a larger porosity can effectively reduce the peak value of the mooring force; when the ratio of wavelength to VLFS length is greater than 0.4, the presence of the porous plate will increase the peak value of the mooring force.

[0145] For the 3-layer and 4-layer porous plate structures, when the ratio of wavelength to VLFS length is less than or equal to 0.6, the maximum mooring force is less than or close to the case without porous plates; when the ratio of wavelength to VLFS length is greater than 0.6, the maximum mooring force increases significantly with the increase of the number of porous plate layers.

[0146] Experiments show that 3-layer and 4-layer porous plate structures may cause large additional forces under long-wave conditions, and need to be optimized by comprehensively considering engineering requirements.

[0147] This example shows that different porosities have a significant effect on the hydroelastic response and maximum mooring force of the VLFS. Specifically:

[0148] The optimization of porosity needs to be determined according to the wavelength range: under short-wave conditions, a larger porosity (such as 0.15) has a better effect; under medium-wave conditions, a smaller porosity (such as 0.06) has a better effect; under long-wave conditions, the porosity has little effect on the vibration reduction effect.

[0149] In terms of the maximum mooring force, the porosity has little effect on short-wave and medium-wave conditions, but has a significant impact on long-wave conditions. It is necessary to reasonably select the combination of the number of layers and porosity to reduce the additional mooring force.

[0150] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-layer porous plate structure for shock absorption of super-large floating bodies, characterized in that: The invention comprises a plurality of horizontally arranged porous plates, which are interconnected to form a multi-layer porous plate structure, each of which is made of a high-strength lightweight material, and the surface of the porous plate is provided with evenly distributed openings, and the multi-layer porous plates are connected to the super-large floating structure through a fixing device, so as to reduce the hydroelastic response of the floating body and the maximum mooring force, wherein: The porosity of the porous plate is 6% to 15%. The number of porous plate layers is 2 to 4. The spacing between adjacent porous plates is 4.2% to 16.7% of the working water depth of the floating body. The immersion depth of the porous plate is 1 to 3 times the wave height below the bottom of the floating body.

2. A multi-layer porous plate structure for shock absorption of a super-large floating body according to claim 1, characterized in that: The porous plate is a light and high-strength material, including an acrylic plate or a polycarbonate plate.

3. The multi-layer porous plate structure for shock absorption of a super-large floating body according to claim 1, characterized in that: The horizontal position of the aperture plate can be adjusted, specifically: The distance between the front position of the porous plate on the wave-facing side and the front position of the floating body model is 0.25 to 1 times the length of the porous plate; The rear edge position of the aperture plate on the back-wave side can be adjusted toward the wave-facing direction or the back-wave direction of the floating body according to the wavelength, and the adjustment range is 0.25 times to 1 times the length of the aperture plate.

4. The multi-layer porous plate structure for shock absorption of a super-large floating body according to claim 1, characterized in that: The connection mode between the aperture plate and the floating body is a rigid connection or an elastic connection, which is fixed by bolts, adjustable installation of slide rails or elastic support to adapt to different wave frequencies and mooring modes.

5. The multi-layer porous plate structure for shock absorption of a super-large floating body according to claim 1, characterized in that: The multi-layer porous plate structure is installed on the wave-facing side or both the wave-facing side and the wave-receiving side of the floating body. When installed on both sides, the porosity and the number of layers of the porous plates on the wave-facing side and the wave-receiving side can be adjusted respectively to optimize the vibration reduction effect on the wave-facing side and the wave-receiving side.

6. The multi-layer porous plate structure for shock absorption of a super-large floating body according to claim 5, characterized in that: An elastic buoy is arranged between adjacent porous plates on the wave-facing side or the wave-back side. The elastic buoy is fixed between adjacent porous plates through a fishing net or a frame structure. The elastic buoy is made of rubber with a density close to that of water.

7. The multi-layer porous plate structure for shock absorption of a super-large floating body according to claim 1, characterized in that: The multi-layer porous plate structure is suitable for a floating system using a seabed anchor chain mooring method or a mooring bollard mooring method, specifically: In the submarine anchor chain mooring mode, the double-side installation mode is adopted; In the bollard mooring mode, the single-side installation mode on the wave-facing side is adopted.

8. The multi-layer porous plate structure for shock absorption of a super-large floating body according to claim 1, characterized in that: The multi-layer porous plate structure adjusts the wave reflection coefficient, transmission coefficient and energy dissipation coefficient of the floating body by changing the porosity, plate spacing, number of layers, horizontal position and water immersion depth of the porous plate to adapt to different marine environments and wave conditions.

9. The multi-layer porous plate structure for shock absorption of a super-large floating body according to claim 1, characterized in that: The multi-layer porous plate structure can reduce the maximum value of the hydroelastic response of the wave-facing side and the wave-rear side of the floating body under the wave condition where the ratio of the wavelength to the floating body length is less than 0.3; under the wave condition where the ratio of the wavelength to the floating body length is greater than 0.3, the vibration reduction effect is concentrated on the wave-facing side of the floating body.

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