Pile platform structure for offshore photovoltaics

Abstract

The application discloses a pile type platform structure for offshore photovoltaics in the technical field of concrete precast pile processing, which comprises a steel pipe pile driven into seabed and a platform support for supporting photovoltaic components, the platform support comprises mutually perpendicular main beams and purlins, the platform support is fixedly connected with the upper part of the steel pipe pile through an integral wind vibration resisting connecting assembly, and the wind vibration resisting connecting assembly comprises a pile body connecting module, an auxiliary connecting module, a dynamic vibration suppressing module and a pneumatic load reducing module.The pile type platform structure for offshore photovoltaics integrates the pile body connecting module, the auxiliary connecting module, the dynamic vibration suppressing module and the pneumatic load reducing module into an integral whole through the integral wind vibration resisting connecting assembly, realizes the systematization and synergization of the wind vibration resisting function, greatly reduces the alternating stress amplitude that the structure bears for a long time by effectively suppressing vortex-induced vibration and reducing wind load, comprehensively solves the wind vibration and high wind pressure problems that offshore platforms face, and significantly improves the stability and fatigue resistance of the structure.

Description

Technical Field

[0001] This invention relates to the field of precast concrete pile processing technology, and in particular to a pile platform structure for offshore photovoltaic applications. Background Technology

[0002] With the development of the photovoltaic industry, offshore photovoltaic (PV) systems have gained attention due to their advantages such as not occupying land resources and having good cooling effects. Offshore PV platforms typically use pile foundation structures to support PV modules. However, the marine environment is complex and changeable, and the platform is constantly subjected to dynamic loads such as wind, waves, and currents. Among these, vortex-induced vibration and high wind pressure are the main causes of structural fatigue damage and failure.

[0003] In the wind, a slender steel pipe pile acts like a cantilever beam with its top being a free end. When the alternating force generated by vortex shedding acts on the pile, the pile top sways. Traditional pile-platform connection structures (such as simple single-layer clamps or direct welding) cause abrupt changes in stiffness at the connection point between the steel pipe pile and the platform support. This node often becomes the weakest point in the rigidity of the entire structural system. This weak connection point not only fails to effectively constrain the displacement of the pile top, but also becomes a "hinged point" or "elastic support" due to insufficient stiffness, lowering the natural frequency of the entire structure. This makes it more susceptible to being excited by vortex shedding frequencies generated within the common wind speed range, entering a resonance state. At the same time, it amplifies the vibration amplitude transmitted from the pile to the platform. In addition, the main beam acts like a huge "windbreak," directly guiding high-speed airflow to the pile behind it. This results in the windward side of the pile actually bearing much higher wind speeds and pressures than when it is an isolated single pile. This "shading effect" or "interference effect" makes the total wind load acting on the connection area much greater than the simple sum of the independent wind loads of each component, which can easily lead to loosening of connection nodes, cracking of welds, overall structural instability, or even destruction. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a pile platform structure for offshore photovoltaics to solve the problems mentioned in the background art.

[0005] The objective of this invention is achieved as follows: a pile-type platform structure for offshore photovoltaic systems, comprising steel pipe piles driven into the seabed and a platform support for supporting photovoltaic modules, the platform support comprising mutually perpendicular main beams and purlins, the platform support being fixedly connected to the upper part of the steel pipe piles via an integrated wind-vibration resistant connection assembly, the wind-vibration resistant connection assembly comprising:

[0006] The pile body connection module is sleeved on the outer wall of the steel pipe pile and includes an upper pile clamping component and a lower pile clamping component arranged at intervals. The upper pile clamping component and the lower pile clamping component are rigidly connected by a vertically arranged first connecting beam to form a rigid frame. Shear-resistant components are provided between the upper pile clamping component and the steel pipe pile.

[0007] The auxiliary connection module includes a diagonal brace and a second connecting beam. The diagonal brace connects the main beam and the upper pile clamp, and the second connecting beam connects the upper end of the steel pipe pile and the middle part of the main beam.

[0008] A dynamic vibration suppression module is respectively installed on the first connecting beam and the second connecting beam, and is used to suppress the vortex-induced vibration of the pile platform structure.

[0009] The pneumatic unloading module is installed at the bottom of the main beam and is used to guide the airflow to pass smoothly.

[0010] Preferably, both the upper and lower pile clamps are composed of two semi-circular clamps joined together, and each clamp has a flange edge with threaded holes on both sides.

[0011] Preferably, the shear-resistant component includes a washer fixed to the inner wall of the clamp and a fastening screw threaded onto the clamp, one end of which abuts against the steel pipe pile.

[0012] Preferably, the dynamic vibration damping module on the second connecting beam includes two parallel mounting plates, which are fixedly connected to the second connecting beam. A damper is fixedly connected between adjacent mounting plates. A first mass block is fixedly connected to one of the mounting plates, and a tuning spring is fixedly connected between the first mass block and the other mounting plate.

[0013] Preferably, the dynamic vibration damping module on the first connecting beam includes a tuning groove formed on the first connecting beam, a pendulum rod is hinged in the tuning groove, and a second mass block is fixedly connected to the free end of the pendulum rod.

[0014] Preferably, the pneumatic load reduction module includes a guide plate fixed to the bottom of one end of the main beam, the guide plate having an arc-shaped guide surface.

[0015] Preferably, the free end of the guide plate has a diverter plate, which is used to divert the airflow on the guide plate to both sides of the steel pipe pile. A diverter groove is provided in the middle of the diverter plate, and symmetrical baffles are provided on the diverter plate, which are respectively located on both sides of the diverter groove.

[0016] Preferably, the baffle is a hollow structure, the inner wall of the baffle is covered with a high-damping wear-resistant coating, and the inner cavity of the baffle is filled with several damping metal balls.

[0017] Preferably, the diagonal brace is connected to the upper pile member, the diagonal brace to the main beam, and the second connecting beam to the main beam through friction damping nodes.

[0018] Preferably, the friction damping node includes a first connecting plate fixed to the auxiliary connecting module, the first connecting plate having a sliding hole, a second connecting plate fixedly connected to both the main beam and the upper pile clamp, the second connecting plate having a fixing hole, a friction plate sandwiched between the first connecting plate and the second connecting plate, a fastening bolt passing through adjacent friction plates, one end of the fastening bolt passing through the sliding hole, the other end of the fastening bolt passing through the fixing hole, and a symmetrical disc spring assembly sleeved on the fastening bolt, the disc spring assembly being used to apply a constant preload to the friction pair composed of the first connecting plate, the friction plate and the second connecting plate.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1. By setting up an integrated wind-vibration-resistant connection assembly, the pile connection module, auxiliary connection module, dynamic vibration suppression module, and aerodynamic load reduction module are integrated into a whole, realizing the systematization and synergy of wind-vibration-resistant functions. Among them, the rigid frame composed of the upper pile clamping component, the lower pile clamping component, the first connecting beam, and the second connecting beam greatly enhances the overall stiffness of the connection node. The dynamic vibration suppression module directly acts on the first and second connecting beams on the vibration transmission path, which can effectively suppress the vortex-induced vibration of the steel pipe pile. The aerodynamic load reduction module optimizes the aerodynamic shape and reduces the wind load from the source. The diagonal bracing provides additional stability. This integrated design with multiple mechanisms effectively suppresses vortex-induced vibration and reduces wind load, greatly reducing the amplitude of alternating stress that the structure bears over a long period of time. It comprehensively solves the problems of wind vibration and high wind pressure faced by offshore platforms, and significantly improves the stability and fatigue resistance of the structure.

[0021] 2. The diversion plate at the end of the guide plate, along with its diversion groove and baffle, can actively and symmetrically divert the gathered airflow to both sides of the steel pipe pile, effectively preventing the airflow from re-converging behind the pile and generating large-scale vortices, thus further optimizing the vortex reduction effect. In addition, the hollow structure of the baffle is filled with damping metal balls and covered with a high-damping wear-resistant coating. When the baffle itself vibrates slightly in the wind, the damping metal balls will collide and rub against each other and against the inner wall of the baffle, thereby dissipating additional vibration energy and providing additional damping effect for the structure.

[0022] 3. When the wind vibration load is small, the first connecting plate and the second connecting plate are locked by static friction, and the whole is a rigid connection. When the wind vibration load exceeds the static friction threshold, the first connecting plate will slide slightly relative to the second connecting plate. The sliding range is limited by the length of the sliding hole. During this sliding process, the kinetic energy is converted into heat energy and dissipated through the sliding friction of the friction plate. The disc spring assembly ensures that the clamping force will not be significantly lost after multiple sliding, and the performance is stable. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0024] Figure 1 This is a three-dimensional structural diagram of a pile-type platform structure for offshore photovoltaic use in one embodiment.

[0025] Figure 2 This is a schematic diagram of the pile connection module structure in one embodiment.

[0026] Figure 3 This is a schematic diagram of the platform support and auxiliary connection module structure in one embodiment.

[0027] Figure 4 This is a schematic diagram of the dynamic vibration damping module structure on the second connecting beam in one embodiment.

[0028] Figure 5 This is a schematic diagram of the dynamic vibration damping module structure in one embodiment.

[0029] Figure 6 This is a schematic diagram of the dynamic vibration damping module structure on the first connecting beam in one embodiment.

[0030] Figure 7 This is a front view structural diagram of a pile platform structure for offshore photovoltaic use in one embodiment.

[0031] Figure 8 This is a side view of a pile platform structure for offshore photovoltaics in one embodiment.

[0032] Figure 9 This is a schematic diagram of the pneumatic load reduction module structure in one embodiment.

[0033] Figure 10 This is a cross-sectional view of the pneumatic load reduction module in one embodiment.

[0034] Figure 11This is a schematic diagram of a friction damping node structure in one embodiment.

[0035] Figure 12 This is a schematic diagram of the explosion structure of the friction damping node in one embodiment.

[0036] Figure label:

[0037] 100. Steel pipe pile; 200. Platform support; 210. Main beam; 220. Purlin; 300. Wind vibration resistant connection assembly; 310. Pile body connection module; 311. Upper pile clamp; 312. Lower pile clamp; 313. First connecting beam; 314. Shear member; 315. Clamp; 316. Flange edge; 317. Gasket; 318. Fastening screw; 320. Auxiliary connection module; 321. Diagonal brace; 322. Second connecting beam; 330. Dynamic vibration damping module; 331. Mounting plate; 332. Damping element. 333, First mass block; 334, Tuning spring; 335, Tuning groove; 336, Swing rod; 337, Second mass block; 340, Pneumatic load reduction module; 341, Guide plate; 342, Flow divider; 343, Flow divider groove; 344, Baffle; 345, Damping metal ball; 350, Friction damping node; 351, First connecting plate; 352, Sliding hole; 353, Second connecting plate; 354, Fixing hole; 355, Friction plate; 356, Fastening bolt; 357, Disc spring assembly. Detailed Implementation

[0038] 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.

[0039] like Figures 1-12 As shown, a pile-type platform structure for offshore photovoltaics includes steel pipe piles 100 driven into the seabed and a platform support 200 for supporting photovoltaic modules. The platform support 200 includes mutually perpendicular main beams 210 and purlins 220. The platform support 200 is fixedly connected to the upper part of the steel pipe piles 100 through an integrated wind-vibration-resistant connection assembly 300. The wind-vibration-resistant connection assembly 300 includes a pile body connection module 310, an auxiliary connection module 320, a dynamic vibration damping module 330, a pneumatic load reduction module 340, and diagonal bracing 321. The wind-vibration-resistant connection assembly 300 can be prefabricated on shore and assembled with the steel pipe piles 100 on site using clamps, making installation convenient. The parameters of the dynamic vibration damping module 330 can be tuned according to the environmental conditions of the specific sea area, making it highly adaptable.

[0040] First, steel pipe piles 100 are driven into the seabed of the designated sea area. Then, the prefabricated wind-vibration resistant connection assembly 300 is hoisted to the designed elevation position above the steel pipe piles 100. This assembly is fixed to the pile body via the pile body connection module 310 and auxiliary connection module 320. Next, the assembled platform support 200, including the main beam 210 and purlins 220, is connected to the pneumatic load-reducing module 340 on the wind-vibration resistant connection assembly 300. Finally, photovoltaic modules are installed on the purlins 220.

[0041] Please refer to Figure 2 The pile body connection module 310 is sleeved on the outer wall of the steel pipe pile 100, and the pile body connection module 310 includes an upper pile clamping member 311 and a lower pile clamping member 312 arranged at intervals. The upper pile clamping member 311 and the lower pile clamping member 312, and the upper end of the steel pipe pile 100 and the middle part of the main beam 210 are respectively rigidly connected by a vertically arranged first connecting beam 313 to form a rigid frame. Both the upper pile clamping member 311 and the lower pile clamping member 312 are provided with shear-resistant members 314 between themselves and the steel pipe pile 100.

[0042] It should be noted that the outer wall of the first connecting beam 313 is a smooth curved surface.

[0043] The rigid frame design of the pile connection module 310 and the shear-resistant component 314 ensure that the connection point has extremely high stiffness and anti-slip capability, and the force flow transmission path is clear and reliable.

[0044] Specifically, both the upper pile clamp 311 and the lower pile clamp 312 are composed of two semi-circular clamps 315 joined together, and each clamp 315 has a flange edge 316 with threaded holes on both sides.

[0045] It should be noted that the clamp 315 is a high-strength steel casting or a thick-walled forging. The adjacent semi-circular clamps 315 are connected by a high-strength bolt passing through the threaded hole on the flange edge 316, and the other end is preloaded with a nut.

[0046] The design uses two semi-circular clamps 315 connected by flanges 316 to facilitate installation and disassembly, making on-site construction and subsequent maintenance and adjustment easier, while ensuring a tight connection with the pile body.

[0047] Please refer to Figure 2 The shear-resistant component 314 includes a gasket 317 fixed to the inner wall of the clamp 315 and a fastening screw 318 threaded onto the clamp 315, with one end of the fastening screw 318 abutting against the steel pipe pile 100.

[0048] It should be noted that the gasket 317 is a surface-treated copper-based or zinc-based alloy gasket 317, or a sandblasted hardened steel gasket 317, which significantly improves the coefficient of friction.

[0049] After tightening the high-strength bolts of clamp 315, use a wrench to tighten each fastening screw 318 so that its end is firmly pressed against the pipe wall of steel pipe pile 100. The gasket 317 increases the coefficient of friction, while the fastening screw 318 generates huge normal pressure, thereby providing strong shear resistance through friction and preventing relative slippage between clamp 315 and steel pipe pile 100.

[0050] Please refer to Figure 3 The auxiliary connection module 320 includes a diagonal brace 321 and a second connecting beam 322. The diagonal brace 321 connects the main beam 210 and the upper pile clamp 311, and the second connecting beam 322 connects the upper end of the steel pipe pile 100 and the middle part of the main beam 210.

[0051] By setting up an integrated wind-vibration-resistant connection assembly 300, the pile connection module 310, auxiliary connection module 320, dynamic vibration suppression module 330, and aerodynamic load reduction module 340 are integrated into a whole, realizing the systematization and synergy of wind-vibration-resistant functions. Among them, the rigid frame composed of the upper pile clamping member 311, the lower pile clamping member 312, the first connecting beam 313, and the second connecting beam 322 greatly enhances the overall stiffness of the connection node. The dynamic vibration suppression module 330 directly acts on the first connecting beam 313 and the second connecting beam 322 on the vibration transmission path, which can effectively suppress the vortex-induced vibration of the steel pipe pile 100. The aerodynamic load reduction module 340 is optimized in terms of aerodynamic shape, reducing wind load from the source. The diagonal brace 321 provides crucial lateral support, which, together with the rigid frame, ensures the overall stability of the node. This integrated design of aerodynamic load reduction, structural reinforcement, and dynamic vibration suppression comprehensively solves the problems of wind vibration and high wind pressure faced by offshore platforms, and significantly improves the stability and fatigue resistance of the structure.

[0052] Please refer to Figure 4 , Figure 5 and Figure 6 The dynamic vibration suppression module 330 is respectively installed on the first connecting beam 313 and the second connecting beam 322, and the dynamic vibration suppression module 330 is used to suppress the vortex-induced vibration of the pile platform structure.

[0053] It should be further explained that the natural frequency of the dynamic vibration suppression module 330 on the first connecting beam 313 is tuned to be close to the first-order bending vibration frequency of the steel pipe pile 100 as a cantilever beam, mainly used to suppress the vortex-induced vibration of the pile body; the natural frequency of the dynamic vibration suppression module 330 on the second connecting beam 322 is tuned to be close to the first-order bending vibration frequency of the main beam 210 or the torsional vibration frequency of the overall structure, mainly used to suppress the fluttering and torsional vibration of the platform support 200. Through this precise tuning for different vibration modes, the two dynamic vibration suppression modules 330 are each responsible for suppressing different main vibration modes, without interfering with each other, working together to achieve efficient suppression of the broadband vibration of the complex offshore photovoltaic platform, achieving technical results superior to using a single vibration suppression module.

[0054] Because the vibration frequency of the main beam 210 is relatively high, please refer to... Figure 4 and Figure 5 The dynamic vibration damping module 330 on the second connecting beam 322 includes two parallel mounting plates 331. The mounting plates 331 are fixedly connected to the second connecting beam 322. A damper 332 is fixedly connected between adjacent mounting plates 331. A first mass block 333 is fixedly connected to one of the mounting plates 331. A tuning spring 334 is fixedly connected between the first mass block 333 and the other mounting plate 331.

[0055] A tuned mass system is formed by the first mass block 333 and the tuning spring 334. Its frequency can be precisely tuned by changing the mass and stiffness, with a wide tuning range, which facilitates precise matching of the vibration characteristics of the main beam 210. When the vibration is transmitted through the second connecting beam 322, the inertial force of the first mass block 333 is opposite to the structural vibration, and the energy is dissipated through the damper 332, thereby achieving efficient suppression of vortex-induced vibration at a specific frequency.

[0056] Because the vibration frequency of steel pipe pile 100 is low, please refer to... Figure 6 The dynamic vibration damping module 330 on the first connecting beam 313 includes a tuning groove 335 opened on the first connecting beam 313. A swing rod 336 is connected in the tuning groove 335 by a ball joint or a cross-axis universal joint. A second mass block 337 is fixedly connected to the free end of the swing rod 336. By adjusting the length of the swing rod 336, the low-order natural frequency of the steel pipe pile 100 can be accurately matched. The swing rod 336 and the second mass block 337 are embedded in the tuning groove 335, which requires little surrounding space and is very suitable for installation in the relatively restricted area of ​​the steel pipe pile 100.

[0057] Please refer to Figure 7 and Figure 8 The pneumatic load reduction module 340 is installed at the bottom of the main beam 210 and is used to guide the airflow to pass smoothly.

[0058] For details, please refer to Figure 9 The pneumatic load reduction module 340 includes a guide plate 341 fixed to the bottom of one end of the main beam 210. The guide plate 341 has an arc-shaped guide surface that bends toward the steel pipe pile 100.

[0059] The guide plate 341 fixed at the bottom of the main beam 210, with its arc-shaped guide surface, can smoothly guide the turbulent airflow that would otherwise impact the steel pipe pile 100 and the connection node, reducing the generation of vortices, thereby reducing wind load and vibration excitation from the aerodynamic source.

[0060] Please refer to Figure 9 The free end of the guide plate 341 has a diverter plate 342, which is used to divert the airflow on the guide plate 341 to both sides of the steel pipe pile 100. A diverter groove 343 is provided in the middle of the diverter plate 342, and symmetrical baffles 344 are provided on the diverter plate 342. The baffles 344 are located on both sides of the diverter groove 343.

[0061] The diversion plate 342 at the end of the guide plate 341, along with the diversion groove 343 and baffle 344 thereon, can actively and symmetrically divert the gathered airflow to both sides of the steel pipe pile 100, effectively preventing the airflow from re-converging behind the pile and generating large-scale vortices, thus further optimizing the vortex reduction effect.

[0062] Please refer to Figure 10 The baffle 344 adopts a hollow shell structure, and its inner wall is sprayed with a high-damping wear-resistant coating (such as a polymer coating containing ceramic particles). In the inner cavity, dozens of damping metal balls 345 of different diameters (such as copper balls or steel balls) are filled.

[0063] The hollow baffle 344 is filled with damping metal balls 345 and covered with a high-damping wear-resistant coating. When the baffle 344 vibrates slightly in the wind, the damping metal balls 345 collide and rub against each other and between the damping metal balls 345 and the inner wall of the baffle 344, thereby dissipating additional vibration energy and providing additional damping effect for the structure.

[0064] Please refer to Figure 7 The diagonal brace 321 is connected to the upper pile member 311, the diagonal brace 321 is connected to the main beam 210, and the second connecting beam 322 is connected to the main beam 210 through friction damping nodes 350.

[0065] The connection of friction damping nodes 350 not only provides support, but also becomes an energy-dissipating element. When the wind load is too large, controllable sliding friction can occur at the node, dissipating a large amount of energy, just like a structural fuse, protecting the main structure from damage.

[0066] Please refer to Figure 11 and Figure 12The friction damping node 350 includes a first connecting plate 351 fixed on the auxiliary connecting module 320. The first connecting plate 351 has a sliding hole 352. A second connecting plate 353 is fixedly connected to the main beam 210 and the upper pile clamp 311. The second connecting plate 353 has a fixing hole 354. A friction plate 355 is sandwiched between the first connecting plate 351 and the second connecting plate 353. A fastening bolt 356 passes through the adjacent friction plates 355. One end of the fastening bolt 356 passes through the sliding hole 352, and the other end of the fastening bolt 356 passes through the fixing hole 354. A symmetrical disc spring assembly 357 is sleeved on the fastening bolt 356. The disc spring assembly 357 is used to apply a constant preload to the friction pair composed of the first connecting plate 351, the friction plate 355 and the second connecting plate 353.

[0067] It should be noted that the sliding hole 352 is an oblong or elliptical hole, the fixing hole 354 is a round hole, and the friction plate 355 is made of a material with a high coefficient of friction, such as copper-based or zinc-based alloys, or steel sheets coated with wear-resistant ceramic coatings.

[0068] The specific working principle of the friction damping node 350 is as follows: When the wind vibration load is small, the first connecting plate 351 and the second connecting plate 353 are locked by static friction, and the whole is rigidly connected; when the wind vibration load exceeds the static friction threshold, the first connecting plate 351 will slide slightly relative to the second connecting plate 353. The sliding range is limited by the length of the sliding hole 352. During this sliding process, the kinetic energy is converted into heat energy and dissipated through the sliding friction of the friction plate 355. The disc spring assembly 357 ensures that the clamping force will not be significantly lost after multiple sliding, and the performance is stable.

[0069] The sliding hole 352 provides space for sliding, and the disc spring assembly 357 provides a stable and anti-relaxation preload for the friction pair formed by the friction plate 355, ensuring the long-term stability and reliability of the friction damping performance, and making the energy dissipation effect controllable and durable.

[0070] The working principle of this pile-type platform structure for offshore photovoltaics is a multi-level, collaborative defense system. Its core lies in the different modules in the integrated wind-vibration-resistant connection assembly 300, which systematically address offshore wind loads and vortex-induced vibrations from three levels: prevention, treatment, and protection. The specific working principle is as follows:

[0071] Level 1: Aerodynamic optimization, prevention at the source

[0072] Objective: To optimize the flow field and reduce the excitation force of wind load and vortex-induced vibration at the source.

[0073] Execution module: Pneumatic unloading module 340.

[0074] Airflow and pressure relief: When the airflow passes through the platform, it first encounters the pneumatic load reduction module 340 installed at the bottom of the main beam 210. The arc-shaped airflow guide surface of its guide plate 341 can smooth out the turbulent airflow that would normally directly impact the steel pipe pile 100 and the connecting node, making it smooth and delaying airflow separation, thereby reducing the vortex size and development behind the pile body.

[0075] Active diversion and energy dissipation: After being guided, the airflow reaches the diversion plate 342 at the end. The diversion groove 343 in the middle of the diversion plate 342 allows a portion of the airflow to pass through, which serves as a pressure relief function. The baffles 344 on both sides symmetrically guide the remaining airflow to both sides of the steel pipe pile 100. This design disrupts the periodicity of the Karman vortex street formation, making vortex shedding irregular and weakened. At the same time, the damping metal balls 345 inside the baffles 344 collide and rub against each other under wind-induced micro-vibrations, dissipating some energy.

[0076] This significantly reduces the intensity of aerodynamic loads and vortex-induced vibrations acting on the structure at the source.

[0077] Level 2: Dynamic vibration suppression, intermediate adjustment

[0078] Objective: To absorb and dissipate vibrational energy that cannot be completely eliminated, and to suppress resonance.

[0079] The execution module consists of a rigid frame for the dynamic vibration damping module 330, the pile connection module 310, and the auxiliary connection module 320.

[0080] Energy transfer and convergence: After the first stage of aerodynamic optimization, the residual vortex-induced vibration energy and the direct wind load will cause the steel pipe pile 100 to vibrate. This vibration is transmitted to the rigid frame composed of the first connecting beam 313 and the second connecting beam 322 through the pile body connecting module 310 and the auxiliary connecting module 320. This rigid frame not only enhances the structural stiffness, but more importantly, it converges the vibration energy into itself, providing an ideal platform for installing vibration damping devices.

[0081] Tuning and energy consumption:

[0082] When the first connecting beam 313 vibrates horizontally, the second mass block 337 at the end of the pendulum rod 336 will swing like a pendulum under inertia. Its swing frequency is related to the pendulum length. By tuning, its frequency is made to match the natural frequency of the structure. When the structure vibrates, the pendulum will generate a huge reverse inertial force, and the energy will be dissipated through frictional damping at the hinge.

[0083] When the second connecting beam 322 vibrates along with the structure, it will drive the mounting plate 331 on it to move. However, the first mass block 333 will tend to remain stationary due to inertia, thereby compressing or stretching the tuning spring 334. The inertial force of the first mass block 333 and the restoring force of the tuning spring 334 interact, causing the first mass block 333 to produce a movement opposite to the vibration direction of the second connecting beam 322. During this process, the damper 332 deforms, converting the vibration kinetic energy into heat energy and dissipating it.

[0084] Through precise tuning for different vibration modes, the two dynamic vibration suppression modules 330 are each responsible for suppressing different main vibration modes without interfering with each other. Working together, they achieve efficient suppression of broadband vibrations of complex offshore photovoltaic platforms, achieving technical results superior to using a single vibration suppression module. This effectively suppresses resonance phenomena and significantly reduces vibration amplitude.

[0085] Level 3: Frictional energy dissipation, final guarantee

[0086] Objective: To dissipate enormous energy through controlled sliding friction under extreme wind loads, serving as a safety precaution for the main structure.

[0087] Execution module: Friction damping node 350 at the end of the diagonal brace 321.

[0088] Elastic connection and critical slip: Under normal wind conditions, the friction damping node 350 remains locked under the huge preload provided by the disc spring assembly 357, and the diagonal brace 321 provides solid lateral support.

[0089] Passive energy dissipation and protection: When encountering extreme winds and the load exceeds the preset critical friction force, the friction damping node 350 activates. The first connecting plate 351 undergoes a slight slippage relative to the second connecting plate 353 along the sliding hole 352. The friction pair formed by the first connecting plate 351, friction plate 355, and second connecting plate 353 generates enormous frictional force during the slippage process, directly converting the kinetic energy of the destructive wind load into heat energy for dissipation. This process greatly consumes energy and prevents the enormous load from directly acting on the connection root of the main beam 210 and the steel pipe pile 100.

[0090] At critical moments, controlled sliding is used to protect the main structure and prevent it from undergoing irreversible plastic deformation or damage.

[0091] In summary, when wind blows across the platform, the airflow guides the airflow smoothly through the aerodynamic load reduction module 340, and the diverter plate 342 directs the airflow to both sides of the steel pipe pile 100, effectively disrupting the synchronicity of the vortex street and reducing the excitation force of vortex-induced vibration from the source. However, vibration cannot be completely avoided in a marine environment. At this time, the remaining vibration energy will be transmitted to the dynamic vibration suppression module 330 through the rigid frame. The tuned first mass block 333 and second mass block 337 will generate inertial forces opposite to the structural vibration, and the vibration energy will be consumed through the damper 332 or its own hinge friction. At the same time, if the wind load is too large and causes the structure to deform significantly, the friction damping node 350 at the end of the diagonal brace 321 will undergo controllable slippage, dissipating a large amount of energy through friction and protecting the safety of the main structure. The rigid frame of the pile connection module 310 ensures the integrity of the entire power transmission path. Each module has been professionally divided and systematically integrated for different stages and manifestations of wind vibration, resulting in a synergistic technical effect.

[0092] The specific application scenarios for the platform structure of a 20 MW offshore photovoltaic project in a certain sea area are as follows:

[0093] 1. Overall Layout and Main Parameters

[0094] Site conditions: The average water depth of the project area is 5 meters, the maximum wind speed during a 50-year return period is 42.5 m / s, and the pH value of the seawater is 8.2.

[0095] Photovoltaic array: Multiple pile platform structures as described in this invention are used as support units, each unit supporting a sub-array composed of 24 photovoltaic modules.

[0096] Steel pipe pile 100: Made of Q355C steel, 800mm in diameter, 16mm in wall thickness, driven into the seabed to a depth of about 20 meters depending on geological conditions.

[0097] Platform support 200: The main beam 210 and purlin 220 are both made of hot-dip galvanized H-beams and C-beams, with an overall size of approximately 12m x 4m.

[0098] 2. Prefabrication and installation of the wind-resistant vibration connection assembly 300

[0099] Installation of pile connection module 310:

[0100] First, the upper pile clamping component 311 and the lower pile clamping component 312 are welded into a rigid frame as a whole via the first connecting beam 313 at the onshore prefabrication plant. The distance between the upper pile clamping component 311 and the lower pile clamping component 312 is 1.8 meters.

[0101] Both the upper pile clamp 311 and the lower pile clamp 312 consist of two semi-circular clamps 315, made of Q355B steel. Each clamp 315 has flange edges 316 on both sides, and each flange edge 316 has two threaded holes drilled on it.

[0102] During offshore construction, the prefabricated rigid frame is hoisted to the design elevation of the top of the steel pipe pile 100 (approximately 6 meters above average sea level). The two halves of the clamp 315 are wrapped around the pile body, and high-strength bolts are passed through the threaded holes on the flange edge 316. The other end is pre-tightened with a nut.

[0103] Subsequently, the shear-resistant components 314 on each clamp 315 are tightened: First, a 65Mn steel 10mm thick washer 317 is welded to the inner wall of the clamp 315; then, the M20 fastening screws 318 are tightened with a torque wrench until their tips are firmly pressed against the wall of the steel pipe pile 100 with a torque of 120 N·m, forming a reliable anti-slip connection.

[0104] Installation of Dynamic Vibration Suppression Module 330:

[0105] The dynamic vibration damping module 330, as an independent unit, has been tuned at the prefabrication plant.

[0106] A pendulum rod 336 is installed on the first connecting beam 313. A second mass block 337 is fixedly connected to the free end of the pendulum rod 336. A plate 331 is fixedly installed on the second connecting beam 322. Both the first mass block 333 and the second mass block 337 are cast iron blocks. The tuning spring 334 is a custom-stiffened, high-fatigue-life helical spring. The damper 332 is a viscous fluid damper.

[0107] The natural frequency of the dynamic vibration suppression module 330 on the first connecting beam 313 is tuned to be close to the first-order bending vibration frequency of the steel pipe pile 100 as a cantilever beam, mainly used to suppress the vortex-induced vibration of the pile body. The natural frequency of the dynamic vibration suppression module 330 on the second connecting beam 322 is tuned to be close to the first-order bending vibration frequency of the main beam 210 or the torsional vibration frequency of the overall structure, mainly used to suppress the fluttering and torsional vibration of the platform support 200.

[0108] In this 20MW offshore photovoltaic project, finite element modal analysis determined the fundamental frequencies of the structure to be 1.8Hz (pile vibration) and 2.4Hz (main beam 210 vibration). Based on this, vibration suppression parameters were designed as follows: a first mass block 333, with a mass of 50kg, is mounted on the second connecting beam 322, and is paired with a tuned spring 334 with a stiffness of 28kN / m; a second mass block 337, with a mass of 60kg, is mounted on the first connecting beam 313, and is paired with a pendulum rod 336 with a pendulum length of 76mm. Calculations show that this configuration can achieve a vibration suppression efficiency of over 75% for the main vibration modes.

[0109] Installation of the pneumatic load reduction module 340 and the platform support 200:

[0110] The guide plate 341 and the flow divider 342 of the pneumatic load reduction module 340 are integrally molded from 5mm thick aluminum alloy plates and the surface is anodized. The radius of curvature of its guide surface has been optimized by computational fluid dynamics.

[0111] The pneumatic load reduction module 340 is fixedly installed at the bottom of one end of the main beam 210. Then, the assembled platform support 200 is hoisted into position, so that the end of the main beam 210 is fixedly connected to the top of the pneumatic load reduction module 340.

[0112] The baffle 344 is a hollow aluminum plate with a polyurethane-based high-damping wear-resistant coating sprayed on its inner wall. Its inner cavity is filled with copper damping metal balls 345 with a diameter of 10-15mm, and the filling volume accounts for about 60% of the inner cavity.

[0113] Installation of auxiliary connection module 320 and friction damping node 350:

[0114] The diagonal brace 321 is made of Φ159x6 round steel pipe, and both ends are connected by friction damping nodes 350. One end of the second connecting beam 322 is fixedly connected to the upper end of the steel pipe pile 100, and the other end of the second connecting beam 322 is connected by friction damping nodes 350.

[0115] At the prefabrication plant, a first connecting plate 351 is welded to both ends of the diagonal brace 321 and one end of the second connecting beam 322. The first connecting plate 351 has a 100x30mm sliding hole 352. The second connecting plate 353 is welded to the corresponding positions of the lower flange of the main beam 210 and the upper pile clamp 311. The plate has a Φ26mm fixing hole 354.

[0116] During on-site installation, a friction plate 355 (asbestos-free composite material) is placed between the first connecting plate 351 and the second connecting plate 353, and a 10.9 grade fastening bolt 356 is inserted. At both ends of the fastening bolt 356, a set of disc spring assemblies 357 (each set consisting of 8 mating disc springs) is installed on the outside of the friction plate 355. Then, the nuts are tightened to a predetermined torque using a hydraulic torque wrench to provide a constant and anti-loosening preload of 25kN for the friction pair.

[0117] Work process and results:

[0118] Normal operation (wind speed <20m / s): Under light to moderate wind conditions at sea, the aerodynamic load reduction module 340 effectively guides the airflow, resulting in a stable flow field around the platform and weak vortex-induced vibration. The dynamic vibration suppression module 330 is in standby mode, the friction damping node 350 is in locked mode, and the structure has good rigidity.

[0119] Under strong wind conditions (wind speed 20m / s ~ 35m / s): the airflow is enhanced, and the guiding and diversion effects of the aerodynamic load reduction module 340 are significant, but periodic vortex-induced forces are still generated. At this time, the steel pipe pile 100 experiences slight vibration, and the energy is transferred to the first connecting beam 313 and the second connecting beam 322. The dynamic vibration suppression module 330 is activated, and the first mass block 333 and the second mass block 337 move violently in opposite phases, and their energy is efficiently dissipated. Observations show that the platform amplitude is reduced by more than 60% compared with the traditional structure without this module.

[0120] Extreme wind conditions (wind speed > 35 m / s): Under rare strong winds, the load is enormous. When the force acting on the diagonal brace 321 or the second connecting beam 322 exceeds the preset friction force of the friction damping node 350, the node undergoes controlled slippage (approximately 5-15 mm). During the slippage, friction generates heat, dissipating a significant amount of wind energy. Like a structural fuse, this effectively protects key structural elements such as the main beam 210 and the base of the steel pipe piles 100 from plastic failure. After the wind load decreases, the node returns to its original position under the action of the disc spring assembly 357.

[0121] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A pile-type platform structure for offshore photovoltaic (PV) applications, comprising steel pipe piles (100) driven into the seabed and a platform support (200) for supporting PV modules, the platform support (200) comprising mutually perpendicular main beams (210) and purlins (220), characterized in that, The platform support (200) is fixedly connected to the upper part of the steel pipe pile (100) via an integrated wind-vibration-resistant connection assembly (300), the wind-vibration-resistant connection assembly (300) comprising: The pile body connection module (310) is sleeved on the outer wall of the steel pipe pile (100) and includes an upper pile clamping member (311) and a lower pile clamping member (312) arranged at intervals. The upper pile clamping member (311) and the lower pile clamping member (312) are rigidly connected to form a rigid frame through a vertically arranged first connecting beam (313). Both the upper pile clamping member (311) and the lower pile clamping member (312) are provided with shear-resistant members (314) between them and the steel pipe pile (100). The auxiliary connection module (320) includes a diagonal brace (321) and a second connecting beam (322). The diagonal brace (321) is connected between the main beam (210) and the upper pile clamp (311), and the second connecting beam (322) is connected between the upper end of the steel pipe pile (100) and the middle part of the main beam (210). The dynamic vibration suppression module (330) is respectively disposed on the first connecting beam (313) and the second connecting beam (322), and is used to suppress the vortex-induced vibration of the pile platform structure; A pneumatic load reduction module (340) is installed at the bottom of the main beam (210) and is used to guide the airflow to pass smoothly. The dynamic vibration damping module (330) on the second connecting beam (322) includes two parallel mounting plates (331). The mounting plates (331) are fixedly connected to the second connecting beam (322), and a damper (332) is fixedly connected between adjacent mounting plates (331). A first mass block (333) is fixedly connected to one of the mounting plates (331), and a tuning spring (334) is fixedly connected between the first mass block (333) and the other mounting plate (331). The dynamic vibration damping module (330) on the first connecting beam (313) includes a tuning groove (335) opened on the first connecting beam (313), a swing rod (336) is hinged in the tuning groove (335), and a second mass block (337) is fixedly connected to the free end of the swing rod (336). The pneumatic load reduction module (340) includes a guide plate (341) fixed to the bottom of one end of the main beam (210), the guide plate (341) having an arc-shaped guide surface; The diagonal brace (321) is connected to the upper pile member (311), the diagonal brace (321) is connected to the main beam (210), and the second connecting beam (322) is connected to the main beam (210) through friction damping nodes (350).

2. The pile platform structure for offshore photovoltaic power according to claim 1, characterized in that, The upper pile clamp (311) and the lower pile clamp (312) are both composed of two semi-circular clamps (315) joined together, and each clamp (315) has a flange edge (316) with threaded holes on both sides.

3. The pile platform structure for offshore photovoltaic power according to claim 2, characterized in that, The shear-resistant component (314) includes a gasket (317) fixed to the inner wall of the clamp (315) and a fastening screw (318) threaded onto the clamp (315), one end of which abuts against the steel pipe pile (100).

4. The pile platform structure for offshore photovoltaic power according to claim 3, characterized in that, The free end of the guide plate (341) has a diversion plate (342), which is used to divert the airflow on the guide plate (341) to both sides of the steel pipe pile (100). A diversion groove (343) is provided in the middle of the diversion plate (342), and symmetrical baffles (344) are provided on the diversion plate (342). The baffles (344) are located on both sides of the diversion groove (343).

5. The pile platform structure for offshore photovoltaic power according to claim 4, characterized in that, The baffle (344) is a hollow structure, the inner wall of the baffle (344) is covered with a high-damping wear-resistant coating, and the inner cavity of the baffle (344) is filled with several damping metal balls (345).

6. The pile platform structure for offshore photovoltaic power according to claim 5, characterized in that, The friction damping node (350) includes a first connecting plate (351) fixed to the auxiliary connecting module (320), the first connecting plate (351) having a sliding hole (352), a second connecting plate (353) fixedly connected to both the main beam (210) and the upper pile clamp (311), the second connecting plate (353) having a fixing hole (354), and a friction plate (355) sandwiched between the first connecting plate (351) and the second connecting plate (353). A fastening bolt (356) is provided between the adjacent friction plates (355). One end of the fastening bolt (356) passes through the sliding hole (352), and the other end of the fastening bolt (356) passes through the fixing hole (354). A symmetrical disc spring assembly (357) is sleeved on the fastening bolt (356). The disc spring assembly (357) is used to apply a constant preload to the friction pair composed of the first connecting plate (351), the friction plates (355), and the second connecting plate (353).

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