Stress calculation method, device and equipment of floating type fan foundation structure and medium

Abstract

The invention relates to a stress calculation method, device, equipment and medium for a floating type draught fan foundation structure, and the method comprises the steps: carrying out the frequency domain potential flow water power analysis of a wet surface element model of a foundation floating body of a floating type draught fan, and obtaining the water power pressure distribution and a water power coefficient; boundary conditions are applied to the simulation model of the floating type wind turbine foundation structure, various working conditions are loaded, finite element analysis is carried out based on hydrodynamic pressure distribution, and various structural stress transfer functions are obtained; based on the hydrodynamic coefficient, performing linear processing on the fan aerodynamic force, the impeller pneumatic torque, the floating body hydrodynamic force and the mooring restoring force of the floating fan and the influence of a fan servo controller on the floating fan, and substituting a linearization result into a motion equation of the floating fan for calculation to obtain a plurality of dynamic response spectrums; and multiplying the structural stress transfer functions by the corresponding dynamic response spectrums, and adding a plurality of multiplied results to obtain a total stress spectrum. The method can improve the efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of offshore wind power generation, in particular to a stress calculation method, device, equipment and medium of a floating wind turbine foundation structure. BACKGROUND

[0002] Offshore wind power generation is an important part of clean energy. Studies have shown that for wind turbines installed in waters with a depth of more than 60 meters, compared with fixed foundations, floating foundation structures are more economical for supporting wind turbines. Floating foundation structure evaluation is an important part of floating wind power research and design, and is directly related to the reliability and safety of floating wind power structures, mainly including the strength and fatigue checking of the foundation structure, and both of which depend on the stress calculation results of the floating foundation structure.

[0003] In the structural strength checking link, the current method mainly obtains the structural stress through the design wave method. This method can well adapt to traditional marine engineering structures by equating the load effect of irregular waves to specific design waves. However, for floating wind turbines, the aerodynamic load of the wind turbine is an important load source for the foundation structure, and the design wave method cannot consider the correlation between the wind turbine load and the wave load, which may lead to over-conservative evaluation of the structural strength, thereby affecting the economy of the floating foundation structure. In the structural fatigue checking link, the current method mainly reconstructs the structural stress by combining the load calculation results of the time-domain integrated coupling dynamics analysis of the floating wind turbine and the stress transfer function of the foundation structure. However, this method has the problem of low efficiency, especially when facing a large number of structural fatigue analysis conditions, the time-consuming calculation will seriously hinder the improvement of engineering iterative design efficiency. SUMMARY

[0004] Therefore, it is necessary to provide a stress calculation method, device, equipment and medium of a floating wind turbine foundation structure that can improve efficiency in view of the above technical problems.

[0005] A stress calculation method of a floating wind turbine foundation structure, the method comprising:

[0006] S101, performing frequency domain potential flow hydrodynamic analysis on a wet surface panel model of a foundation float of a floating wind turbine to obtain hydrodynamic pressure distribution and hydrodynamic coefficients;

[0007] Preferably, the wet surface panel model of the foundation float of the floating wind turbine is a calculation model for simulating and analyzing the behavior of the floating offshore wind turbine foundation structure in the marine environment.

[0008] Preferably, the hydrodynamic pressure distribution refers to the distribution of the magnitude and direction of the pressure of water acting on the surface of the floating wind turbine; and the hydrodynamic coefficient refers to a parameter for describing the quantitative relationship of various hydrodynamic forces acting on the floating wind turbine when moving in water.

[0009] S102, boundary conditions are applied to the simulation model of the floating wind turbine foundation structure, various working conditions are loaded, finite element analysis is performed based on the hydrodynamic pressure distribution, and various structural stress transfer functions are obtained;

[0010] S103, based on the hydrodynamic coefficient, the wind turbine aerodynamic force, the impeller aerodynamic torque, the floating body hydrodynamic force, the mooring restoring force, and the wind turbine servo controller of the floating wind turbine are linearized, and the linearization results are substituted into the motion equation of the floating wind turbine for calculation to obtain various dynamic response spectra;

[0011] Preferably, the motion equation of the floating wind turbine is mainly used to describe the dynamic behavior of the floating wind turbine in the marine environment, including the action and response of various forces acting on the floating wind turbine.

[0012] S104, the structural stress transfer functions are multiplied by the corresponding dynamic response spectra respectively, and the results of multiplying the structural stress transfer functions by the corresponding dynamic response spectra are added to obtain a total stress spectrum.

[0013] In one embodiment, step S102 includes:

[0014] The boundary conditions include the constraints of the hydrostatic restoring stiffness and the mooring restoring stiffness on the simulation model;

[0015] The finite element analysis is performed on the structure having the boundary conditions and the working conditions loaded to obtain a unit wave amplitude-structure stress transfer function σ ζ (ω), a unit tower bottom load-structure stress transfer function σ TwrBsL (ω), a unit mooring tension-structure stress transfer function σ MoorL (ω), a structure displacement-structure stress transfer function σ PtfmDisp (ω), a unit motion velocity-structure stress transfer function σ PtfmVel (ω), and a unit motion acceleration-structure stress transfer function σ PtfmAcl (ω).

[0016] In one embodiment, step S103 includes:

[0017] The linearization of the aerodynamic force and the aerodynamic torque of the fan is as follows:

[0018]

[0019] Where, ΔF aero is the disturbance of the aerodynamic force of the fan; ΔQ aero is the disturbance of the aerodynamic torque of the fan; v eff is the effective wind speed; is the horizontal motion speed of the floating fan foundation structure at the hub height; is the gradient of the aerodynamic force F aero of the fan with respect to the incoming wind speed v, is the gradient of the aerodynamic force F aero of the fan with respect to the rotor speed , is the gradient of the aerodynamic force F aero of the fan with respect to the pitch angle θ p ; is the gradient of the aerodynamic torque Q aero of the fan with respect to the incoming wind speed v, is the gradient of the aerodynamic torque Q aero of the fan with respect to the rotor speed is the gradient of the aerodynamic torque Q aer of the fan with respect to the pitch angle θ p ; is the change of the rotor speed; Δθ p is the change of the pitch angle;

[0020] The calculation formula of the hydrodynamic force ΔF hydro of the floating body is as follows:

[0021]

[0022] Where, ΔF wave,ext is the FK-diffraction force in the hydrodynamic coefficient, M add is the added mass in the hydrodynamic coefficient, B rad is the radiation damping matrix in the hydrodynamic coefficient; is the acceleration of the foundation floating body in each degree of freedom, is the speed disturbance vector of the foundation floating body in each degree of freedom; ΔF wave,vis is the viscous force, and the description formula of ΔF wave,vis is as follows:

[0023]

[0024] Where, is the flow speed of the nth structure of the floating fan in the jth direction, is the unit motion speed of the nth structure of the floating fan in the jth direction, Let n be the drag coefficient of the nth structure of the floating wind turbine in the jth direction. Let be the projected area of ​​the nth structure of the floating wind turbine in the jth direction; ρ represents the standard deviation of the relative velocity between the water flow and the nth structure. w The density of seawater;

[0025] Mooring restoring force ΔF moor The calculation formula is:

[0026] ΔF moor =-C moor Δq

[0027] Among them, C moor Let Δq be the mooring stiffness and Δq be the floating body motion vector.

[0028] The expression for the influence of the wind turbine servo controller on the floating wind turbine is:

[0029]

[0030]

[0031] Where, ω lp This is the cutoff frequency of the low-pass filter; The impeller speed; The impeller speed after low-pass filtering; The velocity of structural motion; The velocity of the structure after low-pass filtering; This is the impeller angular acceleration after low-pass filtering; The acceleration of the structure after low-pass filtering; ΔQ g This represents the change in generator power. This is the proportional gain of the generator torque controller in response to the impeller speed feedback. The integral gain of the generator torque controller for impeller speed feedback; Δθ p This is the change in the pitch angle; The proportional gain of the impeller speed feedback from the propeller pitch angle controller; k is the integral gain of the impeller speed feedback from the propeller pitch angle controller. p,s This is the proportional gain of the propeller pitch angle controller in response to the structural motion velocity feedback.

[0032] In one embodiment, step S103 includes:

[0033] The equation of motion for a floating wind turbine is:

[0034]

[0035] Among them, M struc Indicates structural mass; The acceleration of the floating body in each degree of freedom; B struc Indicates damping; The velocity of the floating body in each degree of freedom; C struc The restoring stiffness matrix is ​​represented by Δq; Δq is the displacement perturbation vector of the floating body in each degree of freedom; ΔF aero ΔF represents the aerodynamic disturbance of the fan. hydro For the hydrodynamics of the floating body; ΔF moor For mooring restoring force; I d The moment of inertia of the impeller and drive shaft; ΔQ is the impeller angular acceleration. aero Impeller aerodynamic torque; ΔQ g N represents the generator torque disturbance. gear This refers to the gearbox transmission ratio;

[0036] Substituting the linearized aerodynamic forces of the wind turbine, the hydrodynamic forces of the floating body, the mooring restoring force, and the influence of the wind turbine servo control on the floating wind turbine into the equation of motion of the floating wind turbine, we obtain:

[0037]

[0038] Where, x s Let u be the state vector of the floating wind turbine; cs Control vector; u ds y is the input vector for environmental disturbance; s A is the output vector; s B represents the structure-state matrix; cs B represents the control input gain matrix; ds Represents the input gain matrix for environmental disturbances; C s Indicates the output matrix; Δy represents the change in the state vector. s This indicates the amount of change in the output vector.

[0039] In one embodiment, step S103 includes:

[0040] The input-output transfer function of the floating wind turbine is obtained by performing a Laplace transform on the motion equations after substituting the linearization result.

[0041] Based on the input-output transfer function and the wind, wave and current environmental conditions, a frequency domain integrated coupled dynamic analysis was performed to obtain various dynamic response spectra.

[0042] Input-output transfer function H s (iω) is:

[0043] H s (iω)=C s(iωI-A s ) -1 [B cs B ds ]

[0044] The formula for frequency domain integrated coupled dynamics analysis is:

[0045] S y (iω)=H s (iω)S u (ω)H s (iω) T

[0046]

[0047] Where I is the identity matrix; ω is the frequency; i represents the imaginary unit; A s B represents the structure-state matrix; cs B represents the control input gain matrix; ds Represents the input gain matrix for environmental disturbances; C s Indicates the output matrix;

[0048] S u (ω) is the external environmental disturbance matrix; S wind (ω) represents the fluctuating wind speed spectrum, also known as the wind spectrum; Wave spectrum; S y (iω) represents the structural dynamic response spectrum.

[0049] In one embodiment, step S104 includes:

[0050] Total stress spectrum σ s The formula for (ω) is:

[0051]

[0052] in, For wave spectrum, S is the unit amplitude-structural stress transfer function; TwrBsL,i (ω) represents the load spectrum at the base of the i-th structure, σ TwrBsL,i (ω) is the unit tower base load-structural stress transfer function of the i-th structure; S MoorL,i (ω) represents the mooring tension spectrum of the i-th structure, σ MoorL,i (ω) is the unit mooring tension-structural stress transfer function of the i-th structure; S PtfmDisp,i (ω) represents the rigid body motion spectrum of the i-th structure, σ PtfmDisp,i (ω) is the structural displacement-stress transfer function of the i-th structure; S PtfmVel,i (ω) represents the velocity spectrum of the i-th structure, σ PtfmVel,i(ω) is the unit velocity-stress transfer function of the i-th structure; S PtfmAcl,i (ω) represents the acceleration spectrum of the i-th structure, σ PtfmAcl,i (ω) is the unit acceleration-stress transfer function of the i-th structure.

[0053] In one embodiment, step S104 is followed by:

[0054] Based on the total stress spectrum, stress extreme value analysis is performed using the generalized extreme value distribution method or the threshold transcendence method to obtain the structural strength verification results of the floating wind turbine.

[0055] And / or, based on the total stress spectrum, the fatigue damage of each structure of the floating wind turbine is calculated using the Dirichlet method to obtain the structural fatigue verification results of the floating wind turbine.

[0056] A stress calculation device for a floating wind turbine foundation structure, the device comprising:

[0057] The first analysis module is used to perform frequency domain potential flow hydrodynamic analysis on the surface element model of the wetted surface of the basic floating body of the floating wind turbine, and to obtain the hydrodynamic pressure distribution and hydrodynamic coefficients.

[0058] The second analysis module is used to apply boundary conditions and load various working conditions to the simulation model of the floating wind turbine foundation structure, and to perform finite element analysis based on the hydrodynamic pressure distribution to obtain various structural stress transfer functions.

[0059] The linearization module is used to linearize the aerodynamic force of the floating wind turbine, the aerodynamic torque of the impeller, the hydrodynamic force of the floating body, the mooring restoring force, and the wind turbine servo controller based on the hydrodynamic coefficient, and substitute the linearization result into the motion equation of the floating wind turbine for calculation to obtain various dynamic response spectra.

[0060] The total stress spectrum acquisition module is used to multiply the structural stress transfer function with the corresponding dynamic response spectrum, and add the results of multiplying each structural stress transfer function with the corresponding dynamic response spectrum to obtain the total stress spectrum.

[0061] A computer device includes a memory and a processor, the memory storing a computer program, characterized in that the processor executes the computer program to implement the steps of the above-described method.

[0062] A computer-readable storage medium, characterized in that it stores a computer program, which, when executed by a processor, implements the steps of the above-described method.

[0063] The aforementioned method, apparatus, equipment, and medium for stress calculation of floating wind turbine foundation structures utilize frequency domain potential hydrodynamic analysis on the wetted surface element model of the floating wind turbine foundation to obtain the hydrodynamic pressure distribution and hydrodynamic coefficients. Boundary conditions and various loading conditions are applied to the simulation model of the floating wind turbine foundation structure, and finite element analysis is performed based on the hydrodynamic pressure distribution. This allows for the acquisition of structural stress transfer functions under different working conditions, which can then be quickly combined with the corresponding dynamic response spectrum (i.e., rapid multiplication with the corresponding dynamic response spectrum). This avoids frequent structural finite element analysis, significantly improves computational efficiency, and thus enhances the efficiency of obtaining the total stress spectrum. Attached Figure Description

[0064] Figure 1 This is a diagram illustrating the application environment of a stress calculation method for a floating wind turbine foundation structure in one embodiment.

[0065] Figure 2 This is a flowchart illustrating the stress calculation method for a floating wind turbine foundation structure in one embodiment;

[0066] Figure 3 This is a schematic diagram of the overall process for stress calculation of a floating wind turbine foundation structure in one embodiment;

[0067] Figure 4 This is a contour plot of the principal stress standard deviation of a floating wind turbine foundation structure in one embodiment;

[0068] Figure 5 This is a structural block diagram of a stress calculation device for a floating wind turbine foundation structure in one embodiment.

[0069] Figure 6 This is an internal structural diagram of a computer device in one embodiment.

[0070] Attached diagram descriptions: 41. Wind turbine side column; 42. Diagonal brace; 43. Non-wind turbine side column; 44. Lower connecting beam; 45. Heave chute; 46. Upper connecting beam. Detailed Implementation

[0071] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0072] The stress calculation method for floating wind turbine foundation structures provided in this application embodiment can be applied to, for example... Figure 1In the application environment shown, terminal 10 interacts with server 20 via a wired / wireless channel. The data storage system stores the data that server 20 needs to process. Server 20 performs frequency domain potential hydrodynamic analysis on the wetted surface element model of the floating wind turbine's foundation, obtaining the hydrodynamic pressure distribution and hydrodynamic coefficients. Server 20 applies boundary conditions and loads various operating conditions to the simulation model of the floating wind turbine's foundation structure, and performs finite element analysis based on the hydrodynamic pressure distribution, obtaining various structural stress transfer functions. Based on the hydrodynamic coefficients, server 20 linearizes the wind turbine's aerodynamic forces, impeller aerodynamic torque, floating body hydrodynamics, mooring restoring force, and the influence of the wind turbine servo controller on the floating wind turbine, and substitutes the linearization results into the floating wind turbine's motion equations for calculation, obtaining various dynamic response spectra. Server 20 multiplies the structural stress transfer functions with their corresponding dynamic response spectra, and adds the results of multiplying each structural stress transfer function with its corresponding dynamic response spectrum to obtain the total stress spectrum. Terminal 10 can be, but is not limited to, various personal computers, laptops, smartphones, tablets, IoT devices, etc. Server 20 can be a single server, a server cluster consisting of multiple servers, or a cloud computing center consisting of multiple servers.

[0073] In one embodiment, such as Figure 2 As shown, a stress calculation method for a floating wind turbine foundation structure is provided, and this method is applied to... Figure 1 Taking server 20 as an example, the explanation includes the following steps:

[0074] S101. Frequency domain potential flow hydrodynamic analysis is performed on the wet surface element model of the basic floating body of the floating wind turbine to obtain the hydrodynamic pressure distribution and hydrodynamic coefficients.

[0075] The wet surface element model of the foundation floating body of the floating wind turbine can be constructed using 3D preprocessing software. This wet surface element model accurately reflects the geometric shape of the foundation floating body.

[0076] Frequency domain potential flow hydrodynamic analysis can be achieved using a potential flow hydrodynamic solver. Potential flow hydrodynamic solvers include, but are not limited to, various software tools used to calculate and analyze the hydrodynamic pressure distribution and hydrodynamic coefficients of a floating body in water. The methods for obtaining the hydrodynamic coefficients and hydrodynamic pressure distribution include, but are not limited to, the methods described in patents 202510069862.8 and 202411982196.9.

[0077] S102. Apply boundary conditions and various loading conditions to the simulation model of the floating wind turbine foundation structure, and perform finite element analysis based on the hydrodynamic pressure distribution to obtain various structural stress transfer functions.

[0078] The simulation model of the floating wind turbine foundation structure includes the external shell, internal compartments, and reinforcing structures such as frames, longitudinal beams, ring beams, and stiffening ribs. During the simulation model construction, material properties are assigned to each structure based on the materials used, and mesh generation is completed. Material properties include, but are not limited to, material density, elastic modulus, and constitutive relations.

[0079] The applied boundary conditions include, but are not limited to, conditions that consider the constraints of still water restoring stiffness and mooring restoring stiffness on the simulation model. Specifically, vertical springs are installed at the bottom of the floating foundation of the floating wind turbine to simulate the constraint effect of still water restoring force on the simulation model, and the spring stiffness is determined according to the still water restoring stiffness matrix; horizontal and vertical springs are installed at the mooring guide points of the floating wind turbine to simulate the constraint effect of mooring restoring force on the simulation model, and the spring stiffness is determined according to the mooring restoring stiffness matrix.

[0080] Loading conditions include, but are not limited to, wave load per unit amplitude, unit tower base load, unit mooring tension, structural displacement, unit velocity, and unit acceleration. When loading conditions are applied, at least one loading condition is applied to the same simulation model. A simulation model with boundary conditions and loading conditions applied can be called a finite element model.

[0081] Finite element analysis (FEM) is the analysis of a simulation model with applied boundary conditions and loads. FEM can be performed using a finite element solver. A finite element solver is a software tool used for numerical simulation and solving complex engineering problems.

[0082] By applying only one operating condition to multiple simulation models, finite element analysis can be performed on each model with applied boundary conditions and operating conditions to obtain the structural stress transfer function corresponding to each operating condition. The structural stress transfer function can be used to describe the relationship between the stress response at a specific location of a floating wind turbine and the external excitation it receives.

[0083] S103. Based on the hydrodynamic coefficient, the aerodynamic force of the floating wind turbine, the aerodynamic torque of the impeller, the hydrodynamic force of the floating body, the mooring restoring force, and the influence of the wind turbine servo controller on the floating wind turbine are linearized. The linearization results are then substituted into the motion equation of the floating wind turbine for calculation to obtain various dynamic response spectra.

[0084] The dynamic response spectrum is used to describe the response of a floating wind turbine under dynamic loads. The number of dynamic response spectra corresponds to the number of loading conditions, and they are one-to-one.

[0085] S104. Multiply the structural stress transfer function by the corresponding dynamic response spectrum, and add the results of multiplying each structural stress transfer function by the corresponding dynamic response spectrum to obtain the total stress spectrum.

[0086] The stress calculation method for the aforementioned floating wind turbine foundation structure involves performing frequency domain potential hydrodynamic analysis on the wet surface element model of the floating body of the foundation to obtain the hydrodynamic pressure distribution and hydrodynamic coefficients. Boundary conditions and various loading conditions are applied to the simulation model of the floating wind turbine foundation structure, and finite element analysis is performed based on the hydrodynamic pressure distribution. This allows for the acquisition of the structural stress transfer function under different working conditions, which can then be quickly combined with the corresponding dynamic response spectrum (i.e., rapid multiplication with the corresponding dynamic response spectrum). This avoids frequent structural finite element analysis, significantly improves computational efficiency, and thus enhances the efficiency of obtaining the total stress spectrum.

[0087] In one embodiment, step S102 includes:

[0088] Boundary conditions were applied to the simulation model, including wave load, unit tower base load, unit mooring tension, structural displacement, unit velocity, and unit acceleration per unit amplitude. The boundary conditions included constraints on the simulation model from still water recovery stiffness and mooring recovery stiffness. Finite element analysis was performed on the wired element model of the structure with the boundary conditions and loading conditions applied, yielding the unit amplitude-structural stress transfer function σ. ζ (ω), Unit tower base load - structural stress transfer function σ TwrBsL (ω), unit mooring tension-structural stress transfer function σ MoorL (ω), structural displacement-structural stress transfer function σ PtfmDisp (ω), unit velocity-structural stress transfer function σ PtfmVel (ω), unit acceleration-structural stress transfer function σ PtfmAcl (ω).

[0089] The application of wave loads at unit amplitude primarily maps the hydrodynamic pressure distribution of the foundation buoy caused by wave diffraction onto the outer surface of the simulation model. Different wave directions must also be considered when applying wave loads at unit amplitude.

[0090] The unit tower base load is applied mainly by applying an axial force and shear force of 1 kN or a bending moment and torque of 1 kN·m at the connection between the wind turbine tower and the foundation float. The unit tower base load is applied in six components: Fx, Fy, Fz, Mx, My, and Mz.

[0091] Applying unit mooring tension mainly involves applying a unit load of 1 kN at the connection between each mooring line and the foundation float. The unit mooring tension is applied in three components: Fx, Fy, and Fz.

[0092] Applying structural displacement mainly involves applying hydrostatic pressure to the outer surface of the finite element model under different displacement states of the floating body. The structural displacement of the floating body is applied separately for the three degrees of freedom: heave, roll, and pitch. The applied displacement amplitude range must be large enough to ensure that it covers the range of motion of the floating body in actual sea conditions.

[0093] Applying a unit velocity primarily maps the hydrodynamic pressure distribution of the base float, caused by the radiation damping force and viscous damping in the radiation effect, onto the outer surface of the simulation model. The float structure's velocity is a cosine variation curve with an amplitude of 1, applied separately for each of the six degrees of freedom.

[0094] Applying unit acceleration primarily maps the hydrodynamic pressure distribution of the basic floating body caused by the added mass component in the radiation effect onto the outer surface of the simulation model; it also applies the inertial force caused by inertia to the center of each structure in the simulation model. The acceleration of the floating body structure is a cosine variation curve with an amplitude of 1, applied separately for each of the six degrees of freedom.

[0095] Wave load at unit amplitude corresponds to the unit amplitude-structural stress transfer function σ ζ (ω); Unit tower base load and unit tower base load-structural stress transfer function σ TwrBsL (ω) corresponds to; unit mooring tension and unit mooring tension-structural stress transfer function σ MoorL (ω) corresponds to; structural displacement and structural displacement-structural stress transfer function σ PtfmDisp (ω) corresponds to; unit velocity and unit velocity-structural stress transfer function σ PtfmVel (ω) corresponds to; unit acceleration and unit acceleration-structural stress transfer function σ PtfmAcl (ω) corresponds.

[0096] In this embodiment, by applying boundary conditions to the simulation model and loading conditions including wave load per unit amplitude, unit tower base load, unit mooring tension, structural displacement, unit velocity, and unit acceleration, finite element analysis is performed on the wire element model of the structure with applied boundary conditions and loaded conditions. This allows the structural stress transfer function under different conditions to be obtained, which can then be quickly combined with the corresponding dynamic response spectrum, i.e., quickly multiplied with the corresponding dynamic response spectrum. This avoids frequent structural finite element analysis, significantly improves computational efficiency, and thus enhances the efficiency of obtaining the total stress spectrum.

[0097] In one embodiment, the aerodynamic forces of the fan and the aerodynamic torque of the impeller are linearized, as shown in the following formula:

[0098]

[0099] Where, ΔF aero ΔQ represents the aerodynamic disturbance of the fan; aero v represents the aerodynamic torque disturbance of the impeller. eff For effective wind speed, v eff It can be calculated using the turbulent rotation sampling method based on the incoming wind speed spectrum; The horizontal speed of the floating wind turbine foundation structure at the hub height. The velocity of the basic floating body and the flexible tower in each degree of freedom It was calculated; For the aerodynamic force of the wind turbine F aero The gradient of the incoming wind speed v, For the aerodynamic force of the wind turbine F aero impeller speed gradient, For the aerodynamic force of the wind turbine F aero At the propeller angle θ p The gradient; The impeller aerodynamic torque Q aero The gradient of the incoming wind speed v, The impeller aerodynamic torque Q aero impeller speed The impeller aerodynamic torque Q aero At the propeller angle θ p The gradient; Δθ is the change in impeller speed. p This is the change in the propeller pitch angle;

[0100] Floating body hydrodynamic ΔF hydro The calculation formula is:

[0101]

[0102] Where, ΔF wave,ext FK represents the diffraction force in the hydrodynamic coefficients, and M represents the diffraction force. add For the added mass in the hydrodynamic coefficient, B rad This is the radiation damping matrix in the hydrodynamic coefficients; The acceleration of the basic floating body in each degree of freedom, The velocity perturbation vector of the basic floating body in each degree of freedom; ΔF wave,vis For viscous forces, ΔF wave,vis The formula is:

[0103]

[0104] in, Let the flow velocity of the nth structure of the floating wind turbine in the jth direction be... For the unit velocity of the nth structure of the floating wind turbine in the j-th direction, Let n be the drag coefficient of the nth structure of the floating wind turbine in the jth direction. Let be the projected area of ​​the nth structure of the floating wind turbine in the jth direction; ρ represents the standard deviation of the relative velocity between the water flow and the nth structure. w The density of seawater;

[0105] Mooring restoring force ΔF moor The calculation formula is:

[0106] ΔF moor =-C moor Δq

[0107] Among them, C moor Let C be the mooring stiffness, and Δq be the floating body motion vector. For the mooring stiffness C... moor The estimation is based on the force balance relationship between the average wind load, still water restoring force, and mooring restoring force to determine the average displacement of the foundation floating body; several small disturbances are applied to the average displacement, and the restoring force of the mooring is calculated using the quasi-static method; a linear fit is performed on the displacement-restoring force, and the slope of the straight line is the mooring stiffness.

[0108] The expression for the influence of the wind turbine servo controller on the floating wind turbine is:

[0109]

[0110] Where, ω lp This is the cutoff frequency of the low-pass filter; The impeller speed; The impeller speed after low-pass filtering; The velocity of structural motion; The velocity of the structure after low-pass filtering; This is the impeller angular acceleration after low-pass filtering; The acceleration of the structure after low-pass filtering; ΔQ g This represents the change in generator power. This is the proportional gain of the generator torque controller in response to the impeller speed feedback. The integral gain of the generator torque controller for impeller speed feedback; Δθ p This is the change in the pitch angle; The proportional gain of the impeller speed feedback from the propeller pitch angle controller; k is the integral gain of the impeller speed feedback from the propeller pitch angle controller. p,s This is the proportional gain of the propeller pitch angle controller in response to the structural motion velocity feedback.

[0111] and It is a first-order low-pass filter.

[0112] For the torque of floating wind turbine generators, a PI (Proportional-Integral) controller is used. A PI controller for the pitch angle of a floating wind turbine.

[0113] In this embodiment, by linearizing the influence of the aerodynamic forces of the floating wind turbine, the aerodynamic torque of the impeller, the hydrodynamic forces of the floating body, the mooring restoring force, and the influence of the wind turbine servo controller on the floating wind turbine, the originally complex nonlinear influence of the aerodynamic forces of the wind turbine, the aerodynamic torque of the impeller, the hydrodynamic forces of the floating body, the mooring restoring force, and the influence of the wind turbine servo controller on the floating wind turbine can be transformed into a linear influence, thereby significantly improving the calculation efficiency of the dynamic response spectrum.

[0114] In one embodiment, step S103 includes:

[0115] The equation of motion for a floating wind turbine is:

[0116]

[0117] Among them, M struc Indicates structural mass; The acceleration of the floating body in each degree of freedom; B struc Indicates damping; The velocity of the floating body in each degree of freedom; C struc The restoring stiffness matrix is ​​represented by Δq; Δq is the displacement perturbation vector of the floating body in each degree of freedom; ΔF aero ΔF represents the aerodynamic disturbance of the fan. hydro For the hydrodynamics of the floating body; ΔF moor For mooring restoring force; I d The moment of inertia of the impeller and drive shaft; ΔQ is the impeller angular acceleration. aero Impeller aerodynamic torque; ΔQ g N represents the generator torque disturbance. gear This represents the gearbox transmission ratio.

[0118] Substituting the linearized aerodynamic forces of the wind turbine, the hydrodynamic forces of the floating body, the mooring restoring force, and the influence of the wind turbine servo control on the floating wind turbine into the equation of motion of the floating wind turbine, we obtain:

[0119]

[0120] Where, x s Let u be the state vector of the floating wind turbine; cs Control vector; u ds y is the input vector for environmental disturbance;s A is the output vector; s B represents the structure-state matrix; cs B represents the control input gain matrix; ds Represents the input gain matrix for environmental disturbances; C s Indicates the output matrix; Δy represents the change in the state vector. s This indicates the amount of change in the output vector.

[0121] Specifically, u cs =[Q g θ p ] T , The matrix elements are composed of dynamic characteristic parameters, including mass, stiffness, damping, and aerodynamic gradient. Specifically:

[0122]

[0123] C s =[0 1]

[0124] M = M struc +M add B = B struc +B rad +B wave,vis +B aero C = C struc +C moor

[0125] Among them, M add For added mass, B rad The radiation damping matrix can be obtained using a potential-flow hydrodynamic solver; B wave,vis For wave viscous damping, B aero is the aerodynamic damping matrix of the wind turbine; I is the identity matrix; 0 represents the zero matrix.

[0126] In one embodiment, step S103 includes: performing a Laplace transform on the motion equations substituted with the linearized result to obtain the input-output transfer function of the floating wind turbine. Based on the input-output transfer function and the wind, wave, and current environmental conditions, a frequency-domain integrated coupled dynamic analysis is performed to obtain various dynamic response spectra.

[0127] Input-output transfer function H s (iω) is:

[0128] H s (iω)=C s (iωI-A s ) -1 [B csB ds ]

[0129] The formula for frequency domain integrated coupled dynamics analysis is:

[0130] S y (iω)=H s (iω)S u (ω)H s (iω) T

[0131]

[0132] Where I is the identity matrix; ω is the frequency; i represents the imaginary unit; A s B represents the structure-state matrix; cs B represents the control input gain matrix; ds Represents the input gain matrix for environmental disturbances; C s S represents the output matrix; u (ω) is the external environmental disturbance matrix; S wind (ω) represents the fluctuating wind speed spectrum; Wave spectrum; S y (iω) represents the structural dynamic response spectrum.

[0133] The equations of motion, after substituting the linearization results, can be written in state-space equation form. The dynamic response spectrum includes the wave spectrum, tower base load spectrum, mooring tension spectrum, floating body rigid body motion spectrum, velocity spectrum, and acceleration spectrum. Wind, wave, and current environmental conditions include the wave spectrum and wind spectrum, which can be obtained through on-site measurements. The tower base load spectrum, mooring tension spectrum, and floating body rigid body motion spectrum can be directly obtained through frequency domain integrated coupled dynamic analysis. The velocity and acceleration spectra can be obtained through floating body rigid body motion spectrum analysis.

[0134] In this embodiment, the input-output transfer function of the floating wind turbine is obtained by performing a Laplace transform on the equation of motion with the linearized result. Based on the input-output transfer function and the wind, wave and current environmental conditions, frequency domain integrated coupled dynamic analysis is performed. This allows for the rapid acquisition of various dynamic response spectra of the floating wind turbine under the combined action of wind, waves and current, providing high-quality load input for the stress calculation of the foundation structure.

[0135] In one embodiment, step S104 includes:

[0136] Total stress spectrum σ s The formula for (ω) is:

[0137]

[0138] in, For wave spectrum, S is the unit amplitude-structural stress transfer function; TwrBsL,i (ω) represents the load spectrum at the base of the i-th structure, σ TwrBsL,i (ω) is the unit tower base load-structural stress transfer function of the i-th structure; S MoorL,i (ω) represents the mooring tension spectrum of the i-th structure, σ MoorL,i (ω) is the unit mooring tension-structural stress transfer function of the i-th structure; S PtfmDisp,i (ω) represents the rigid body motion spectrum of the i-th structure, σ PtfmDisp,i (ω) is the structural displacement-stress transfer function of the i-th structure; S PtfmVel,i (ω) represents the velocity spectrum of the i-th structure, σ PtfmVel,i (ω) is the unit velocity-stress transfer function of the i-th structure; S PtfmAcl,i (ω) represents the acceleration spectrum of the i-th structure, σ PtfmAcl,i (ω) is the unit acceleration-stress transfer function of the i-th structure.

[0139] In this embodiment, the total stress spectrum is obtained by multiplying the structural stress transfer function with the corresponding dynamic response spectrum, and then adding the results of multiplying each structural stress transfer function with the corresponding dynamic response spectrum. This improves the calculation efficiency of structural stress, and allows the total stress spectrum to be used quickly and accurately for structural strength verification and fatigue verification.

[0140] In one embodiment, after step S104, the method includes: performing stress extreme value analysis based on the total stress spectrum using the generalized extreme value distribution method or the threshold transcendence method to obtain the structural strength analysis results of the floating wind turbine; and / or, calculating the fatigue damage of each structure of the floating wind turbine using the Dirichlet method based on the total stress spectrum to obtain the structural fatigue analysis results of the floating wind turbine.

[0141] Among them, the generalized extreme value distribution method is a method used for statistical analysis of extreme values. The generalized extreme value distribution method is based on extreme value theory to model and predict rare but potentially significant extreme events.

[0142] The threshold exceedance method is a statistical method used for extreme value analysis, suitable for studying extreme events that exceed a specific threshold. Compared to the generalized extreme value distribution method, the threshold exceedance method focuses on all data points that exceed the specific threshold, rather than just considering the maximum value within each time period.

[0143] The Dirichlet method is an analytical method based on stress power spectral density used to estimate fatigue damage in structures under random loading. By modeling the stress process as a stochastic process and incorporating statistical theory, the Dirichlet method derives the distribution of cycle counts across different stress amplitude ranges, and then calculates the total fatigue damage.

[0144] In this embodiment, stress extremum analysis is performed using the generalized extreme value distribution method or the threshold transcendence method based on the total stress spectrum, which can accurately capture extreme load events. By using the Dirichlet method based on the total stress spectrum to calculate the fatigue damage of each structure of the floating wind turbine, the cumulative fatigue damage of the structure during long-term service can be estimated more accurately.

[0145] Overall flowchart as follows Figure 3 As shown. The stress calculation methods for floating wind turbine foundation structures mainly include hydrodynamic analysis, finite element analysis of the wind turbine foundation structure, frequency domain integrated coupled dynamic analysis, and stress spectrum calculation.

[0146] The hydrodynamic analysis mainly includes: S1, constructing a basic floating body wetted surface element model of the floating wind turbine; S2, performing frequency domain potential flow hydrodynamic analysis to obtain the hydrodynamic pressure distribution and hydrodynamic coefficients.

[0147] The finite element analysis of the wind turbine foundation structure includes: S3, constructing a finite element model; S4, performing finite element analysis to obtain the stress transfer functions per unit wave amplitude, per unit tower base load, per unit mooring tension, per unit displacement, per unit velocity, and per unit acceleration. S3 includes: S31, constructing a beam-plate-shell model, i.e., constructing a simulation model of the floating wind turbine; S32, applying boundary conditions to the beam-plate-shell model, including constraints from hydrostatic recovery stiffness and mooring recovery stiffness; S33, loading load conditions including per unit wave amplitude wave load, per unit tower base load, per unit mooring tension, structural displacement, per unit velocity, and per unit acceleration onto the beam-plate-shell model.

[0148] The frequency-domain integrated coupled dynamics analysis includes: S5, linearization processing; S6, constructing the state-space equations of the floating wind turbine; S7, solving the state-space equations to obtain the tower base load spectrum, mooring tension spectrum, and floating body rigid body motion spectrum, and further deriving the rigid body motion velocity spectrum and rigid body acceleration spectrum from the floating body rigid body motion spectrum. The rigid body motion velocity spectrum can also be called the velocity spectrum, and the rigid body acceleration spectrum can also be called the acceleration spectrum. S5 includes: S51, linearization of wind turbine aerodynamics; S52, linearization of floating body hydrodynamics; S53, linearization of mooring restoring force; S54, linearization of the influence of the wind turbine servo controller on the floating wind turbine. S7 includes: solving the state-space motion equations of the floating wind turbine to obtain the tower base load spectrum, mooring tension spectrum, and floating body rigid body motion spectrum; further deriving the rigid body motion velocity spectrum and acceleration spectrum from the floating body motion spectrum. The frequency-domain integrated coupled dynamics analysis also includes obtaining wave spectrum, wind spectrum, and ocean current conditions. Stress spectrum calculation includes: S8, total stress spectrum calculation. Simultaneously, strength analysis and fatigue analysis of the wind turbine foundation structure can be performed based on the total stress spectrum. The principal stress standard deviation cloud diagram of the floating wind turbine foundation structure is shown below. Figure 4 As shown, the floating wind turbine foundation structure includes a wind turbine side column 41, a diagonal brace 42, a non-wind turbine side column 43, a lower connecting beam 44, a heave hull 45, and an upper connecting beam 46.

[0149] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0150] Based on the same inventive concept, this application also provides a stress calculation device for a floating wind turbine foundation structure for implementing the stress calculation method for the floating wind turbine foundation structure described above. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of the stress calculation device for a floating wind turbine foundation structure provided below can be found in the limitations of the stress calculation method for the floating wind turbine foundation structure described above, and will not be repeated here.

[0151] In one embodiment, such as Figure 5As shown, a stress calculation device for a floating wind turbine foundation structure is provided, comprising:

[0152] The first analysis module 502 is used to perform frequency domain potential flow hydrodynamic analysis on the surface element model of the wetted surface of the basic floating body of the floating wind turbine, and to obtain the hydrodynamic pressure distribution and hydrodynamic coefficients.

[0153] The second analysis module 504 is used to apply boundary conditions and load various working conditions to the simulation model of the floating wind turbine foundation structure, and to perform finite element analysis based on the hydrodynamic pressure distribution to obtain various structural stress transfer functions.

[0154] The linearization module 506 is used to linearize the aerodynamic force of the floating wind turbine, the aerodynamic torque of the impeller, the hydrodynamic force of the floating body, the mooring restoring force, and the influence of the wind turbine servo controller on the floating wind turbine based on the hydrodynamic coefficient. The linearization result is then substituted into the motion equation of the floating wind turbine for calculation to obtain various dynamic response spectra.

[0155] The total stress spectrum acquisition module 508 is used to multiply the structural stress transfer function with the corresponding dynamic response spectrum, and add the results of multiplying each structural stress transfer function with the corresponding dynamic response spectrum to obtain the total stress spectrum.

[0156] The various modules in the stress calculation device for the aforementioned floating wind turbine foundation structure can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0157] In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 6As shown, the computer device includes a processor, memory, and network interface connected via a system bus. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores the surface element model of the floating body's wetted surface of the floating wind turbine foundation, hydrodynamic pressure distribution, hydrodynamic coefficients, simulation model of the floating wind turbine foundation structure, boundary conditions, operating conditions, structural stress transfer functions, aerodynamic forces of the floating wind turbine, impeller aerodynamic torque, hydrodynamic forces of the floating body, mooring restoring force, the influence of the wind turbine servo controller on the floating wind turbine, linearization results, equations of motion of the floating wind turbine, dynamic response spectrum, and total stress spectrum. The network interface of the computer device is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a method for stress calculation of the floating wind turbine foundation structure.

[0158] Those skilled in the art will understand that Figure 6 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0159] In one embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0160] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above method embodiments.

[0161] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments. It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0162] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0163] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0164] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for stress calculation of a floating wind turbine foundation structure, characterized in that, The method includes: S101. Perform frequency domain potential hydrodynamic analysis on the wet surface element model of the basic floating body of the floating fan to obtain the hydrodynamic pressure distribution and hydrodynamic coefficients. S102. Apply boundary conditions and various loading conditions to the simulation model of the floating wind turbine foundation structure, and perform finite element analysis based on the hydrodynamic pressure distribution to obtain various structural stress transfer functions. S103. Based on the hydrodynamic coefficient, the aerodynamic force of the floating wind turbine, the aerodynamic torque of the impeller, the hydrodynamic force of the floating body, the mooring restoring force, and the influence of the wind turbine servo controller on the floating wind turbine are linearized, and the linearization result is substituted into the motion equation of the floating wind turbine for calculation to obtain multiple dynamic response spectra. S104. Multiply the structural stress transfer function by the corresponding dynamic response spectrum, and add the results of multiplying each structural stress transfer function by the corresponding dynamic response spectrum to obtain the total stress spectrum.

2. The method according to claim 1, characterized in that, Step S102 includes: Boundary conditions are applied to the simulation model, and loads are applied including wave load per unit amplitude, unit tower base load, unit mooring tension, structural displacement, unit velocity, and unit acceleration; the boundary conditions include constraints on the simulation model by still water recovery stiffness and mooring recovery stiffness; Finite element analysis was performed on a wired element model of the structure with applied boundary conditions and loading conditions to obtain the unit amplitude-structural stress transfer function σ. ζ (ω), Unit tower base load - structural stress transfer function σ TwrBsL (ω), unit mooring tension-structural stress transfer function σ MoorL (ω), structural displacement-structural stress transfer function σ PtfmDisp (ω), unit velocity-structural stress transfer function σ PtfmVel (ω), unit acceleration-structural stress transfer function σ PtfmAcl (ω).

3. The method according to claim 1, characterized in that, Step S103 includes: The aerodynamic forces of the fan and the aerodynamic torque of the impeller are linearized using the following formulas: Where, ΔF aero ΔQ represents the aerodynamic disturbance of the fan; aero v represents the aerodynamic torque disturbance of the impeller. eff Effective wind speed; The horizontal speed of the floating wind turbine foundation structure at the hub height; For the aerodynamic force of the wind turbine F aero The gradient of the incoming wind speed v, For the aerodynamic force of the wind turbine F aero impeller speed gradient, For the aerodynamic force of the wind turbine F aero At the propeller angle θ p The gradient; The impeller aerodynamic torque Q aero The gradient of the incoming wind speed v, The impeller aerodynamic torque Q aero impeller speed The impeller aerodynamic torque Q aer o at the propeller angle θ p The gradient; Δθ is the change in impeller speed. p This is the change in the propeller pitch angle; Floating body hydrodynamic ΔF hydro The calculation formula is: Where, ΔF wave,ext FK represents the diffraction force in the hydrodynamic coefficients, and M represents the diffraction force. add Added mass in hydrodynamic coefficients, B rad This is the radiation damping matrix in the hydrodynamic coefficients; The acceleration of the basic floating body in each degree of freedom, The velocity perturbation vector of the basic floating body in each degree of freedom; ΔF wave,vis For viscous forces, ΔF wave,vis The descriptive formula is: in, Let the flow velocity of the nth structure of the floating wind turbine in the jth direction be... For the unit velocity of the nth structure of the floating wind turbine in the j-th direction, Let n be the drag coefficient of the nth structure of the floating wind turbine in the jth direction. Let be the projected area of ​​the nth structure of the floating wind turbine in the jth direction; ρ represents the standard deviation of the relative velocity between the water flow and the nth structure. w The density of seawater; Mooring restoring force ΔF moor The calculation formula is: ΔF moor =-C moor Δq Among them, C moor Let Δq be the mooring stiffness and Δq be the floating body motion vector. The expression for the influence of the wind turbine servo controller on the floating wind turbine is: Where, ω lp This is the cutoff frequency of the low-pass filter; The impeller speed; The impeller speed after low-pass filtering; The velocity of structural motion; The velocity of the structure after low-pass filtering; This is the impeller angular acceleration after low-pass filtering; The acceleration of the structure after low-pass filtering; ΔQ g This represents the change in generator power. This is the proportional gain of the generator torque controller in response to the impeller speed feedback. The integral gain of the generator torque controller for impeller speed feedback; Δθ p This is the change in the pitch angle; The proportional gain of the impeller speed feedback from the propeller pitch angle controller; k is the integral gain of the impeller speed feedback from the propeller pitch angle controller. p,s This is the proportional gain of the propeller pitch angle controller in response to the structural motion velocity feedback.

4. The method according to claim 1, characterized in that, Step S103 includes: The equation of motion for a floating wind turbine is: Among them, M struc Indicates structural mass; The acceleration of the floating body in each degree of freedom; B struc Indicates damping; The velocity of the floating body in each degree of freedom; C struc The restoring stiffness matrix is ​​represented by Δq; Δq is the displacement perturbation vector of the floating body in each degree of freedom; ΔF aero ΔF represents the aerodynamic disturbance of the fan. hydro For the hydrodynamics of the floating body; ΔF moor For mooring restoring force; I d The moment of inertia of the impeller and drive shaft; ΔQ is the impeller angular acceleration. aero Impeller aerodynamic torque; ΔQ g N represents the generator torque disturbance. gear This refers to the gearbox transmission ratio; Substituting the linearized aerodynamic forces of the wind turbine, the hydrodynamic forces of the floating body, the mooring restoring force, and the influence of the wind turbine servo control on the floating wind turbine into the equation of motion of the floating wind turbine, we obtain: Where, x s Let u be the state vector of the floating wind turbine; cs Control vector; u ds y is the input vector for environmental disturbance; s A is the output vector; s B represents the structure-state matrix; cs B represents the control input gain matrix; ds Represents the input gain matrix for environmental disturbances; C s Indicates the output matrix; Δy represents the change in the state vector. s This indicates the amount of change in the output vector.

5. The method according to claim 1 or 4, characterized in that, Step S103 includes: The input-output transfer function of the floating wind turbine is obtained by performing a Laplace transform on the motion equations after substituting the linearization result. Based on the input-output transfer function and the wind, wave and current environmental conditions, a frequency domain integrated coupled dynamic analysis was performed to obtain various dynamic response spectra. Input-output transfer function H s (iω) is: H s (iω)=C s (iωI-A s ) -1 [B cs B ds ] The formula for frequency domain integrated coupled dynamics analysis is: S y (iω)=H s (iω)S u (ω)H s (iω) T Where I is the identity matrix; ω is the frequency; i represents the imaginary unit; A s B represents the structure-state matrix; cs B represents the control input gain matrix; ds Represents the input gain matrix for environmental disturbances; C s S represents the output matrix; u (ω) is the external environmental disturbance matrix; S wind (ω) represents the fluctuating wind speed spectrum, also known as the wind spectrum; Wave spectrum; S y (iω) represents the structural dynamic response spectrum.

6. The method according to claim 1, characterized in that, Step S104 includes: Total stress spectrum σ s The formula for (ω) is: in, For wave spectrum, S is the unit amplitude-structural stress transfer function; TwrBsL,i (ω) represents the load spectrum at the base of the i-th structure, σ TwrBsL,i (ω) is the unit tower base load-structural stress transfer function of the i-th structure; S MoorL,i (ω) represents the mooring tension spectrum of the i-th structure, σ MoorL,i (ω) is the unit mooring tension-structural stress transfer function of the i-th structure; S PtfmDisp,i (ω) represents the rigid body motion spectrum of the i-th structure, σ PtfmDisp,i (ω) is the structural displacement-stress transfer function of the i-th structure; S PtfmVel,i (ω) represents the velocity spectrum of the i-th structure, σ PtfmVel,i (ω) is the unit velocity-stress transfer function of the i-th structure; S PtfmAcl,i (ω) represents the acceleration spectrum of the i-th structure, σ PtfmAcl,i (ω) is the unit acceleration-stress transfer function of the i-th structure.

7. The method according to claim 1, characterized in that, Step S104 is followed by: Based on the total stress spectrum, stress extreme value analysis is performed using the generalized extreme value distribution method or the threshold transcendence method to obtain the structural strength verification results of the floating wind turbine. And / or, based on the total stress spectrum, the fatigue damage of each structure of the floating wind turbine is calculated using the Dirichlet method to obtain the structural fatigue verification results of the floating wind turbine.

8. A stress calculation device for a floating wind turbine foundation structure, characterized in that, The device includes: The first analysis module is used to perform frequency domain potential flow hydrodynamic analysis on the surface element model of the wetted surface of the basic floating body of the floating wind turbine, and to obtain the hydrodynamic pressure distribution and hydrodynamic coefficients. The second analysis module is used to apply boundary conditions and load various working conditions to the simulation model of the floating wind turbine foundation structure, and to perform finite element analysis based on the hydrodynamic pressure distribution to obtain various structural stress transfer functions. The linearization module is used to linearize the aerodynamic force of the floating wind turbine, the aerodynamic torque of the impeller, the hydrodynamic force of the floating body, the mooring restoring force, and the influence of the wind turbine servo controller on the floating wind turbine based on the hydrodynamic coefficient, and then substitute the linearization result into the motion equation of the floating wind turbine for calculation to obtain multiple dynamic response spectra. The total stress spectrum acquisition module is used to multiply the structural stress transfer function with the corresponding dynamic response spectrum, and add the results of multiplying each structural stress transfer function with the corresponding dynamic response spectrum to obtain the total stress spectrum.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the steps of the method according to any one of claims 1 to 7.

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