A semi-coupled aeroelastic modeling method for wind turbine blades considering nonlinear deformation

Abstract

The application discloses a wind turbine blade semi-coupling aeroelastic modeling method considering nonlinear deformation and belongs to the technical field of wind turbine simulation calculation. The application combines calculation parameters used by three-party software, establishes a blade structural load model and a blade corrected aerodynamic model, calculates aerodynamic load and structural load, and superimposes the aerodynamic load, gravity load and centrifugal force load of the blade to serve as external load of a blade nonlinear structure control equation. The external load is taken as a calculation parameter and is brought into a self-constructed iteration scheme, and then simulation calculation of the wind turbine is carried out in a semi-coupling mode. The application adopts the above method, constructs a semi-coupling simulation process of the blade nonlinear structure model and three-party wind turbine simulation software, can calculate higher-precision nonlinear motion response characteristics of an ultra-long flexible wind turbine blade under the same simulation environment and load conditions, and can achieve good effects in preliminary structural design and response evaluation of large wind turbine blades.

Description

Technical Field

[0001] This invention relates to the technical field of wind turbine simulation calculation, and in particular to a semi-coupled aeroelastic modeling method for wind turbine blades that considers nonlinear deformation. Background Technology

[0002] Wind energy, as an inexhaustible and clean energy source, plays a vital role in the global transition to a low-carbon energy structure. To improve power generation efficiency and reduce the cost per kilowatt-hour, wind turbines are increasingly being designed to be larger, with single-unit power exceeding 20MW and blade lengths reaching hundreds of meters. Due to the widespread adoption of lightweight designs, blade flexibility has significantly increased, leading to severe geometric nonlinear problems such as large deformation and rotation in ultra-long flexible blades. This further affects the calculation of blade elastic deformation during rotor rotation, ultimately resulting in inaccurate aeroelastic simulations of wind turbines. Therefore, developing a nonlinear structural dynamics model capable of accurately analyzing the elastic deformation of ultra-long flexible blades is of great significance for the design of large wind turbines.

[0003] Furthermore, current commercial software generally employs low-to-medium precision blade structure simulation strategies such as reduced-order structural models and modal methods, which limit its ability to analyze geometric nonlinear problems such as large deformations of ultra-long flexible blades. Moreover, the packaged code of commercial software is not publicly available, making secondary development difficult. Therefore, designing a simulation environment and load conditions that can simulate the same conditions as commercial wind turbine software, calculate the nonlinear motion response characteristics of blades under the same conditions with higher precision, and intuitively evaluate the response differences between it and commercial wind turbine software, is crucial for judging the rationality of blade design and optimizing blade design. Summary of the Invention

[0004] The purpose of this invention is to provide a semi-coupled aeroelastic modeling method for wind turbine blades that considers nonlinear deformation. This method proposes a semi-coupled aeroelastic modeling method for wind turbine blades that considers nonlinear deformation. By constructing a nonlinear structural model of the blade and a semi-coupled simulation process with commercial wind turbine simulation software, the nonlinear motion response characteristics of the blade with higher accuracy under the same simulation conditions are calculated, and the difference between its response and that of commercial wind turbine software is intuitively evaluated.

[0005] To achieve the above objectives, this invention provides a semi-coupled aeroelastic modeling method for wind turbine blades considering nonlinear deformation, comprising the following steps:

[0006] Step 1: Establish a modified aerodynamic model for the blade. Develop a calculation process for the aerodynamic loads on the airfoil section using blade element-momentum theory. Based on the velocity triangle relationship of the cross-section, derive the normal inflow velocity of the cross-section considering the rotation of the rotor wake. tangential velocity of cross section and the tangential inflow velocity component of the cross section Construct an expression for the relative inflow velocity of the airfoil section. Then calculate the inflow angle of the airfoil section. The angle of attack (AOA) is determined; then, an aerodynamic model of the blade is established using existing correction methods. The normal velocity, tangential velocity components, and rotor speed of the airfoil are obtained from a third-party simulation software, and the relative inflow velocity of the airfoil is calculated. Combined with pitch angle obtained from commercial software The angle of attack of the airfoil section is calculated, and then the result is fed into the calculation process of the modified aerodynamic model. The aerodynamic load of the blade is solved iteratively, and the modified aerodynamic model of the blade is established.

[0007] Step 2: Establish a structured load model for the blade. The structured loads include gravity loads and centrifugal loads. Calculation parameters, including azimuth angles, are obtained from third-party simulation software. Wind turbine speed and the cone angle of the wind turbine and cabin pitch angle Based on the blade mass and rotor speed, the expressions for the gravity and centrifugal loads of the blade are derived respectively; then the moments generated by the gravity load and centrifugal load on the centroid and rigid center of the blade section are calculated to obtain a complete blade structured load model, and then the blade structured load that varies with the rotor rotation in the global coordinate system is calculated.

[0008] Step 3: Superimpose the aerodynamic loads calculated by the blade modified aerodynamic model and the gravity loads and centrifugal loads calculated by the blade structured load model to obtain the complete load of the blade in the global coordinate system, and use the interpolation method to interpolate the blade loads to each element node of the blade nonlinear structural model.

[0009] Step 4: Establish a nonlinear structural dynamic model of the blade. Derive the strain description of the blade's finite rotation using linear velocity and angular velocity vectors. Obtain the constitutive relation matrix of the blade's structural cross-section based on the blade's structural parameters. Using the intrinsic geometry exact beam theory, the kinematic equations, constitutive equations, and equilibrium equations of the blade are derived respectively. The generalized mass matrix of the blade is then derived by combining the kinematic equations. Generalized stiffness matrix and damping dissipation part The expression for combined blade external load; and internal load The governing equations for the nonlinear structural dynamics model of the blade were established, and simulations were performed accordingly.

[0010] Step 5: At each simulation time step, use the blade load calculated in Step 3 as the external load input to the structural model. Constitutive relation matrices for each section of the blade are constructed using blade structural parameters. Based on the governing equations of the blade's nonlinear structural dynamics model, the static equilibrium solution of the blade structural model at the current time step is iteratively calculated using the Newton-Raphson method. The midpoint Euler method is used to solve the nonlinear motion response of the blade at the next time step.

[0011] Preferably, in step one, the process of calculating the aerodynamic load is as follows:

[0012] The normal inflow velocity of the wind turbine blade section is directly obtained using third-party simulation software. tangential inflow velocity of the blade cross section Pitch angle Wind turbine speed Based on wind turbine speed Calculate the tangential velocity of the cross section Based on the modified blade element momentum theory combined with parameter corrections from the unsteady BL dynamic stall model and the Prantl tip loss correction model, the aerodynamic loads on the blade are calculated as follows:

[0013] ;

[0014] ;

[0015] In the above formula, This represents the flapping component of the aerodynamic load. This represents the oscillation component of the aerodynamic load. This represents the spanwise component of the aerodynamic load. It is the dynamic pressure of the airfoil. It is the string length. It is the distance between the centroid and the center of rigidity of the cross section. Indicates the lift coefficient. This represents the drag coefficient, and AOA is the angle of attack. Indicates the angle of inflow.

[0016] Preferably, in step two, the specific process for calculating the structured load is as follows:

[0017] The wind turbine rotor speed is obtained based on simulation software. Azimuth Blade segment quality Cone angle of wind turbine Cabin pitch angle Distance between the centroid and the center of rigidity of the cross section and airfoil inlet angle Formula for calculating gravity load in the overall coordinate system of the blade as follows:

[0018] ;

[0019] ;

[0020] In the above formula, This represents the swing component of the gravitational load. The oscillation component representing the gravitational load, This represents the spanwise component of the gravitational load. This represents the moment produced by gravity about the center of rigidity. Indicates the airfoil section twist angle. The formula is as follows:

[0021] ;

[0022] In the above formula, Indicates the pitch angle; AOA indicates the power angle.

[0023] Centrifugal load The formula is as follows:

[0024] ;

[0025] ;

[0026] In the above formula, This represents the waving component of the centrifugal force load. The oscillation component representing the centrifugal force load, This represents the spanwise component of the centrifugal force load. It represents the moment produced by centrifugal force about the center of rigidity.

[0027] Preferably, in step four, the governing equations of the blade nonlinear structural dynamics model are obtained as follows: The constitutive relation matrix of the blade structural interface is constructed based on the blade structural parameters as follows:

[0028] ;

[0029] Based on the intrinsic geometric exact beam theory, a follower coordinate system is established. With global coordinate system Description of the finite rotational relationship between the cross sections The formula is as follows:

[0030] ;

[0031] ;

[0032] ;

[0033] In the above formula, This represents the initial position vector of any point on the beam. The unit vector representing the axis of rotation. It is the rotational strain quaternion of an intrinsically geometrically accurate beam; It is the rotational variation of an intrinsically geometrically exact beam. These are rotational quaternions and their conjugate complex numbers; thus, the following formula is obtained:

[0034] ;

[0035] In the above formula, The derivative of finite rotation, Represents variation; derivative based on finite rotations and variation Derive the linear strain of the structural model and rotational strain Furthermore, the corrected stress at the midpoint is calculated based on the constitutive equation and the structural capacity dissipation term. and stress moment as follows:

[0036] ;

[0037] in, These are the terms of the constitutive relation matrix; It is the energy dissipation coefficient; the equivalent mass matrix of the blade is derived by combining the equations of motion. Equivalent stiffness matrix and damping dissipation part The expression is given, and finally the governing equations for the nonlinear structural dynamics model of the blade are established as follows:

[0038] ;

[0039] in, For external input load; This refers to the internal load of the structure.

[0040] Preferably, step five involves the following specific process:

[0041] The aerodynamic load, gravity load, and centrifugal load of the blade are superimposed as the external load input to the nonlinear structural control equation of the blade. In each time step, the generalized velocity increment of the governing equations is iteratively solved using the Newton-Raphson method. The convergence condition needs to satisfy the following formula:

[0042] ;

[0043] In the above formula, The error limit is used to calculate the velocity response at the current midpoint, as follows:

[0044] ;

[0045] The blade motion response at the current time step is calculated based on the midpoint Euler method. The specific process is as follows:

[0046] ;

[0047] in, It is a time parameter. The displacement, velocity, and acceleration responses of the blades. Indicates a time step.

[0048] Therefore, the present invention employs the above-mentioned semi-coupled aeroelastic modeling method for wind turbine blades that considers nonlinear deformation, which has the following advantages:

[0049] I. The nonlinear structural model of the blade established in this invention can effectively consider the geometric nonlinear characteristics such as large deformation and large rotation of the structure in the dynamic process, and accurately predict the nonlinear motion response of the ultra-long flexible blade.

[0050] Second, the blade nonlinear structure model of the present invention is based on the intrinsic geometric accurate beam theory. By deriving the blade nonlinear structure control equations using blade linear velocity and angular velocity vectors, it can perform unified interpolation processing for the finite rotation of the solid blade section, avoiding the approximate calculation of section rotation in the traditional geometric accurate beam model, improving the simulation accuracy of ultra-long flexible blades, and the simulation results have more physical meaning.

[0051] Third, the blade semi-coupled aeroelastic modeling method proposed in this invention can reproduce the blade load under the same conditions locally by directly reading a small portion of the simulation parameters from commercial software, thereby achieving the same blade load input in aeroelastic analysis.

[0052] Fourth, the semi-coupled aeroelastic modeling method for blades proposed in this invention has the same load input conditions as commercial software. Therefore, it can simulate the nonlinear motion response of ultra-long flexible blades with higher precision under the same environment, and intuitively evaluate the response difference with commercial wind turbine software. This plays an important role in judging the rationality of blade design and optimizing blade design.

[0053] 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

[0054] Figure 1 The flowchart is a semi-coupled aeroelastic modeling method for wind turbine blades that considers nonlinear deformation according to the present invention.

[0055] Figure 2 This is a schematic diagram of the nonlinear structural model in the semi-coupled aeroelastic modeling method for wind turbine blades that considers nonlinear deformation according to the present invention.

[0056] Figure 3 This is a schematic diagram comparing the blade load results with other calculation results of a semi-coupled aeroelastic modeling method for wind turbine blades that considers nonlinear deformation according to the present invention.

[0057] Figure 4 This is a comparison of the time histories of flapping and oscillating displacements of a wind turbine blade under certain turbulent conditions, based on a semi-coupled aeroelastic modeling method for wind turbine blades that considers nonlinear deformation according to the present invention. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Specific model specifications need to be selected and determined according to the actual specifications of the device, etc. The specific selection calculation method adopts existing technology in the art, and therefore will not be described in detail.

[0059] Example

[0060] like Figures 1-4 As shown, this invention provides a semi-coupled aeroelastic modeling method for wind turbine blades considering nonlinear deformation, comprising the following steps:

[0061] Step 1: Establish a modified aerodynamic model for the blade. Develop a calculation process for the aerodynamic loads on the airfoil section using blade element-momentum theory. Based on the velocity triangle relationship of the cross-section, derive the normal inflow velocity of the cross-section considering the rotation of the rotor wake. tangential velocity of cross section and the tangential inflow velocity component of the cross section Construct an expression for the relative inflow velocity of the airfoil section. Next, the inflow angle of the airfoil section is calculated. Harmony and angle Then, an aerodynamic model of the blade is established using existing correction methods. The normal velocity, tangential velocity components, and rotor speed of the airfoil are obtained from the simulation software, and the relative inflow velocity of the airfoil is calculated. Combined with pitch angle obtained from commercial software The angle of attack of the airfoil section is calculated, and then input into the calculation process of the modified aerodynamic model. The aerodynamic loads of the blade are iteratively solved to establish a modified aerodynamic model of the blade that can reproduce the same aerodynamic loads as commercial software. ;

[0062] The normal inflow velocity of the wind turbine blade section is directly obtained through simulation software. tangential inflow velocity of the blade cross section Pitch angle Wind turbine speed And calculate the tangential velocity of the cross section based on the wind turbine rotation speed. Subsequently, the relative inflow velocity of the airfoil section was calculated based on the modified blade element momentum theory. , inflow angle Angle of attack The parameter expressions were derived, and parameter corrections were made using the unsteady BL dynamic stall model and the Prantl tip loss correction model. The lift coefficient of the airfoil section was obtained by looking up tables based on 2D airfoil wind tunnel data. drag coefficient and torque coefficient The aerodynamic loads on the blades are calculated as follows:

[0063] ;

[0064] ;

[0065] In the above formula, This represents the flapping component of the aerodynamic load. This represents the oscillation component of the aerodynamic load. This represents the spanwise component of the aerodynamic load. It is the dynamic pressure of the airfoil. It is the string length. It is the distance between the centroid and the center of rigidity of the cross section. Indicates the lift coefficient. This represents the drag coefficient, and AOA is the angle of attack. Indicates the angle of inflow.

[0066] Step 2: Establish a structured load model for the blade. The structured loads include gravity loads and centrifugal loads. Calculation parameters, including azimuth angles, are obtained from third-party simulation software. Wind turbine speed and the cone angle of the wind turbine and cabin pitch angle Based on the blade mass and rotor speed, the expressions for the gravity and centrifugal loads of the blade are derived respectively; then the moments generated by the gravity load and centrifugal load on the centroid and rigid center of the blade section are calculated to obtain a complete blade structured load model, and then the blade structured load that varies with the rotor rotation in the global coordinate system is calculated.

[0067] The specific process for calculating structured loads is as follows:

[0068] The wind turbine rotor speed is obtained based on simulation software. Azimuth Blade segment quality Cone angle of wind turbine Cabin pitch angle Distance between the centroid and the center of rigidity of the cross section and airfoil section inlet angle Formula for calculating gravity load in the overall coordinate system of the blade as follows:

[0069] ;

[0070] ;

[0071] In the above formula, This represents the swing component of the gravitational load. The oscillation component representing the gravitational load, This represents the spanwise component of the gravitational load. This represents the moment produced by gravity about the center of rigidity. Indicates the airfoil section twist angle.

[0072] airfoil section twist angle The formula is as follows:

[0073] ;

[0074] In the above formula, Indicates the pitch angle; AOA indicates the power angle.

[0075] Centrifugal load The formula is as follows:

[0076] ;

[0077] ;

[0078] In the above formula, This represents the waving component of the centrifugal force load. The oscillation component representing the centrifugal force load, This represents the spanwise component of the centrifugal force load. It represents the moment produced by centrifugal force about the center of rigidity.

[0079] Step 3: Superimpose the aerodynamic loads calculated by the blade modified aerodynamic model and the gravity loads and centrifugal loads calculated by the blade structured load model to obtain the complete load of the blade in the global coordinate system, and use the interpolation method to interpolate the blade loads to each element node of the blade nonlinear structural model.

[0080] Step 4: Establish a nonlinear structural dynamic model of the blade. Derive the strain description of the blade's finite rotation using linear velocity and angular velocity vectors. Obtain the constitutive relation matrix of the blade's structural cross-section based on the blade's structural parameters. Using the intrinsic geometry exact beam theory, the kinematic equations, constitutive equations, and equilibrium equations of the blade are derived respectively. The generalized mass matrix of the blade is then derived by combining the kinematic equations. Generalized stiffness matrix and damping dissipation part The expression for combined blade external load; and internal load The governing equations for the nonlinear structural dynamics model of the blade were established, and simulations were performed accordingly.

[0081] The governing equations for obtaining the nonlinear structural dynamics model of the blade are as follows:

[0082] The constitutive relation matrix of the blade interface is constructed based on the blade structural parameters as follows:

[0083] ;

[0084] Based on the intrinsic geometric exact beam theory, a follower coordinate system is established. With global coordinate system Description of the finite rotational relationship between the cross sections The formula is as follows:

[0085] ;

[0086] ;

[0087] ;

[0088] In the above formula, It is the rotational strain quaternion of an intrinsically geometrically accurate beam; It is the rotational variation of an intrinsically geometrically exact beam. These are rotational quaternions and their conjugate complex numbers; thus, the following formula is obtained:

[0089] ;

[0090] In the above formula, The derivative of finite rotation, Represents variation; derivative based on finite rotations and variation Derive the linear strain of the structural model and rotational strain Furthermore, the corrected stress at the midpoint is calculated based on the constitutive equation and the structural capacity dissipation term. and stress moment as follows:

[0091] ;

[0092] in, These are the terms of the constitutive relation matrix; It is the energy dissipation coefficient; the equivalent mass matrix of the blade is derived by combining the equations of motion. Equivalent stiffness matrix and damping dissipation part The expression is given, and finally the governing equations for the nonlinear structural dynamics model of the blade are established as follows:

[0093] ;

[0094] in, For external input load; This refers to the internal load of the structure.

[0095] Step 5: At each simulation time step, use the blade load calculated in Step 3 as the external load input to the structural model. Constitutive relation matrices for each section of the blade are constructed using blade structural parameters. Based on the governing equations of the blade's nonlinear structural dynamics model, the static equilibrium solution of the blade structural model at the current time step is iteratively calculated using the Newton-Raphson method. The midpoint Euler method is used to solve the nonlinear motion response of the blade in the next time step. The specific process is as follows:

[0096] The aerodynamic load, gravity load, and centrifugal load of the blade are superimposed as the external load input to the nonlinear structural control equation of the blade. In each time step, the generalized velocity increment of the governing equations is iteratively solved using the Newton-Raphson method. The convergence condition needs to satisfy the following formula:

[0097] ;

[0098] In the above formula, The error limit is used to calculate the velocity response at the current midpoint, as follows:

[0099] ;

[0100] The blade motion response at the current time step is calculated based on the midpoint Euler method. The specific process is as follows:

[0101] ;

[0102] in, It is a time parameter. The displacement, velocity, and acceleration responses of the blades. Indicates a time step.

[0103] A comparative experiment was conducted: The experimental subject was a 15MW wind turbine with blades measuring hundreds of meters in length, simulated using the commercial simulation software DNVGL Bladed. The simulation results are as follows: Figures 3-4 As shown, Figure 3 This indicates that the load results calculated by the semi-coupled aeroelastic method involved in this invention are basically consistent with those of the commercial software DNVGL Bladed; Figure 4 This indicates that the nonlinear response of the ultra-long flexible blade calculated by the method of the present invention differs significantly from that of DNVGL Bladed.

[0104] Therefore, this invention adopts a semi-coupled aeroelastic modeling method for wind turbine blades that considers nonlinear deformation. By constructing a nonlinear structural model of the blade and a semi-coupled simulation process with commercial wind turbine simulation software, the nonlinear motion response characteristics of the blade with higher accuracy under the same simulation conditions are calculated, and the difference between its response and that of commercial wind turbine software is intuitively evaluated.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A semi-coupled aeroelastic modeling method for wind turbine blades considering nonlinear deformation, characterized in that: Includes the following steps: Step 1: Establish a modified aerodynamic model for the blade. Calculate the aerodynamic loads on the airfoil section using blade element-momentum theory. Based on the velocity triangle relationship of the cross-section, derive the normal inflow velocity of the cross-section considering the rotor wake rotation. tangential velocity of cross section and the tangential inflow velocity component of the cross section Construct an expression for the relative inflow velocity of the airfoil section. Then calculate the inflow angle of the airfoil section. Sum of power angles AOA; Then, an aerodynamic model of the blade is established using existing correction methods. The normal velocity, tangential velocity components, and rotor speed of the airfoil are obtained from a third-party simulation software to calculate the relative inflow velocity of the airfoil. ; Combined with pitch angle obtained from commercial software The angle of attack of the airfoil section is calculated, and then the result is fed into the calculation process of the modified aerodynamic model. The aerodynamic load of the blade is solved iteratively, and the modified aerodynamic model of the blade is established. Step 2: Establish a structured load model for the blade. The structured loads include gravity loads and centrifugal loads. Calculation parameters, including azimuth angles, are obtained from third-party simulation software. Wind turbine speed and the cone angle of the wind turbine and cabin pitch angle Based on the blade mass and the rotor speed, the expressions for the gravity and centrifugal force loads of the blades are derived respectively. Then, the torques generated by gravity load and centrifugal load on the centroid and rigidity of the blade section are calculated to obtain a complete blade structured load model, and then the blade structured load that varies with the rotation of the wind turbine in the global coordinate system is calculated. Step 3: Superimpose the aerodynamic loads calculated by the blade modified aerodynamic model and the gravity loads and centrifugal loads calculated by the blade structured load model to obtain the complete load of the blade in the global coordinate system, and use the interpolation method to interpolate the blade loads to each element node of the blade nonlinear structural model. Step 4: Establish a nonlinear structural dynamic model of the blade. Derive the strain description of the blade's finite rotation using linear velocity and angular velocity vectors. Obtain the constitutive relation matrix of the blade's structural cross-section based on the blade's structural parameters. Using the intrinsic geometry exact beam theory, the kinematic equations, constitutive equations, and equilibrium equations of the blade are derived respectively. The generalized mass matrix of the blade is then derived by combining the kinematic equations. Generalized stiffness matrix and damping dissipation part The expression for combined blade external load; and internal load The governing equations for the nonlinear structural dynamics model of the blade were established, and simulations were performed accordingly. Step 5: At each simulation time step, use the blade load calculated in Step 3 as the external load input to the structural model. Constitutive relation matrices for each section of the blade are constructed using blade structural parameters. Based on the governing equations of the blade's nonlinear structural dynamics model, the static equilibrium solution of the blade structural model at the current time step is iteratively calculated using the Newton-Raphson method. The midpoint Euler method is used to solve the nonlinear motion response of the blade at the next time step.

2. The semi-coupled aeroelastic modeling method for wind turbine blades considering nonlinear deformation according to claim 1, characterized in that: In step one, the process of calculating the aerodynamic load is as follows: The normal inflow velocity of the wind turbine blade section is directly obtained using third-party simulation software. tangential inflow velocity of the blade cross section Pitch angle Wind turbine speed Based on wind turbine speed Calculate the tangential velocity of the cross section Based on the modified blade element momentum theory combined with parameter corrections from the unsteady BL dynamic stall model and the Prantl tip loss correction model, the aerodynamic loads on the blade are calculated as follows: ； ； In the above formula, This represents the flapping component of the aerodynamic load. This represents the oscillation component of the aerodynamic load. This represents the spanwise component of the aerodynamic load. It is the dynamic pressure of the airfoil. It is the string length. It is the distance between the centroid and the center of rigidity of the cross section. Indicates the lift coefficient. This represents the drag coefficient, and AOA is the angle of attack. Indicates the angle of inflow.

3. The semi-coupled aeroelastic modeling method for wind turbine blades considering nonlinear deformation according to claim 1, characterized in that: In step two, the specific process for calculating the structured load is as follows: The wind turbine rotor speed is obtained based on simulation software. Azimuth Blade segment quality Cone angle of wind turbine Cabin pitch angle Distance between the centroid and the center of rigidity of the cross section and airfoil section inlet angle Formula for calculating gravity load in the overall coordinate system of the blade as follows: ； ； In the above formula, This represents the swing component of the gravitational load. The oscillation component representing the gravitational load, This represents the spanwise component of the gravitational load. This represents the moment produced by gravity about the center of rigidity. Indicates the airfoil section twist angle. The formula is as follows: ； In the above formula, Indicates the pitch angle; AOA indicates the power angle. Centrifugal load The formula is as follows: ； ； In the above formula, This represents the waving component of the centrifugal force load. The oscillation component representing the centrifugal force load, This represents the spanwise component of the centrifugal force load. It represents the moment produced by centrifugal force about the center of rigidity.

4. The semi-coupled aeroelastic modeling method for wind turbine blades considering nonlinear deformation according to claim 1, characterized in that: In step four, the governing equations of the blade's nonlinear structural dynamics model are obtained as follows: The constitutive relation matrix of the blade's structural interface is constructed based on the blade's structural parameters as follows: ； Based on the intrinsic geometric exact beam theory, a follower coordinate system is established. With global coordinate system Description of the finite rotational relationship between the cross sections The formula is as follows: ； ； ； In the above formula, This represents the initial position vector of any point on the beam. The unit vector representing the axis of rotation. It is the rotational strain quaternion of an intrinsically geometrically accurate beam; It is the rotational variation of an intrinsically geometrically exact beam. These are rotational quaternions and their conjugate complex numbers; thus, the following formula is obtained: ； In the above formula, The derivative of finite rotation, Indicates variation; Derivative based on finite rotation and variation Derive the linear strain of the structural model and rotational strain Furthermore, the corrected stress at the midpoint is calculated based on the constitutive equation and the structural capacity dissipation term. and stress moment as follows: ； in, These are the terms of the constitutive relation matrix; It is the energy dissipation coefficient; the equivalent mass matrix of the blade is derived by combining the equations of motion. Equivalent stiffness matrix and damping dissipation part The expression is given, and finally the governing equations for the nonlinear structural dynamics model of the blade are established as follows: ； in, For external input load; This refers to the internal load of the structure.

5. The semi-coupled aeroelastic modeling method for wind turbine blades considering nonlinear deformation according to claim 4, characterized in that: The specific process in step five is as follows: The aerodynamic load, gravity load, and centrifugal load of the blade are superimposed as the external load input to the nonlinear structural control equation of the blade. In each time step, the generalized velocity increment of the governing equations is iteratively solved using the Newton-Raphson method. The convergence condition needs to satisfy the following formula: ； In the above formula, The error limit is used to calculate the velocity response at the current midpoint, as follows: ； The blade motion response at the current time step is calculated based on the midpoint Euler method. The specific process is as follows: ； in, It is a time parameter. The displacement, velocity, and acceleration responses of the blades. Indicates a time step.

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