Wind wave flow-earthquake coupling load simulation device and method for offshore wind power system

Abstract

The invention discloses a wind wave flow-earthquake coupling load simulation device and method for an offshore wind power system, and relates to the technical field of offshore wind power. The device comprises a comprehensive simulation platform, a model installation area and a data acquisition and monitoring system, wherein the comprehensive simulation platform cooperatively simulates a wind wave flow and an earthquake coupling load through a rectangular water tank, a vibration table system, a wave maker system and a water flow driving device; the model installation area is provided with special installation structures matched with multiple types of foundations such as pile foundations and jacket foundations, and multiple types of sensors are arranged in a matched mode. And the data acquisition and monitoring system realizes data acquisition, analysis and image recognition. According to the method, system safety evaluation is completed through model preparation, coupling load application and data acquisition and analysis. The problems that an existing device is single in simulation and poor in adaptability are solved, and an accurate and reliable experiment means is provided for stability research of an offshore wind power system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of offshore wind power, in particular to a wind wave current-seismic coupling load simulation device and method for offshore wind power system. BACKGROUND

[0002] With the increasing demand for clean energy worldwide, offshore wind power has developed rapidly due to its abundant resources, non-land space occupation, and stable wind speed. China has a long coastline and abundant offshore wind energy resources, and the installed capacity of offshore wind power will continue to grow rapidly. Offshore wind power systems are composed of wind turbines, foundation structures, transmission lines, and other components, which need to withstand complex environmental loads during operation.

[0003] The complex loads faced by offshore wind power systems include wind wave current loads and seismic loads. Wind load is one of the main loads, with wind speed and direction changing over time, as well as extreme conditions such as strong winds and gusts. Wave load has randomness and complexity, with different wave periods, heights, and shapes producing horizontal forces, vertical forces, and overturning moments. Current load can produce a sustained force on the foundation structure, and is superimposed with wind and wave loads, increasing the complexity of structural stress. Some offshore wind farms are located in areas with frequent seismic activity, and seismic loads are sudden and high-intensity, posing a serious threat to system stability. In actual marine environments, these loads are coupled with each other, making the system stress situation extremely complex and potentially leading to unexpected damage patterns.

[0004] Currently, numerical simulation and experimental devices are commonly used to study the stability of offshore wind power systems under complex loads, but both have limitations. Numerical simulation relies on accurate mathematical models and parameter settings, but the actual marine environment is complex, and existing numerical methods cannot accurately reflect wave nonlinearity, breaking, fluid-structure coupling, and seismic wave propagation and attenuation, resulting in deviations between calculated results and actual conditions. Most existing experimental devices can only simulate single or partial loads and cannot fully simulate wind wave current-seismic coupling loads. A few devices that can simulate multiple loads have limited simulation accuracy and range, and poor applicability to different foundation types, making it difficult to meet the needs of stability research on offshore wind power systems with various foundation types. Therefore, it is of great practical significance and urgency to develop a new simulation device and method. SUMMARY

[0005] The purpose of the present application is to provide a wind wave current-seismic coupling load simulation device and method for offshore wind power systems, which solves the problem of existing devices simulating single loads and poor adaptability, and provides a precise and reliable experimental means for offshore wind power system stability research.

[0006] To achieve the above-mentioned purpose, the present application provides a wind wave current-seismic coupling load simulation device for offshore wind power systems, which comprises a comprehensive simulation platform, a model installation area, and a data acquisition and monitoring system. The integrated simulation platform includes a rectangular water tank, a shaking table system, a wave generator system, and a water flow drive device. The rectangular water tank is made of high-strength steel and has a vibration isolation device at the bottom. The shaking table system is installed at the center of the bottom of the rectangular water tank and has three-dimensional vibration capability to simulate sine waves, triangular waves, random waves, and seismic waves from actual earthquake records. The wave generator system is installed at one end of the rectangular water tank to generate regular waves, irregular waves, or isolated waves, and multiple wave generators are coordinated to achieve wave superposition in different directions and frequencies. The water flow drive device consists of multiple axial flow pumps, which are installed at the bottom and side walls of the rectangular water tank to control the water flow speed and direction. Water flow sensors are installed inside the rectangular water tank to monitor water flow parameters in real time. The model installation area is located in a rectangular water tank and is equipped with a special installation structure that adapts to pile foundation models, jacket foundation models, gravity foundation models, suction foundation models, or floating foundation models; resistance strain gauges and acceleration sensors are arranged at the bottom and top of the tower, the root and tip of the fan blades of the scaled-down model of the offshore wind power system. The data acquisition and monitoring system includes several high-speed cameras arranged around a rectangular water tank, a central control system, data acquisition cards and data analysis software installed in the central control system; the data acquisition cards are used to acquire sensor data; the data analysis software integrates data processing algorithms and analysis models for statistical analysis, spectrum analysis, time history analysis and image recognition analysis.

[0007] Preferably, the pile foundation model is a scaled-down model of an offshore wind power system using pile foundations. Resistance strain gauges are arranged at intervals along the length of the pile body, and an acceleration sensor is installed on the top of the pile. The special installation structure for the pile foundation in the model installation area includes several pile holes with adjustable depth and verticality, and the pile holes are filled with a clay-sand mixture material that simulates the interaction between the pile and the soil.

[0008] Preferably, the jacket foundation model is a scaled-down model of an offshore wind power system using a jacket foundation. The dedicated installation structure for the jacket foundation in the model installation area includes connection nodes and support structures that match the jacket foundation. The support structure is fixedly connected to the bottom of the rectangular water tank. The connection nodes are set on the support structure. The position and size of the bolt holes of the connection nodes are adapted to the jacket foundation. Resistance strain gauges are attached to the connection nodes. An acceleration sensor is installed on the top of the main column of the support structure.

[0009] Preferably, the gravity foundation model is a scaled-down model of an offshore wind power system using a gravity foundation; the gravity foundation-specific installation structure in the model installation area includes an installation platform calibrated for levelness, the installation platform is connected to the bottom of a rectangular water tank through pre-embedded anchors, pressure sensors are evenly arranged on the contact surface between the bottom of the gravity foundation and the installation platform, and an acceleration sensor is arranged at the center of the top of the gravity foundation.

[0010] Preferably, the suction foundation model is a scaled-down model of an offshore wind power system using a suction foundation. Resistance strain gauges and pressure sensors are arranged at intervals along the height direction on the side wall of the suction foundation, and an acceleration sensor is installed on the top. The special installation structure for the suction foundation in the model installation area includes a sealing component, a soil simulation container, and a vacuuming component. The soil simulation container is a cylindrical steel barrel with an open top. The inner wall of the steel barrel is marked with graduation lines. The inside of the steel barrel is filled with silty sand and compacted to a preset density. The bottom of the steel barrel is fixedly connected to a rectangular water tank. The sealing assembly consists of an annular rubber gasket and a metal pressure ring. The annular rubber gasket is embedded in the groove at the top edge of the soil simulation container. The metal pressure ring is connected to the top flange of the soil simulation container by bolts and presses the annular rubber gasket tightly. The upper surface of the annular rubber gasket is tightly fitted with the steel flange face at the bottom of the suction foundation to form a seal. The vacuum assembly includes a vacuum pump, a vacuum gauge, and a vacuum line. One end of the vacuum line is connected to the vacuum valve on the top of the suction foundation through a sealed interface, and the other end is connected to the vacuum pump. The vacuum gauge is connected in series on the vacuum line to monitor the internal vacuum level of the suction foundation.

[0011] Preferably, the floating foundation model is a scaled-down model of an offshore wind power system using a floating foundation, with an acceleration sensor installed at the center of the deck of the floating foundation; the special installation structure for the floating foundation in the model installation area includes multiple anchor points and adjustable mooring cables, and different mooring methods of the offshore wind power system model are simulated by adjusting the pretension and length of the adjustable mooring cables, with tension sensors arranged at the mooring connection points between the adjustable mooring cables and the floating foundation.

[0012] A simulation method for a wind-wave-current-seismic coupled load simulation device for offshore wind power systems, comprising the following steps: S1. Model Preparation: S1.1. Based on the criteria of geometric similarity, material similarity, mechanical similarity and environmental load similarity, construct pile foundation models, jacket foundation models, gravity foundation models, suction foundation models or floating foundation models. S1.2 Select the corresponding special installation structure according to the foundation type, and install the scaled-down model of the offshore wind power system in the model installation area; S1.3. Perform static loading and modal tests, and debug the model and sensors according to the test results to ensure that the connection of each component is reliable and the sensors are working properly. S2, Application of coupled load: S2.1 Start the water flow drive device, adjust the axial flow pump speed and flow rate to form a stable water flow field, and monitor the water flow parameters through the water flow sensor until they meet the test requirements; S2.2 After the water flow stabilizes, start the wave generator system, set the wave parameters, generate regular waves, irregular waves or isolated waves, monitor and fine-tune the wave parameters through wave sensors to form a stable coupling between waves and water flow; S2.3 After the waves and water flow are stably coupled, start the shaking table system, input the parameters of sine wave, triangular wave, random wave or actual earthquake record, simulate the earthquake action, and monitor the vibration parameters through the acceleration sensor set in the shaking table system. S3. Data Acquisition and Analysis: S3.1 During the application of coupled loads, the dynamic response process of the scaled model of the offshore wind power system is captured in real time by a high-speed camera, and the sensor detection data is collected by a data acquisition card. S3.2. Use data analysis software to filter, denoise, and perform zero drift correction preprocessing on the collected data, and then perform statistical analysis, spectrum analysis and time history analysis. Combine with image recognition analysis to obtain the deformation and motion trajectory of the scaled model of the offshore wind power system. S3.3. Based on the analysis results, assess the safety of the scaled model of the offshore wind power system under coupled loads, determine the structural damage, the extent to which deformation exceeds the allowable range, and whether the vibration is at an acceptable level, and feed this information back to the system design optimization.

[0013] Preferably, in S1.3, the static loading test process is as follows: a horizontal loading support and a vertical loading jack are temporarily fixed on a rectangular water tank. The horizontal loading support is connected to the top of the offshore wind power scale-up model via steel cables, and the vertical loading jack is connected to the top of the offshore wind power scale-up model via a pressure plate. Horizontal loads are applied to the offshore wind power scale-up model in stages through the horizontal loading support, and vertical loads are applied to the offshore wind power scale-up model in stages through the vertical loading jack. Displacement and stress data of the offshore wind power scale-up model under different load levels are collected. The collected load-displacement measured data are compared with the finite element calculation values ​​of the corresponding working conditions to verify the similarity between the mechanical response of the offshore wind power scale-up model and the actual offshore wind power system.

[0014] Preferably, in S1.3, the modal testing process is as follows: the central control system inputs a sweep frequency control signal to the vibration table system, controlling the vibration table system to continuously adjust the vibration frequency along a preset frequency range to form a sweep frequency vibration excitation; the vibration response data of the offshore wind power scaled-down model is collected by an accelerometer installed on the offshore wind power scaled-down model, and the response data is subjected to spectrum analysis using data analysis software to extract the natural frequencies and mode shapes of the offshore wind power scaled-down model, verifying the similarity between the dynamic characteristics of the offshore wind power scaled-down model and the actual offshore wind power system.

[0015] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: (1) Comprehensive and accurate simulation This invention achieves, for the first time, a comprehensive and accurate simulation of wind-wave-seismic coupled loads. Compared to existing technologies, it more realistically reflects the complex load conditions faced by offshore wind power systems in actual operating environments. By precisely controlling the shaking table, wave generator, and water flow drive device, the synergistic effects of seismic waves, waves, and water flow are realized, and the load parameters can be flexibly adjusted according to actual needs. This provides more realistic data for the stability study of offshore wind power systems, and helps to reveal the mechanical response mechanisms and failure modes of structures under complex coupled loads.

[0016] (2) High versatility This device is applicable to various types of offshore wind turbine foundations, overcoming the limitation of existing devices that only address specific needs. Whether it's common pile foundations, jacket foundations, gravity foundations, suction foundations, or floating foundations, stability studies can be conducted on this simulation device. This allows researchers to comprehensively compare the performance differences of different foundation types under coupled loads, providing a more comprehensive and scientific basis for the selection and optimization of offshore wind turbine foundations. It greatly improves the versatility and comprehensiveness of the research, contributing to the overall development of offshore wind power technology.

[0017] (3) The data is reliable and abundant. Equipped with high-precision sensors and high-speed cameras, along with an advanced data acquisition and analysis system, the device can acquire a large amount of accurate and comprehensive data. It can not only collect traditional mechanical parameters such as stress, strain, and displacement of the structure under coupled loads, but also record the dynamic response process of the structure through high-speed imaging technology, providing more intuitive and comprehensive information for research. In-depth analysis of this data can more accurately assess the stability of offshore wind power systems, providing reliable data support for engineering design and safety assessment, and helping to improve the construction quality and operational safety of offshore wind farms.

[0018] (4) Promote technological development The simulation device and method of this invention provide a novel experimental approach for studying the stability of offshore wind power systems, contributing to the further development of offshore wind power technology. By simulating various complex operating conditions in a laboratory environment, researchers can fully verify and optimize different schemes during the project design phase, reducing risks and uncertainties in actual engineering. This will accelerate the research and application of new offshore wind power technologies, promote the development of the offshore wind power industry towards higher efficiency and greater safety and reliability, and provide strong technical support for the sustainable development of my country's offshore wind power industry.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall structure of the integrated simulation platform of an embodiment of the wind-wave-current-seismic coupled load simulation device for offshore wind power systems according to the present invention.

[0022] Figure Labels 1. Rectangular water tank; 2. Vibration table; 3. Hydraulic servo chamber; 4. Hydraulic rod; 5. Axial flow pump; 6. Fan tower; 7. Fan blades; 8. Sensor; 9. Wave generator system; 10. Industrial fan array; 11. High-speed camera; 12. Specialized installation structure; 13. Water tank bottom; 14. Support frame; 15. Energy dissipation net. Detailed Implementation

[0023] 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1 (a) Preparation of the simulation device 1. Debugging of the integrated simulation platform (1) Water tank inspection and cleaning The interior of the rectangular water tank 1, made of high-strength steel, was thoroughly cleaned using a neutral detergent and a high-pressure water gun. A support frame 14 was installed below the bottom surface 13, and energy-dissipating nets 15 were installed on the side walls. An industrial fan array 10 was installed above the tank. During cleaning, special attention was paid to removing residual impurities, oil stains, and water stains from the bottom, side walls, and corners. The inner wall was wiped with a white cloth until no visible stains were visible, ensuring a smooth, bump-free surface. Water was added to the tank to 80% of the designed test depth and allowed to stand for 24 hours. Leaks were observed at the welds, flange connections, and seals. If leaks were found, the welds were repaired by welding, and aged seals were replaced with water-resistant rubber seals. Simultaneously, the vibration isolation device at the bottom of the tank was checked, ensuring that the connecting bolts were secure and the damper was free of oil leaks. The overall level of the tank was calibrated using a level, with the error controlled within ±2mm / m per meter.

[0026] (2) Vibration table system calibration A cylindrical standard mass block conforming to JJG 948-2019 standard is bolted to the center of the vibration table surface 2. The mass block's mass is known and its error does not exceed ±0.1%. The vibration table servo system consists of a hydraulic servo chamber 3 and several hydraulic rods 4, which are connected to the vibration table surface 2. A data acquisition card connecting the vibration table servo control system and the central control system is used. The vibration table outputs a sine wave signal, with the frequency adjusted in increments from 0.1Hz to 100Hz, each increment being 10Hz. The acceleration amplitude is gradually increased from 0.1g to 5g, with each increment being 0.5g. Each parameter setting is maintained for 1.5 minutes of stable operation, and the acceleration response data of the mass block is collected synchronously. The collected measured acceleration values ​​are compared with the control system's set values. If the error exceeds ±5%, it is corrected by adjusting the vibration table's gain parameters, servo valve opening, and other calibration procedures until the output error of all parameter settings is controlled within the allowable range. After calibration, the calibration parameters are saved to the central control system.

[0027] (3) Wave generator system 9 test Fill the water tank with clean water to the test depth, which is determined according to the model dimensions. Start the wave generator system 9, which is a push-plate structure installed at one end of the water tank. First, conduct a regular wave test, setting the wave height to 0.2m and the period to 2s. The wave generator runs continuously for 8 minutes, collecting wave height and period data in real time through wave sensors such as capacitive wave height meters placed in the middle of the water tank and near the model installation area, recording the average value every 30 seconds. If the measured wave height deviates from the set value by more than ±3%, or the period deviates by more than ±0.1 seconds, fine-tune the movement stroke, frequency, and phase of the wave generator push plate until the parameters meet the standards. Then switch to the irregular wave test, setting the wave parameters according to the JONSWAP spectrum: effective wave height 0.3m, peak period 3s, peak factor 3.3. The wave generator runs continuously for 20 minutes. The wave field distribution in different areas (front, middle, and model area) of the water tank is monitored by multiple wave sensors. If there are areas where the wave non-uniformity coefficient (maximum wave height / minimum wave height) exceeds 1.2, the push plate spacing of the wave generator and the timing of the coordinated control are adjusted to ensure that the wave field is uniform and stable.

[0028] (4) Trial operation of the water flow drive system The water flow drive device, consisting of multiple axial flow pumps 5 installed at the bottom and side walls of the water tank, is activated. The rotational speed of the axial flow pumps 5 is adjusted using a low-speed incremental method, setting the target water flow velocity to 0.5 m / s and the flow direction to 0° (along the length of the water tank). Six monitoring points are set up: one electromagnetic flowmeter every 2 m along the length and one every 1.5 m along the width. After the water flow stabilizes for 10 minutes, the flow velocity and flow direction data at each monitoring point are collected synchronously. If the flow velocity deviation at any monitoring point exceeds ±0.1 m / s, or the flow direction deviation exceeds ±5°, the rotational speed of the corresponding axial flow pump 5 is adjusted (bottom pumps control longitudinal flow velocity, side wall pumps control lateral flow velocity), and guide vanes are added to optimize the water flow direction until the water flow parameters at all monitoring points meet the set requirements. During the trial operation, the stability of data transmission between the water flow sensors and the central control system is checked to ensure real-time monitoring without delay.

[0029] 2. Layout of the wind power system model installation area (1) Preparation of multi-type special installation structure 12 Pile foundation interface: A laser positioning instrument is used to calibrate the center position and verticality of the pile hole. The deviation between the center of the pile hole and the central axis of the water trough should not exceed ±2mm, and the verticality error should not exceed ±0.5 degrees. The number of pile holes matches the number of test models, usually 1-3. The pile hole is filled with a clay-sand mixture with a clay-sand mass ratio of 3:7. It is compacted in layers, with each layer being 100mm thick and the compaction degree not less than 90%, thus simulating the actual pile-soil interaction. A hydraulic positioning clamp is installed at the top of the pile hole to adjust the installation depth (adjustable from 1-3m) and verticality of the pile foundation model.

[0030] The jacket foundation interface: Check the levelness of the support structure. The support structure is fixed to the bottom of the water tank with pre-embedded bolts, and the levelness error should not exceed ±1mm / m. Ensure that the position and size of the bolt holes at the connection nodes are precisely matched with the flanges of the jacket model, with a hole diameter tolerance not exceeding ±0.1mm and a hole position deviation not exceeding ±0.5mm. Weld the connection nodes to the top of the support structure. After welding, perform non-destructive testing such as penetrant testing to ensure there are no welding defects. The design torque is 100-150N. m) Pre-tighten the connecting bolts and mark them to prevent loosening.

[0031] Gravity-based foundation interface: The installation platform is leveled using a precision level, with a levelness error not exceeding ±1mm per meter. The platform is connected to the bottom of the water tank via pre-embedded anchors. The anchors are made of stainless steel with a tensile strength of not less than 400MPa, and the anchor spacing is determined according to the center of gravity distribution of the gravity-based foundation model. Foundation installation positioning lines are marked on the platform surface to ensure that the center of gravity of the model is aligned with the platform center after installation.

[0032] Suction-type base interface: Inspect the sealing assembly, which consists of an annular rubber gasket and a metal pressure ring, ensuring the rubber gasket is undamaged and has good elasticity. Embed the annular rubber gasket into the annular groove on the top edge of the soil simulation container (a cylindrical steel drum with an open top). Connect the metal pressure ring to the top flange of the container with bolts. After pre-tightening, check the compression of the rubber gasket, ensuring it is 20%–30% of its thickness. Fill the container with silty sand, the particle size distribution of which matches the actual seabed soil layer. Compact it in layers to the preset density, and test it using the ring cutter method; the density deviation should not exceed ±0.05 g / cm³. 3 Connect the vacuum assembly (including vacuum pump, vacuum gauge, and evacuation lines) and perform a sealing test. Evacuate to -0.08 MPa and maintain for five minutes. The vacuum level should not drop by more than 0.005 MPa.

[0033] Floating foundation interface: Four anchor points are arranged in a square pattern at the bottom of the tank. The anchor points are made of Q235 steel, buried at a depth of not less than 300mm, and the spacing between the anchor points matches the mooring radius of the floating foundation model. Install adjustable mooring cables. The cables are made of nylon with a breaking strength of not less than 5kN. One end of the cable is fixed to the anchor point, and the other end is reserved for connection to the floating foundation mooring point. Adjust the cable pretension (using a tension adjuster) to the design range to ensure that the cable is neither slack nor overstretched.

[0034] (2) Installation and debugging of sensor 8 Install sensor 8 as follows: Pile foundation model: Resistance strain gauges (model BX120-3AA) are pasted at 150mm intervals along the length of the pile. Before pasting, the surface of the pile is ground to a roughness Ra of no more than 1.6μm and coated with a moisture-proof agent. An accelerometer (model CA-YD-187, range ±50g) is fixed to the top of the pile with M16 bolts. The sensor cable is tied and fixed along the pile and led to the junction box outside the water tank.

[0035] Basic model of the jacket structure: Resistance strain gauges are glued to the surface of each connection node, with four gauges glued to each node and evenly distributed along the circumference. Accelerometers are fixed to the top of the main columns of the supporting structure using strong adhesives such as water-resistant epoxy resin. The sensor cables are threaded through pre-drilled holes inside the columns to avoid direct contact with water flow and waves.

[0036] Gravity-based foundation model: Six pressure sensors (model CYG1101, range 0-1MPa) are arranged equidistantly along the circumference on the contact surface between the bottom of the foundation and the mounting platform. The tops of the sensors are tightly fitted to the bottom of the foundation. An accelerometer is fixed to the center of the top of the foundation by a metal bracket, the bracket being 100 mm higher than the top surface of the foundation to avoid obstructing the sensor.

[0037] Suction-type foundation model: A set of sensors is arranged at 100 mm intervals along the height of the sidewall. Each set contains four resistance strain gauges and two pressure sensors, evenly distributed along the circumference. An acceleration sensor is fixed to the center of the top of the foundation with bolts, and the pressure sensor probe is flush with the sidewall of the foundation to ensure accurate monitoring of soil pressure or water pressure data.

[0038] Floating foundation model: Tension sensors (model JLBM-5, range 0-10kN) are installed at the mooring connection points of each mooring cable and the foundation, and the sensors are connected in series with the cables. An acceleration sensor is fixed to the center of the foundation deck via a waterproof bracket. The sensor has an IP67 protection rating to ensure normal operation in the water surface environment.

[0039] After all sensors 8 are installed, connect them to the data acquisition card of the central control system and perform a power-on test. Apply a standard signal to the sensors 8 (e.g., apply a known strain to the strain gauge or a known acceleration to the accelerometer), and check that the deviation between the signal value received by the data acquisition card and the standard value does not exceed ±1%, ensuring that the sensors 8 are working properly. At the same time, check the waterproof seal at the cable connections, using waterproof tape and sealing boxes to prevent water from entering and damaging the sensors 8 during the test.

[0040] 3. Data Acquisition and Monitoring System Setup (1) Setup and debugging of high-speed camera 11 Four high-speed cameras 11 (model MER-2000-19U3M) are arranged around a rectangular water tank 1, mounted above the four corners of the tank at a height of 2-3m. The shooting angle is adjusted using a universal bracket. The camera's field of view is ensured to cover the entire height of the base model, the connection between the tower and the blades, the entire movement trajectory of the blades, and the area affected by waves and water flow within the tank. Camera parameters are set as follows: resolution 1920×1080 pixels, frame rate 200 frames per second (adjustable to 500 frames per second according to experimental requirements), exposure time 1 / 1000 second, to avoid motion blur. Each camera is calibrated using a standard calibration plate with an accuracy of 0.01 mm to obtain intrinsic parameters (focal length, principal point coordinates) and extrinsic parameters (position, attitude). Time synchronization of the four cameras is achieved through a central control system, with a synchronization error not exceeding ±1ms.

[0041] (2) Configuration of sensor 8 data acquisition system In the data analysis software of the central control system, a database corresponding to the sensors and their foundation components is established. Each sensor (8) is numbered, and its acquisition parameters are set. The sampling frequency for the resistance strain gauge is 500 Hz, the accelerometer sampling frequency is 1000 Hz, and the pressure / tension sensor sampling frequency is 200 Hz. Low-pass filtering is used for all sensors, and the cutoff frequency is set according to the sensor type: 50 Hz for the strain gauge and 100 Hz for the accelerometer. After configuration, a full-channel data acquisition test is performed, continuously acquiring data for 10 minutes to check whether the data transmission is stable (no packet loss, no abnormal jumps) and whether the output values ​​of the sensor (8) are within the normal range (e.g., no overload on the strain gauge, no zero drift on the accelerometer).

[0042] 3) Functional testing of the central control system Start the central control system, enter the equipment control interface, and test the control functions of each component in sequence: Equipment linkage control: Set the start sequence of water flow drive device → wave generator system 9 → vibration table system, with an interval of ten minutes. After sending the start command, observe whether each device starts according to the set sequence and whether the operating status (speed, frequency, amplitude) is accurately displayed on the interface.

[0043] Parameter adjustment function: During the operation of the water flow drive device, the speed of the axial flow pump 5 is adjusted through the interface, and the data of the flow velocity sensor 8 is observed to change synchronously with the adjustment command, with a response delay of no more than one second. Similarly, the accuracy of wave height adjustment of the wave generator and acceleration adjustment of the vibration table is tested.

[0044] Data storage and interface testing: Simulate 20 minutes of data acquisition and check whether the data is automatically stored to the specified hard drive. The storage format must be compatible with software such as MATLAB and Origin. Test the interface with external data analysis software to ensure that the data can be successfully imported and processed subsequently.

[0045] (II) Implementation of the simulation method (1) Production of scaled-down models Create a scaled-down model based on the criteria of geometric similarity, material similarity, mechanical similarity, and environmental load similarity: Geometric similarity: Based on the actual offshore wind power system, a similarity ratio of 1:100 was determined. The dimensions of the wind turbine base, wind turbine tower 6, and wind turbine blade 7 were reduced proportionally, with a machining accuracy not exceeding ±0.1mm, to ensure that the connection method of each component of the model is consistent with the prototype.

[0046] Material Similarity: Model materials with similar mechanical properties to the prototype materials were selected. The pile foundation model used 45# steel with an elastic modulus of 200GPa, achieving a similarity ratio of 1:1 with the prototype steel. The floating foundation model used aluminum alloy with a density of 2.7g / cm³. 3 By adding counterweights to adjust the density ratio to match that of the prototype, the blade model is made of epoxy resin composite material with an elastic modulus of 3.5 GPa, which matches the similarity ratio of the prototype glass fiber composite material.

[0047] Mechanical similarity: By adjusting the thickness and cross-sectional dimensions of the model's materials, the stiffness and strength of the model are ensured to maintain a similarity ratio with the prototype. Environmental load similarity is achieved by adjusting the parameters applied in subsequent load applications.

[0048] After all the components of the model are manufactured, they undergo rust removal and painting surface treatment. Key dimensions, such as the pile diameter and blade chord length, are also inspected to ensure they meet the design requirements.

[0049] (2) Model calibration and testing Static loading test: Installation auxiliary device: A horizontal loading frame and a vertical loading jack are temporarily fixed at the edge of the rectangular water tank 1. The horizontal loading frame can be raised and lowered in the vertical direction. The horizontal loading frame is connected to the top of the model through a steel cable. A force sensor is installed at the end of the steel cable. The vertical loading jack is attached to the top of the model through a pressure plate.

[0050] Loading and data acquisition: Horizontal and vertical loads were applied in five levels, starting from 20% of the model's design bearing capacity. Each load level was maintained for five minutes, and displacement and stress data of the model under different load levels were collected through sensor 8.

[0051] Data comparison and verification: The collected load-displacement measured data are compared with the finite element calculation values ​​of the corresponding working conditions. If the displacement error exceeds ±10% or the stress error exceeds ±15%, the model is adjusted until the test results match the theoretical values.

[0052] Modal testing: Excitation and Data Acquisition: The central control system inputs a sweep frequency control signal to the vibration table system, controlling the vibration table system to continuously adjust the vibration frequency along a preset frequency range (covering the possible natural frequency range of the model), thus forming a sweep frequency vibration excitation. Vibration response data is acquired by accelerometers installed at key parts of the model.

[0053] Parameter extraction and validation: Spectral analysis of the response data was performed using data analysis software to extract the model's natural frequencies (including first-order bending and torsional frequencies) and mode shapes (including bending and torsional modes). Mode shape extraction was achieved through correlation analysis of multi-point vibration response data. The model's modal parameters were compared with those of actual offshore wind power systems to ensure that the model's dynamic characteristics met similarity requirements. If significant differences existed, the model design was further optimized.

[0054] (3) Model installation Based on the type of base selected for the experiment, install the completed and calibrated scaled-down model onto the corresponding dedicated interface: Pile foundation model: Insert the pile into the pile hole and fill it with a clay-sand mixture. Adjust the installation depth and verticality using a hydraulic positioning clamp to fix the pile top.

[0055] Basic model of the jacket: Secure it to the connection node with bolts, and check the bolt preload torque again.

[0056] Gravity-based foundation model: Placed on a horizontally calibrated installation platform, with the center of gravity aligned with the positioning lines.

[0057] Suction-type foundation model: When in contact with the sealing component, activate the vacuum component to sink the foundation into the simulated soil layer to the preset depth, and then close the vacuum valve.

[0058] Floating foundation model: Placed on the water surface, connected to mooring cables and pretensioned to the design value.

[0059] After the model is installed, check the connection status of sensor 8 again to ensure that there is no looseness, debug the data acquisition system, and confirm that the signals of each sensor 8 are normal.

[0060] 2. Application of Coupled Loads (1) Application of water flow load Start the water flow drive control module in the central control system, input the water flow parameters (flow velocity and direction are set according to the test conditions), and adjust the speed and flow rate of axial flow pump 5 to form a stable water flow field. Monitor the water flow parameters in different areas of the water tank in real time through water flow sensors. After the parameters stabilize and meet the test requirements, keep the water flow drive device running continuously to provide a stable water flow environment for subsequent wave and seismic load application.

[0061] (2) Wave and water flow coupling application After the water flow stabilizes, the wave generator system control module is activated, and wave parameters are set (regular wave, irregular wave, or isolated wave selected according to experimental requirements) to generate the corresponding wave. Wave parameters (wave height, period, wavelength) near the model installation area are monitored by wave sensors, and the pusher plate motion parameters of the wave generator are finely adjusted based on the monitoring data to ensure a stable coupling between the wave and the water flow, maintaining this coupling state for no less than fifteen minutes.

[0062] (3) Coupling of earthquake and wind wave flow After the wave and water flow coupling stabilizes, the shaking table system control module is activated, and seismic wave parameters (sine wave, triangular wave, random wave, or actual earthquake record selected according to the test conditions) are input to simulate seismic action. Vibration parameters are monitored in real time using acceleration sensors fixed to the shaking table surface to ensure that the deviation between the shaking table output and the set seismic wave parameters does not exceed ±5%. Throughout the entire coupled load application process, the model's state is closely observed. If abnormal vibration or signs of instability appear, the test is immediately stopped, the cause investigated, and adjustments made before restarting.

[0063] 3. Data Collection and Analysis (1) Real-time data acquisition During the application of coupled loads, the data acquisition and monitoring system automatically initiates the data acquisition program. Sensors 8 (accelerometers, strain gauges, pressure sensors, tension sensors, etc.) installed at key locations on the model transmit the acquired acceleration, stress-strain, pressure, tension, and other data to the data acquisition card of the central control system at a preset sampling frequency. After preliminary processing such as signal amplification and filtering, the data acquisition card automatically stores the received raw data to a designated hard drive, forming a continuous test data file.

[0064] Meanwhile, high-speed cameras 11, arranged around the water tank, continuously capture the dynamic response process of the model at a set frame rate, covering scenarios such as foundation deformation, tower swaying, blade motion, and the interaction between waves, water flow, and the model. The video data is transmitted in real time to the central control system via a high-speed data transmission line, achieving time synchronization with the data from sensor 8, ensuring that changes in the model's mechanical parameters can be correlated with intuitive dynamic images during subsequent analysis.

[0065] The real-time monitoring interface of the data acquisition system synchronously displays the real-time data curves of each sensor 8 (such as acceleration time history curves and stress change curves) and the real-time video footage transmitted back by the high-speed camera 11. The test personnel can monitor the test progress in real time through the interface, promptly detect abnormal responses of the model (such as excessive vibration and loose parts) and take corresponding measures.

[0066] (2) Data analysis and processing A. Sensor 8 Data Processing After the experiment, the stored sensor 8 data was imported into professional data analysis software such as MATLAB and Origin for systematic processing. The first step was data preprocessing: wavelet denoising algorithm was used to remove environmental interference noise (such as equipment operating noise and electromagnetic interference) from the data; linear interpolation was used to fill in missing data caused by brief interruptions in signal transmission during the acquisition process; and zero drift correction was used to eliminate the zero-point offset error of sensor 8 itself to ensure data accuracy.

[0067] After preprocessing, curves of various physical quantities changing over time are plotted based on the analysis requirements, including but not limited to the acceleration-time curve at the top of the tower, the stress-time curve at key parts of the foundation, and the tension-time curve of the mooring cable, to intuitively present the mechanical response law of the model under coupled loads (such as the transient response at the initial stage of load application and the periodic fluctuations in the steady stage).

[0068] Fast Fourier Transform is used to perform spectral analysis on dynamic data such as acceleration and displacement, extract the frequency components of the response signal, identify the resonant frequencies of the model (such as the first-order bending resonant frequency of the tower and the vibration resonant frequency of the foundation), and determine whether there is a risk of resonance under coupled loads. The extreme values ​​(maximum acceleration, maximum stress), mean and standard deviation of each physical quantity are calculated through time history analysis to quantify the stress and vibration of the model.

[0069] B. Video Data Analysis Video data captured by high-speed camera 11 is imported into image recognition software such as OpenCV, and frame-by-frame analysis is performed using digital image correlation. By tracking the coordinate changes of pre-set markers on the model surface (such as prominent markings on the top of the foundation, the middle of the tower, and the blade tips), the displacement, deformation, and motion trajectory of each part of the model (such as the trajectory of the foundation tilt angle change and the blade swing trajectory) are calculated. This data is then cross-validated with the displacement and strain data collected by sensor 8 to improve the reliability of the analysis results.

[0070] Meanwhile, by observing the details of the interaction between the waves and the model through video footage (such as the angle of wave impact on the foundation and the height of splashing waves), the scouring effect of water flow on the foundation, and the overall swaying posture of the model under seismic loads, combined with mechanical parameter analysis, we can fully understand the stress and deformation mechanism of the model under complex coupled loads.

[0071] C. Comprehensive Security Assessment Combining the data analysis results from Sensor 8 with the conclusions from video analysis, a multi-dimensional safety assessment system is constructed: From the perspective of structural strength, the maximum stress of each key part of the model is compared with the allowable stress of the material to determine whether there is a risk of structural cracking, yielding, or other damage; from the perspective of deformation control, the foundation tilt angle and tower horizontal displacement are checked to see if they exceed the design allowable range; from the perspective of vibration safety, the vibration amplitude of the model is assessed to see if it is within the tolerance threshold for normal operation of the equipment.

[0072] Based on the evaluation results, identify the weak links (such as the middle of the pile body of the pile foundation and the node parts of the jacket foundation) and potential failure modes of the model under coupled loads, and form a complete test analysis report to provide direct test basis for the structural optimization (such as increasing the wall thickness of weak parts and optimizing the foundation connection method) and load-bearing design improvement of actual offshore wind power systems.

[0073] The remaining technical features in the above embodiments can be flexibly selected by those skilled in the art to meet different specific practical needs according to actual circumstances. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims. In the above description, numerous specific details have been set forth to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to implement the present invention. In other instances, to avoid obscuring the present invention, well-known techniques, such as specific construction details, operating conditions, and other technical conditions, have not been specifically described.

[0074] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A wind-wave-current-seismic coupled load simulation device for offshore wind power systems, characterized in that: This includes a comprehensive simulation platform, a model installation area, and a data acquisition and monitoring system; The integrated simulation platform includes a rectangular water tank, a shaking table system, a wave generator system, and a water flow drive device. The rectangular water tank is made of high-strength steel and has a vibration isolation device at the bottom. The shaking table system is installed at the center of the bottom of the rectangular water tank and has three-dimensional vibration capability to simulate sine waves, triangular waves, random waves, and seismic waves from actual earthquake records. The wave generator system is installed at one end of the rectangular water tank to generate regular waves, irregular waves, or isolated waves, and multiple wave generators are coordinated to achieve wave superposition in different directions and frequencies. The water flow drive device consists of multiple axial flow pumps, which are installed at the bottom and side walls of the rectangular water tank to control the water flow speed and direction. Water flow sensors are installed inside the rectangular water tank to monitor water flow parameters in real time. The model installation area is located in a rectangular water tank and is equipped with a special installation structure that adapts to pile foundation models, jacket foundation models, gravity foundation models, suction foundation models, or floating foundation models; resistance strain gauges and acceleration sensors are arranged at the bottom and top of the tower, the root and tip of the fan blades of the scaled-down model of the offshore wind power system. The data acquisition and monitoring system includes several high-speed cameras arranged around a rectangular water tank, a central control system, data acquisition cards and data analysis software installed in the central control system; the data acquisition cards are used to acquire sensor data; the data analysis software integrates data processing algorithms and analysis models for statistical analysis, spectrum analysis, time history analysis and image recognition analysis.

2. The offshore wind power system wind-wave-current-seismic coupled load simulation device according to claim 1, characterized in that: The pile foundation model is a scaled-down model of an offshore wind power system using pile foundations. Resistance strain gauges are arranged at intervals along the length of the pile body, and acceleration sensors are installed on the top of the piles. The special installation structure for the pile foundation in the model installation area includes several pile holes with adjustable depth and verticality. The pile holes are filled with a clay-sand mixture material that simulates the interaction between the pile and the soil.

3. The offshore wind power system wind-wave-current-seismic coupled load simulation device according to claim 1, characterized in that: The jacket foundation model is a scaled-down model of an offshore wind power system using a jacket foundation. The dedicated installation structure for the jacket foundation in the model installation area includes connection nodes and support structures that match the jacket foundation. The support structure is fixedly connected to the bottom of the rectangular water tank. The connection nodes are set on the support structure. The position and size of the bolt holes of the connection nodes are adapted to the jacket foundation. Resistance strain gauges are attached to the connection nodes. Acceleration sensors are installed on the top of the main columns of the support structure.

4. The offshore wind power system wind-wave-current-seismic coupled load simulation device according to claim 1, characterized in that: The gravity foundation model is a scaled-down model of an offshore wind power system using a gravity foundation. The gravity foundation-specific installation structure in the model installation area includes a level-calibrated installation platform. The installation platform is connected to the bottom of a rectangular water tank through pre-embedded anchors. Pressure sensors are evenly arranged on the contact surface between the bottom of the gravity foundation and the installation platform, and an acceleration sensor is arranged at the center of the top of the gravity foundation.

5. The offshore wind power system wind-wave-current-seismic coupled load simulation device according to claim 1, characterized in that: The suction foundation model is a scaled-down model of an offshore wind power system using a suction foundation. Resistance strain gauges and pressure sensors are arranged at intervals along the height direction on the side wall of the suction foundation, and an acceleration sensor is installed on the top. The special installation structure for the suction foundation in the model installation area includes a sealing component, a soil simulation container, and a vacuuming component. The soil simulation container is a cylindrical steel barrel with an open top. The inner wall of the steel barrel is marked with graduation lines. The inside of the steel barrel is filled with silty sand and compacted to a preset density. The bottom of the steel barrel is fixedly connected to a rectangular water tank. The sealing assembly consists of an annular rubber gasket and a metal pressure ring. The annular rubber gasket is embedded in the groove at the top edge of the soil simulation container. The metal pressure ring is connected to the top flange of the soil simulation container by bolts and presses the annular rubber gasket tightly. The upper surface of the annular rubber gasket is tightly fitted with the steel flange face at the bottom of the suction foundation to form a seal. The vacuum assembly includes a vacuum pump, a vacuum gauge, and a vacuum line. One end of the vacuum line is connected to the vacuum valve on the top of the suction foundation through a sealed interface, and the other end is connected to the vacuum pump. The vacuum gauge is connected in series on the vacuum line to monitor the internal vacuum level of the suction foundation.

6. The offshore wind power system wind-wave-current-seismic coupled load simulation device according to claim 1, characterized in that: The floating foundation model is a scaled-down model of an offshore wind power system using a floating foundation. An acceleration sensor is installed at the center of the deck of the floating foundation. The special installation structure for the floating foundation in the model installation area includes multiple anchor points and adjustable mooring lines. Different mooring methods of the offshore wind power system model are simulated by adjusting the pretension and length of the adjustable mooring lines. Tension sensors are arranged at the mooring connection points between the adjustable mooring lines and the floating foundation.

7. A simulation method for a wind-wave-current-seismic coupled load simulation device for an offshore wind power system according to any one of claims 1-6, characterized in that, The steps are as follows: S1. Model Preparation: S1.

1. Based on the criteria of geometric similarity, material similarity, mechanical similarity and environmental load similarity, construct pile foundation models, jacket foundation models, gravity foundation models, suction foundation models or floating foundation models. S1.2 Select the corresponding special installation structure according to the foundation type, and install the scaled-down model of the offshore wind power system in the model installation area; S1.

3. Perform static loading and modal tests, and debug the model and sensors according to the test results to ensure that the connection of each component is reliable and the sensors are working properly. S2, Application of coupled load: S2.1 Start the water flow drive device, adjust the axial flow pump speed and flow rate to form a stable water flow field, and monitor the water flow parameters through the water flow sensor until they meet the test requirements; S2.2 After the water flow stabilizes, start the wave generator system, set the wave parameters, generate regular waves, irregular waves or isolated waves, monitor and fine-tune the wave parameters through wave sensors to form a stable coupling between waves and water flow; S2.3 After the waves and water flow are stably coupled, start the shaking table system, input the parameters of sine wave, triangular wave, random wave or actual earthquake record, simulate the earthquake action, and monitor the vibration parameters through the acceleration sensor set in the shaking table system. S3. Data Acquisition and Analysis: S3.1 During the application of coupled loads, the dynamic response process of the scaled model of the offshore wind power system is captured in real time by a high-speed camera, and the sensor detection data is collected by a data acquisition card. S3.

2. Use data analysis software to filter, denoise, and perform zero drift correction preprocessing on the collected data, and then perform statistical analysis, spectrum analysis and time history analysis. Combine with image recognition analysis to obtain the deformation and motion trajectory of the scaled model of the offshore wind power system. S3.

3. Based on the analysis results, assess the safety of the scaled model of the offshore wind power system under coupled loads, determine the structural damage, the extent to which deformation exceeds the allowable range, and whether the vibration is at an acceptable level, and feed this information back to the system design optimization.

8. The method for simulating wind-wave-current-seismic coupled loads in an offshore wind power system according to claim 7, characterized in that: In S1.3, the static loading test process is as follows: a horizontal loading support and a vertical loading jack are temporarily fixed on a rectangular water tank. The horizontal loading support is connected to the top of the offshore wind power scale-up model through steel cables, and the vertical loading jack is connected to the top of the offshore wind power scale-up model through a pressure plate. Horizontal loads are applied to the offshore wind power scale-up model in stages through the horizontal loading support, and vertical loads are applied to the offshore wind power scale-up model in stages through the vertical loading jack. Displacement and stress data of the offshore wind power scale-up model under different load levels are collected. The collected load-displacement measured data are compared with the finite element calculation values ​​of the corresponding working conditions to verify the similarity between the mechanical response of the offshore wind power scale-up model and the actual offshore wind power system.

9. The method for simulating wind-wave-current-seismic coupled loads in an offshore wind power system according to claim 7, characterized in that: In S1.3, the modal testing process is as follows: the central control system inputs a sweep frequency control signal to the vibration table system, controlling the vibration table system to continuously adjust the vibration frequency along a preset frequency range to form a sweep frequency vibration excitation; the vibration response data of the offshore wind power scaled-down model is collected by an accelerometer installed on the offshore wind power scaled-down model, and the response data is subjected to spectrum analysis using data analysis software to extract the natural frequencies and mode shapes of the offshore wind power scaled-down model, verifying the similarity between the dynamic characteristics of the offshore wind power scaled-down model and the actual offshore wind power system.

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