Prestressed self-locking connection node of offshore floating platform based on bamboo winding composite material

Abstract

The invention belongs to the technical field of ocean floating photovoltaic power generation, and discloses an ocean floating platform prestress self-locking connecting node based on a bamboo winding composite material, which comprises an upper connecting piece which is a hollow component made of anti-corrosion steel, a square hole is formed in the center of the bottom of the upper connecting piece, and four flattened areas are arranged on the side wall of the upper connecting piece; the lower connecting piece is a hollow component made of anti-corrosion steel, the top of the lower connecting piece is closed, and the side wall of the lower connecting piece is provided with four flattened areas; and the rubber gasket is arranged between the upper connecting piece and the lower connecting piece and applies axial tensioning force to the CFRP plate through the end anchoring system and the jack loading device. The tensioned CFRP plate forms a stable longitudinal prestress field on the outer side of the connecting piece, the stress is transmitted through a structural bonding interface of the bamboo winding composite pipe, a splicing area is kept in a continuous pressing state, the joint tensile strength and the overall rigidity are enhanced, and the joint strength is improved. Cracking, sliding or fatigue accumulated damage caused by external disturbance loads such as waves, wind loads and buoyancy changes is effectively prevented.

Description

Technical Field

[0001] This invention belongs to the field of marine floating photovoltaic power generation technology, specifically a prestressed self-locking connection node for a marine floating platform based on bamboo-wound composite material. Background Technology

[0002] With the continued growth of global demand for renewable energy, solar photovoltaic power generation has become an important form of green energy. In recent years, offshore floating photovoltaic systems have gradually become an important development direction for photovoltaic technology due to their advantages of not occupying land resources, having good heat dissipation, and high power generation efficiency.

[0003] However, existing offshore floating platforms still face numerous challenges in terms of buoyancy support, wave resistance, and long-term durability. Traditional floating structures mostly use high-density polyethylene (HDPE) and other polymer materials, which, while possessing certain buoyancy and corrosion resistance, are prone to UV aging, salt spray corrosion, and fatigue cracking in long-term marine environments, affecting platform stability and system lifespan. Simultaneously, existing connection nodes largely rely on traditional methods such as bolts and welding, which are susceptible to loosening and fatigue damage under the multiple dynamic effects of waves, tides, and wind loads, making it difficult to meet the stability and safety requirements for long-term service.

[0004] In recent years, bamboo-wound composite materials have emerged as a promising new material for marine structures due to their high specific strength, excellent corrosion resistance, and environmentally friendly characteristics. They possess superior mechanical properties, strong environmental adaptability, and a significantly lower carbon footprint than traditional materials, making them a potential replacement for plastic floats and driving the green transformation of marine floating structures. However, bamboo-wound composite pipes still lack efficient and reliable connection solutions for longitudinal splicing and connection node design, and traditional connection methods struggle to achieve rapid installation and stable connections under dynamic loads.

[0005] This invention proposes a prestressed self-locking connection node for offshore floating platforms based on bamboo-wound composite materials, which can significantly improve the structural connection performance and platform operation reliability, providing a high-performance green connection solution for offshore floating photovoltaic systems. Summary of the Invention

[0006] The purpose of this invention is to address the above-mentioned problems. This invention provides a prestressed self-locking connection node for offshore floating platforms based on bamboo-wound composite materials, which has the advantages of easy installation, self-locking stability, durable sealing, and modular assembly.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a prestressed self-locking connection node for a floating platform based on bamboo-wound composite material, including an upper connector, which is a hollow component made of corrosion-resistant steel, with a square hole at the bottom center and four flattened areas on the side wall; The lower connector is a hollow component made of corrosion-resistant steel, with a closed top and four flattened areas on the side walls; A rubber gasket is disposed between the upper connector and the lower connector; The locking piece engages with the square hole of the upper connector to achieve axial self-locking; A spring, with the locking plate connected to one end, is used to drive the locking plate to automatically reset; An angle fitting is welded to the lower connector, and the end of the spring away from the locking plate is connected to the angle fitting to fix the spring and the locking plate; CFRP sheets are laid along the flattened area and subjected to longitudinal prestress via an anchoring-tensioning device to provide continuous clamping force.

[0008] Preferably, the outer walls of the upper connector and the lower connector are bonded to the inner wall of the bamboo-wound composite pipe using a two-component marine-grade structural adhesive.

[0009] Preferably, the rubber gasket is made of a seawater-resistant, high-resilience elastomer material.

[0010] Preferably, the locking plate is made of stainless steel or carbon fiber reinforced composite material and is provided with a limiting protrusion.

[0011] Preferably, the spring is made of stainless steel or a seawater-resistant elastic alloy, and its compression stroke matches the movement stroke of the locking plate.

[0012] Preferably, the corner fitting is in the shape of a hollow cross-shaped through-groove column, used to accurately position the springs from four directions and prevent rotational slippage.

[0013] Preferably, it also includes a CFRP sleeve, which circumferentially covers the connection area and is sealed with structural adhesive after the node assembly is completed.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Axial tension is applied to the CFRP plate through the end anchoring system and jack loading device. After tensioning, the CFRP plate forms a stable longitudinal prestress field on the outside of the connector. This stress is transferred through the structural bonding interface with the bamboo-wound composite pipe, keeping the splicing area in a continuously compressed state. This compressive force not only enhances the tensile strength and overall stiffness of the joint, but also effectively prevents cracking, slippage, or fatigue accumulation failure caused by external disturbance loads such as waves, wind loads, and buoyancy changes. After tensioning is completed and the tensioning device is unloaded, the CFRP plate further generates continuous centripetal and longitudinal clamping forces due to the material shrinkage effect, providing stable reaction support for subsequent mechanical self-locking actions, thereby significantly improving the joint's pull-out resistance and service stability.

[0015] 2. During the tensioning process of the CFRP sheet, the upper section of the bamboo-wound composite pipe and the upper connector are simultaneously inserted axially into the lower connector. During insertion, the square hole at the bottom of the upper connector gradually presses down the locking plate assembly pre-installed in the lower connector. As the insertion depth increases, the locking plate automatically springs up and locks into the hole under the action of the spring return force, achieving rapid and high-strength mechanical locking. The top of the locking plate is equipped with a limiting boss, which can form a meshing fit with the hole wall, constructing a reliable axial anti-reverse mechanism to prevent the node from springing off due to vibration or tension during use. At the same time, the spring ensures that the locking plate remains in a continuously locked state under dynamic loads (such as waves, tides, wind pressure, etc.), realizing the self-positioning, self-resetting, and self-holding functions of the node.

[0016] 3. After the node is installed, a layer of CFRP composite sleeve is laid around its exterior and sealed with structural adhesive to achieve dual reinforcement of structure and protection. This sleeve has the following key functions: circumferentially covering the node with high-strength composite material to effectively resist wave impact or collision; working in conjunction with the CFRP prestressed plate to improve the bending stiffness and torsional resistance of the connection area; effectively sealing the connection cavity to block the erosion paths of seawater, ultraviolet rays, and biofouling, significantly delaying the corrosion process of the node structure; the material has good UV resistance, anti-aging, and antimicrobial properties, requiring no frequent maintenance, and is especially suitable for applications with extremely high requirements for long-term node stability, such as offshore and unattended photovoltaic platforms.

[0017] 4. The prestress of the CFRP plate and the locking force of the locking plate are dynamically adjusted according to the actual working conditions identified by the system to avoid the nodes being in an overstressed or understressed state for a long time. Fatigue tests have verified that this can extend the fatigue life of the nodes after integrated intelligent control, and form a synergy with the long-term durability of bamboo-wound composite materials to further improve the overall service life of the platform. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall structure of the present invention; Figure 3 This is a schematic diagram of the installation process of the present invention; Figure 4 This is a schematic diagram of the connection structure before the CFRP board of the present invention is installed; Figure 5 This is a schematic diagram of the connection structure after the CFRP board of the present invention is installed; Figure 6 This is a schematic diagram of the connection structure during the connection process of the CFRP board of the present invention.

[0019] Attached Figure Descriptions: 1. Upper Connector; 2. Lower Connector; 3. Rubber Washer; 4. Locking Plate; 5. Spring; 6. Angle Fittings; 7. CFRP Sheet; 7-1. Force Transmission Component; 7-2. Fixing Device; 7-3. Jack; 7-4. Anchor Head; 8. CFRP Sleeve. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1 like Figures 1-6 As shown, the prestressed self-locking connection node of the offshore floating platform based on bamboo-wound composite material includes an upper connector 1, which is made of corrosion-resistant steel and has a hollow internal structure. A square hole is provided at the center of its bottom, which is used to engage with the locking plate 4 to form a self-locking connection during the splicing process.

[0022] The side wall of the upper connector 1 has four flattened areas to reserve installation space for the prestressed CFRP plate 7; The lower connector 2 is made of corrosion-resistant steel and has a hollow internal structure. Its top is closed and it is connected to the corner fitting 6 by welding. The side wall of the lower connector 2 also has four flattened areas to provide installation space for the laying and anchoring of the CFRP board 7. Rubber gasket 3 is set between the upper connector 1 and the lower connector 2 as an elastic seal and buffer component to improve the water tightness of the joint and absorb vibration and mitigate impact under ocean dynamics such as waves and wind loads, thereby improving the connection stability under complex ocean working conditions such as waves and wind loads. Locking piece 4 engages with the square hole inside the upper connector 1 to achieve axial self-locking and anti-reverse function of the node; Spring 5 is connected to locking plate 4 at one end and corner fitting 6 at the other end. Through elastic extension and contraction, it drives locking plate 4 to complete automatic reset and locking, enhancing the impact and vibration resistance of the connection node. Angle fitting 6 is used to fix springs 5 ​​and locking plates 4 in multiple directions. Its bottom is connected to the lower connector 2 by welding, which plays a role in accurately positioning the position of springs 5 ​​and integrating the whole, ensuring that the connection node maintains structural stability under multi-directional force.

[0023] Furthermore, the flattened areas of the sidewalls of the upper connector 1 and the lower connector 2 are rectangular planes, and their outer walls are bonded to the inner wall of the bamboo-wound composite pipe with a two-component marine-grade structural adhesive to form a strong and reliable connection interface, ensuring the force transmission efficiency and durability between the upper connector 1, the lower connector 2 and the bamboo pipe.

[0024] Furthermore, the rubber gasket 3 is made of a high-resilience elastomer material that is resistant to seawater corrosion, and has long-term resistance to compression deformation, UV aging and fatigue, making it suitable for long-term use in marine high-humidity and high-salt-spray environments.

[0025] Furthermore, the locking plate 4 is made of stainless steel or carbon fiber reinforced material, and has a limiting protrusion structure on its surface. It is inserted into the square hole at the bottom of the upper connector 1 and forms a self-locking fit with the hole wall to realize the automatic locking and anti-slip function of the node.

[0026] Furthermore, the spring 5 is made of stainless steel or other corrosion-resistant elastic alloy materials, which have high resilience and long-term resistance to seawater corrosion. It can maintain reliable elastic output under long-term exposure to moisture, salt spray and wave vibration. The compression stroke matches the movement stroke of the locking plate 4 to ensure that the locking plate 4 can be quickly positioned and maintain a stable locking state during installation.

[0027] Furthermore, the corner fitting 6 is a hollow column structure with a cross-shaped through groove arrangement, which is used to accurately position the springs 5 ​​from four directions to ensure that the elastic force is evenly distributed. At the same time, it works in conjunction with the corresponding groove on the inner wall of the upper connector 1 to prevent rotational slippage.

[0028] Furthermore, the CFRP plate 7 is a prestressed carbon fiber plate made by pultrusion process. It is laid out along the outer side of the flattened area of ​​the upper and lower connectors 12, and longitudinal prestress is applied through the end anchoring and tensioning device to provide stable axial clamping force, so as to assist the positioning of the locking plate 4 and the sealing and clamping of the rubber gasket 3, and to improve the structural stability, pull-out resistance and durability of the joint.

[0029] In use, insert the upper connector 1 and the lower connector 2 into the inner cavities of the corresponding upper and lower sections of the bamboo-wound composite pipe, respectively, and bond them together at the contact interface using a two-component marine-grade structural adhesive. To ensure a strong and reliable bond, the outer surface of the connector should fit tightly against the inner wall of the bamboo pipe to avoid gaps. The outer wall of each connector has four flattened areas for the placement of the CFRP sheet 7 and subsequent tensioning and anchoring operations.

[0030] Subsequently, the locking plate 4, spring 5, and corner fitting 6 are pre-assembled. The locking plate 4 is fitted onto the corner fitting 6 through a limiting groove. One end of the spring 5 locks the locking plate 4, and the other end is inserted into the pre-set insertion hole of the corner fitting 6, keeping the locking plate 4 in a pre-positioned state when not under force. The top limiting boss of the locking plate 4 mates with the square hole at the bottom of the upper connector 1, which is reserved for automatic locking during subsequent insertion.

[0031] After completing the above structural assembly, insert the CFRP plate 7 into the open end of the bamboo-wound composite pipe, passing axially along the inner wall of the pipe through the flattened area of ​​the upper and lower connectors. Subsequently, pre-embedded holes are opened in the wall of the bamboo-wound composite pipe, chemical anchor fixing device 7-2 is installed, and epoxy resin anchoring adhesive is injected between the anchor and the bamboo pipe to form a reliable anchoring interface.

[0032] The CFRP plate is connected to the fixing device 7-2 via the anchor head 7-4. The tensioning end is equipped with a jack 7-3 and a force transmission component 7-1 to apply axial prestress to the CFRP plate.

[0033] During the tensioning process of CFRP plate 7, as the axial tension gradually increases, the upper bamboo-wound composite tube drives the upper connector 1 to be pressed into the lower connection node area along the axial direction, so that the bottom structure presses down the locking piece 4 which is in the predetermined position.

[0034] Once pressed into the designed position, the locking piece 4 automatically pops out under the restoring force of the spring 5 and locks into the square hole at the bottom of the upper connector 1, achieving synchronous completion of the self-locking action and the tensioning process of the CFRP plate 7. This design ensures that the locking piece 4 is positioned in place during the tensioning process, improving the efficiency and reliability of node splicing.

[0035] After tensioning, the CFRP plate 7 provides continuous longitudinal clamping force on the outside of the connector due to elastic recoil, which, together with the locking force of the locking plate 4, enhances the node's resistance to pull-out and structural stability.

[0036] Meanwhile, the rubber gasket 3 is pressed between the upper and lower connecting parts during the splicing and tightening process, forming an effective sealing layer that has both buffering and waterproofing functions, which can significantly improve the service performance of the node under complex working conditions such as wave impact and tidal vibration.

[0037] To further enhance the external protection of the nodes, after installation, CFRP sleeves 8 can be used to circumferentially cover the connection node area and then sealed and fixed with structural adhesive.

[0038] At room temperature, the curing time for structural adhesive and rebar adhesive is generally 24 hours. After curing, the joint can be put into use and has good strength, protection and durability.

[0039] Example 2 During use, traditional nodes cannot detect in real time the prestress loss, locking mechanism loosening or sealing failure caused by factors such as wave impact, tidal load, and temperature changes. Repairs are often carried out only after obvious damage to the structure, which can easily lead to platform shutdown or even safety accidents. On the other hand, the dynamic randomness of the marine environment requires nodes to have dynamic adaptability, while traditional mechanical connections can only rely on the preset structural strength to resist the load and cannot adjust the stress state according to the actual working conditions.

[0040] Fiber Bragg grating sensors are then used, which are arranged at intervals along the length of the CFRP board 7, i.e., 2 to 3 measuring points are arranged on each CFRP board 7. After the sensors are encapsulated in polytetrafluoroethylene that is resistant to high temperature and seawater corrosion, they are attached and fixed to the surface of the CFRP board 7.

[0041] This sensor can collect longitudinal strain data of CFRP plate 7 in real time, calculate the current prestress value of the node through strain-prestress conversion algorithm, and monitor the prestress loss caused by material creep, temperature change or load impact. The measurement accuracy can reach ±5με. The sampling frequency can be adjusted by remote command according to the working conditions. In this invention, 1Hz is used.

[0042] Simultaneously, a miniature Hall effect sensor is adopted, embedded in the inner wall of the square hole at the bottom of the upper connector 1, corresponding to the limiting protrusion position of the locking piece 4. A magnetic element is built into the limiting protrusion position. When the locking piece 4 is engaged, the limiting protrusion and the Hall sensor form a stable magnetic field coupling, and the sensor outputs a high-level signal. If the locking piece 4 becomes loose or displaced due to vibration or corrosion, the magnetic field coupling state changes, and the sensor outputs a low-level or pulse signal to provide real-time feedback on the working status of the locking mechanism, that is, the working status of the locking piece 4, the spring 5, and the corner fitting 6, ensuring that the response time is ≤10ms and avoiding node failure due to the slippage of the locking piece 4.

[0043] Miniature humidity sensors and pressure sensors are respectively installed on the two end faces of the rubber gasket 3 along its length. The humidity sensor uses a capacitive corrosion-resistant probe to monitor whether seawater seeps into the sealing area; the pressure sensor uses a piezoresistive microchip to monitor the change in the clamping force of the rubber gasket 3, thereby reflecting the degree of contact between the sealing surfaces. When the clamping force is lower than 80% of the design threshold, it is judged that the sealing performance has deteriorated, and control measures need to be initiated.

[0044] Platinum resistance sensors are used, which are embedded in the inner wall of the bamboo-wound composite pipe and the outer side of the CFRP sleeve 8, respectively, to monitor the ambient temperature and structural temperature around the node. This is to avoid stress concentration caused by thermal expansion and contraction of materials due to sudden temperature changes, and to provide temperature correction parameters for the prestress compensation algorithm of CFRP plate 7.

[0045] A miniature data acquisition unit is set up near the node, using a low-power MCU as its core. It connects to each sensor via an SPI bus to achieve real-time data acquisition, filtering, and preliminary analysis. The acquisition unit has a built-in storage module that can cache monitoring data for 72 hours. It also has a data anomaly threshold judgment function, such as CFRP board 7 prestress loss exceeding 10%, lock plate 4 abnormal status, and excessive humidity in the sealing area of ​​rubber gasket 3. When the monitored value exceeds the preset threshold, a local audible and visual alarm is immediately triggered.

[0046] When the node is running normally, the sensor collects data at a frequency of 1Hz. The data collector summarizes the data every 5 minutes and uploads it to the cloud platform. The cloud platform updates the node's digital twin model in real time. When the monitored values ​​are within the normal range, the node maintains its normal operating status.

[0047] When the prestress of CFRP plate 7 drops by 15%, the signal of locking plate 4 fluctuates, and the humidity in the area of ​​rubber gasket 3 exceeds 90%RH, abnormal data is detected. The data acquisition unit immediately triggers high-frequency acquisition, increases the sampling frequency to 10Hz, and prioritizes uploading the abnormal data to the cloud. The cloud platform activates the fault diagnosis algorithm to determine the fault type in a short time. If it is a minor fault, such as a slight loss of prestress in CFRP plate 7, it automatically sends control commands to the electric tensioning mechanism or electromagnetic push rod to complete adaptive repair. If it is a serious fault, such as the sealing failure of rubber gasket 3 or slippage of locking plate 4, it immediately pushes early warning information to the operation and maintenance center and triggers the platform's emergency protection measures.

[0048] The cloud platform generates a node health report every month, analyzing the prestress attenuation trend of CFRP board 7, the wear degree of locking plate 4 and spring 5, and the sealant consumption of rubber gasket 3 based on historical monitoring data, providing maintenance personnel with suggestions such as replenishing sealant and replacing aging spring 5; a comprehensive calibration is performed once a year, verifying the accuracy of CFRP board 7 sensor through portable on-site equipment, adjusting the parameters of the control mechanism, and ensuring the long-term reliability of intelligent control functions.

[0049] Furthermore, the prestress of CFRP plate 7 and the locking force of locking plate 4 can be dynamically adjusted according to the actual working conditions to avoid the nodes being in an overstressed or understressed state for a long time. Fatigue tests have verified that this can extend the fatigue life of the nodes after integrated intelligent control, and synergize with the long-term durability of bamboo-wound composite materials to further improve the overall service life of the platform.

[0050] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A prestressed self-locking connection node for offshore floating platforms based on bamboo-wound composite materials, characterized in that: Including the upper connector (1), which is a hollow component made of anti-corrosion steel, with a square hole in the center of the bottom and four flattened areas on the side wall; The lower connector (2) is a hollow component made of corrosion-resistant steel, with a closed top and four flattened areas on the side wall; A rubber gasket (3) is disposed between the upper connector (1) and the lower connector (2); The locking piece (4) engages with the square hole of the upper connector (1) to achieve axial self-locking; Spring (5), one end of which is connected to the locking piece (4), is used to drive the locking piece to automatically reset; Angle fitting (6) is welded to the lower connector (2), and the end of the spring (5) away from the locking piece (4) is connected to the angle fitting (6) to fix the spring (5) and the locking piece (4). CFRP plates (7) are laid along the flattened area and subjected to longitudinal prestress via anchoring tensioning devices to provide continuous clamping force.

2. The prestressed self-locking connection node for offshore floating platforms based on bamboo-wound composite material according to claim 1, characterized in that: The outer walls of the upper connector (1) and the lower connector (2) are bonded to the inner wall of the bamboo-wound composite pipe by a two-component marine-grade structural adhesive.

3. The prestressed self-locking connection node for offshore floating platforms based on bamboo-wound composite material according to claim 1, characterized in that: The rubber gasket (3) is made of a seawater-resistant, highly resilient elastomer material.

4. The prestressed self-locking connection node for offshore floating platforms based on bamboo-wound composite material according to claim 1, characterized in that: The locking plate (4) is made of stainless steel or carbon fiber reinforced composite material and is provided with a limiting protrusion.

5. The prestressed self-locking connection node for offshore floating platforms based on bamboo-wound composite material according to claim 4, characterized in that: The spring (5) is made of stainless steel or seawater-resistant elastic alloy, and its compression stroke matches the movement stroke of the locking plate (4).

6. The prestressed self-locking connection node for offshore floating platforms based on bamboo-wound composite material according to claim 1, characterized in that: The corner fitting (6) is a hollow cross-shaped through-groove column, used to accurately position the springs (5) from four directions and prevent rotational slippage.

7. The prestressed self-locking connection node for offshore floating platforms based on bamboo-wound composite material according to claim 1, characterized in that: It also includes a CFRP sleeve (8), which circumferentially covers the connection area and is sealed with structural adhesive after the node assembly is completed.

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