Simplified calculation method for dynamic response of multi-barrel jacket offshore wind turbine

Abstract

The invention relates to a simplified calculation method for dynamic response of a multi-barrel jacket offshore wind turbine. The simplified calculation method comprises the following steps: establishing a numerical calculation model of the multi-barrel jacket wind turbine; lateral and bottom Winkler moduli and radiation damping of different forms of offshore wind turbine foundations are calculated; the Winkler modulus and radiation damping data obtained through calculation are read, a Winkler spring numerical calculation model considering the foundation-soil body interaction relation is established on the basis of the multi-barrel jacket fan numerical calculation model, a multi-dimensional Winkler spring multi-barrel jacket fan numerical calculation model is obtained, and spring boundary constraint conditions are set according to the external load direction; and wind wave load time history data are imported, and the overall dynamic response calculation of the multi-barrel jacket offshore wind turbine structure is carried out based on the multi-dimensional Winkler spring multi-barrel jacket wind turbine numerical calculation model. Compared with the prior art, the multi-barrel jacket offshore wind turbine dynamic response numerical calculation method is suitable for multi-barrel jacket offshore wind turbine dynamic response numerical calculation of any form in a strong heterogeneous soil layer or a layered foundation, and the calculation efficiency is greatly improved on the premise that it is ensured that the calculation result is accurate.

Description

Technical Field

[0001] The invention relates to the technical field of numerical simulation calculation of offshore wind turbines, and in particular to a simplified calculation method for dynamic response of a multi-barrel jacket offshore wind turbine. Background Art

[0002] The offshore wind power industry is developing towards large-scale and deep-water development. Compared with gravity foundations, single pile foundations, suction bucket foundations and other foundation forms, multi-barrel jacket foundations have the advantages of high rigidity, easy construction and installation, and suitable for water depths above 50m. Since the surface of coastal wind farms is mainly covered with soft soil, and the wind turbine foundation will be subjected to dynamic loads such as wind, waves and earthquakes from the external environment during service, in order to ensure the normal operation of the wind turbine, the current technical challenge lies in how to accurately predict the deformation response of the multi-barrel jacket offshore wind turbine under dynamic loads during the design stage.

[0003] For multi-barrel jacket offshore wind turbines, the dynamic response of the upper structure is mainly affected by the interaction between the foundation and the soil, especially the foundation-soil stiffness. At present, the calculation methods that consider the overall interaction between the upper wind turbine structure, foundation and soil mainly include overall finite element and macro unit methods. Since a large number of trial calculations are required to evaluate and determine the optimal design method of the structure during the design phase, although the overall finite element method can reasonably predict the dynamic response of the multi-barrel jacket wind turbine under dynamic loads such as wind and waves, the numerical modeling process is cumbersome and the calculation efficiency is low, which has a high time cost; the macro unit method is to divide the upper structure and the lower foundation-soil into two parts according to the interface at the top of the foundation, simplify the interaction between the lower foundation and the soil into the stiffness matrix of the top of the foundation, and then use the stiffness of the top of the foundation as the boundary condition, so as to consider the influence of the interaction between the foundation and the soil on the dynamic response of the upper structure. Although this method saves calculation time compared to the finite element method, it is usually only applicable to homogeneous soil layers with constant shear modulus, or geological profiles where the shear model changes approximately linearly with depth. It is difficult to consider strong heterogeneous foundations or layered foundations with obvious modulus differences, and it cannot reflect the nonlinear change relationship between the reaction modulus of the soil on the side of the foundation and the depth. Summary of the invention

[0004] The purpose of the present invention is to provide a simplified calculation method for the dynamic response of a multi-barrel jacket offshore wind turbine suitable for heterogeneous soil layers. The numerical analysis model established based on this method can take into account the foundation-soil interaction relationship in heterogeneous or layered foundations with obvious modulus differences, simplify the modeling and analysis process and effectively improve the calculation efficiency of the numerical model.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A simplified calculation method for dynamic response of a multi-barrel jacket offshore wind turbine comprises the following steps:

[0007] Step a: Based on finite element numerical modeling software, a numerical calculation model of a multi-barrel jacket fan is established;

[0008] Step b: Based on MATLAB programming, calculate the lateral and bottom Winkler modulus and radiation damping of different forms of offshore wind turbine foundations;

[0009] Step c: Based on the interaction module in the finite element numerical modeling software, the Winkler modulus and radiation damping data calculated in step b are read, a Winkler spring numerical calculation model is established on the basis of the multi-barrel jacket fan numerical calculation model, and spring boundary constraints are set according to the external load direction to obtain a multi-dimensional Winkler spring multi-barrel jacket fan numerical calculation model;

[0010] Step d: Import the wind and wave load time history data, and calculate the overall dynamic response of the multi-barrel jacket offshore wind turbine structure based on the multi-dimensional Winkler spring multi-barrel jacket wind turbine numerical calculation model.

[0011] The different forms of offshore wind turbine foundations include suction bucket foundations, large-diameter single pile foundations and circular shallow foundations, and their different forms are determined based on the aspect ratio.

[0012] In step b, the lateral distributed Winkler modulus expression of the offshore wind turbine foundation is specifically:

[0013]

[0014] Among them, k x (h) is the horizontal Winkler modulus at depth h; k z (h) is the Winkler modulus in the vertical direction; k θ (h) is the Winkler modulus in the rotation direction; v s is the Poisson's ratio of soil; E s and E p are the elastic modulus of soil and offshore wind turbine foundation respectively; G s is the elastic shear modulus of the soil; L is the effective burial depth of the offshore wind turbine foundation; D is the diameter of the offshore wind turbine foundation; I p is the moment of inertia of the offshore wind turbine foundation section.

[0015] In step b, the bottom concentrated Winkler modulus expression of the offshore wind turbine foundation is:

[0016]

[0017] Among them, K bxis the Winkler modulus in the horizontal direction of the bottom of the offshore wind turbine foundation; K bz is the vertical Winkler modulus at the bottom of the offshore wind turbine foundation; K bθ is the Winkler modulus of the bottom of the offshore wind turbine foundation in the rotation direction.

[0018] In step b, the side radiation damping expression of the offshore wind turbine foundation is:

[0019]

[0020] Among them, c x , c z and c θ They represent the horizontal, vertical and rotational radiation damping of the offshore wind turbine foundation side; ρ is the soil density; is the soil shear wave velocity; for simplicity, the dimensionless frequency a0 is taken as a constant of 1.

[0021] In step b, the bottom radiation damping expression of the offshore wind turbine foundation is:

[0022]

[0023] Among them, C bx , C bz and C bθ They represent the horizontal, vertical and rotational radiation damping of the bottom of the offshore wind turbine foundation respectively; parameter c rc The specific expression is:

[0024]

[0025] The soil elastic modulus E in the Winkler modulus expression is s and shear modulus G s The modulus value of the soil layer at the current depth is adopted, and the established Winkler spring numerical calculation model is used for the numerical analysis of heterogeneous and layered foundations.

[0026] The step c comprises the following sub-steps:

[0027] Step c1: Based on the interaction module in the finite element numerical modeling software, a Winkler spring numerical calculation model is established on the side and bottom surfaces of the multi-barrel jacket fan numerical calculation model in step a;

[0028] Step c2: read the Winkler modulus and radiation damping data files in step b;

[0029] Step c3: assigning the Winkler modulus and radiation damping to the Winkler spring numerical calculation model established in step c1;

[0030] Step c4: Set the Winkler spring boundary conditions at the lateral and bottom of the offshore wind turbine foundation to constrain the corresponding translational or rotational degrees of freedom, and obtain a multi-dimensional Winkler spring multi-barrel jacket wind turbine numerical calculation model.

[0031] The step d comprises the following sub-steps:

[0032] Step d1: Obtain the wind and wave load time history at the wind turbine hub and the jacket;

[0033] Step d2: Apply the wind and wave load time history in step d1 as an external load to the multi-dimensional Winkler spring multi-barrel jacket wind turbine numerical calculation model;

[0034] Step d3: Based on the dynamic implicit analysis module, the dynamic response calculation of the offshore wind turbine under wind and wave loads is performed.

[0035] The wind and wave load time history is determined based on the reaction force on the jacket wind turbine structure obtained by industry standards or numerical simulation calculations.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The present invention establishes a distributed Winkler spring suction bucket foundation-soil interaction model that can take into account the influence of depth h, which is suitable for strong inhomogeneous soil layers or layered foundations.

[0038] (2) The Winkler modulus calculation formula of the present invention is applicable to suction bucket foundations as well as large-diameter single pile foundations or shallow foundations.

[0039] (3) The present invention takes into account the interaction relationship between the foundation and the soil, and can reasonably reflect its influence on the dynamic response of the upper jacket fan structure.

[0040] (4) Compared with the overall finite element analysis method, the simplified numerical analysis model established in the present invention has higher calculation efficiency and a simpler modeling process while ensuring the reliability of the calculation results. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a flow chart of the method of the present invention;

[0042] Figure 2 This is a schematic diagram of the structure of a pipe frame in a preferred embodiment of the present invention;

[0043] Figure 3 The side level of the suction bucket foundation of the preferred embodiment of the present invention (k x (h)), vertical (k z (h)) and rotation (kθ (h)) The relationship between Winkler modulus and depth h;

[0044] Figure 4 It is a schematic diagram of a multi-dimensional Winkler spring numerical calculation model for an offshore wind turbine suction bucket foundation according to a preferred embodiment of the present invention;

[0045] Figure 5 It is a schematic diagram of a numerical calculation model of a multi-dimensional Winkler spring multi-barrel jacket fan according to a preferred embodiment of the present invention;

[0046] Figure 6 is the equivalent wind and wave load time history curve of the preferred embodiment of the present invention;

[0047] Figure 7 It is a comparison diagram of the acceleration response of the offshore wind turbine tower top, platform center and suction bucket top by finite element (FEA) and multi-spring Winkler simplified calculation method in a preferred embodiment of the present invention;

[0048] Figure 8 It is a comparison diagram between the displacement response finite element (FEA) and the multi-spring Winkler simplified calculation method at the top of the offshore wind turbine tower, the center of the platform and the top of the suction bucket of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0049] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0050] This embodiment provides a simplified calculation method for the dynamic response of a multi-barrel jacket offshore wind turbine. Figure 1 As shown, the following steps are included:

[0051] Step a: Based on the finite element numerical modeling software, a numerical calculation model of the multi-barrel jacket fan is established.

[0052] In this step, the numerical calculation software used for modeling is not limited to ABAQUS, but also includes other finite element or finite difference calculation software that can perform numerical analysis.

[0053] In a preferred embodiment of the present invention, the size of the wind turbine tower top is 17m long × 6m wide × 6m high; the size of the wind turbine platform is 15m long × 15m wide × 1m high; the effective burial depth L of the suction bucket foundation is 12m, the foundation diameter D is 12m, and the wall thickness t is 0.01m; the size and structural diagram of the catheter rack are as shown in Figure 2 The cross-sectional dimensions of the main pipe fittings and supporting pipe fittings of the jacket are shown in Table 1:

[0054] Table 1

[0055]

[0056]

[0057] All parts of the fan are made of Q235 steel with a density of 7850kg / m 3 , elastic modulus E p The mass of the tower top is 210GPa, and the Poisson's ratio v is 0.3. In order to ensure that the mass of the tower top is equivalent to the actual project, the density of the tower top mass block is corrected to 480kg / m 3 , that is, the mass of the tower top is 293.76 tons.

[0058] Step b: Based on MATLAB programming, calculate the lateral and bottom Winkler modulus and radiation damping of different forms of offshore wind turbine foundations.

[0059] Different forms of offshore wind turbine foundations include suction bucket foundations, large diameter single pile foundations and circular shallow foundations, and their different forms are determined based on the length-to-diameter ratio. A circular shallow foundation is one with a length-to-diameter ratio L / D less than 0.1, a suction bucket foundation is generally in the range of about 0.3 to 4, and a large diameter single pile foundation is one with a length-to-diameter ratio L / D greater than 4. This embodiment takes the suction bucket foundation as an example for detailed description.

[0060] Step b includes the following sub-steps:

[0061] Step b1: According to the geometric dimensions of the suction bucket foundation and soil parameters, write a calculation program for the Winkler modulus and radiation damping of the suction bucket foundation at the lateral and bottom sides;

[0062] Step b2: Output the data files of the foundation lateral and bottom Winkler modulus and radiation damping in step b1.

[0063] The expression of the lateral distributed Winkler modulus of the suction bucket foundation is as follows:

[0064]

[0065] Among them, k x (h) is the horizontal Winkler modulus at depth h; k z (h) is the Winkler modulus in the vertical direction; k θ (h) is the Winkler modulus in the rotation direction; v s is the Poisson's ratio of soil; E s and E p are the elastic modulus of soil and suction bucket foundation respectively; G s is the elastic shear modulus of the soil; L is the effective burial depth of the suction bucket foundation; D is the diameter of the suction bucket foundation; I p is the moment of inertia of the suction bucket foundation section.

[0066] The bottom concentrated Winkler modulus expression of the suction bucket foundation is:

[0067]

[0068] Among them, K bx K is the Winkler modulus in the horizontal direction of the bottom of the suction bucket foundation; bz is the vertical Winkler modulus of the bottom of the suction bucket foundation; K bθ It is the Winkler modulus of the suction bucket foundation bottom in the rotation direction.

[0069] The side radiation damping expression of the suction bucket foundation is:

[0070]

[0071] Among them, c x , c z and c θ They represent the radiation damping in the horizontal, vertical and rotational directions of the side of the suction bucket foundation respectively; ρ is the soil density; is the soil shear wave velocity; for simplicity, the dimensionless frequency a0 is taken as 1. In particular, in the above formula, θ The expression is simplified and is only applicable to the case where the basic length-to-diameter ratio of the suction bucket L / D=1. In another embodiment, c θ The complete expression is:

[0072]

[0073] Where ρ is the soil density; A ws and A wce is the projection area of ​​the foundation side wall parallel and perpendicular to the load direction; Δ i is the surface area A of the i-th side of the base wce,i Distance to the axis of rotation; J ws and I wce They are the sum of the polar moments of inertia of the foundation surface that shears the soil in the out-of-plane direction and the sum of the moments of inertia of the foundation surface that squeezes the soil in the direction parallel to the rotation axis; is the soil shear wave velocity; V a and V La is the apparent velocity. The frequency-dependent dynamic damping coefficient c1(ω) is expressed as:

[0074]

[0075] The bottom radiation damping expression of the suction bucket foundation is:

[0076]

[0077] Among them, C bx , C bz and C bθ They represent the horizontal, vertical and rotational radiation damping of the bottom of the suction bucket foundation respectively; parameter c rc The specific expression is:

[0078]

[0079] The soil elastic modulus E in the Winkler modulus expression is s and shear modulus G s Using the modulus value of the soil layer at the current depth, the established Winkler spring numerical calculation model can be used for the numerical analysis of heterogeneous and layered foundations.

[0080] In this embodiment, the soil elastic modulus E s is 10 MPa, the Poisson's ratio of the soil is 0.495 (simulating undrained clay), and the shear modulus of the soil is G s The soil pressure is 3.33MPa and the soil density is 1800kg / m 3 , the soil shear wave velocity is 43.1m / s. The calculated curve of the Winkler modulus of the foundation side with depth h is as follows: Figure 3 As shown, the Winkler modulus at the bottom of the foundation is the horizontal modulus K bx =7.15×10 4 kN / m, vertical modulus K bz =1.24×10 5 kN / m, rotational modulus K bθ =3.28×10 6 kN·m; the radiation damping of the suction bucket foundation side is in the horizontal direction c x =3724kN·s / m 2 , vertical direction c z =2886kN·s / m 2 , rotation direction c θ =40088kN·s; the radiation damping at the bottom of the suction bucket foundation is in the horizontal direction C bx =64871kN·s / m, vertical direction C bz =18806kN·s / m, rotation direction C bθ =3622700 kN·s·m. Output the calculated Winkler modulus and radiation damping data files.

[0081] Step c: Based on the interaction module in the finite element numerical modeling software, read the Winkler modulus and radiation damping data calculated in step b, establish a Winkler spring numerical calculation model based on the multi-barrel jacket fan numerical calculation model, and set the spring boundary constraint conditions according to the external load direction to obtain a multi-dimensional Winkler spring multi-barrel jacket fan numerical calculation model.

[0082] Step c includes the following sub-steps:

[0083] Step c1: Based on the interaction module in the finite element numerical modeling software, a Winkler spring numerical calculation model is established on the side and bottom surfaces of the multi-barrel jacket fan numerical calculation model in step a, such as Figure 4 shown.

[0084] Based on the connector element in the ABAQUS interaction module, the Winkler modulus and radiation damping value in the horizontal, vertical and rotational directions at a point on the suction bucket foundation can be defined simultaneously. In particular, the vertical Winkler springs on the sides of the suction bucket foundation are arranged on both sides of the foundation, thereby providing partial anti-rotation stiffness through the tensile and compressive deformation of the springs on both sides. The bottom of the suction bucket foundation is constrained with the reference point through the Kinematic Coupling function, and the stiffness and radiation damping of the concentrated Winkler spring at the bottom of the foundation are defined at the reference point.

[0085] Step c2: Read the Winkler modulus and radiation damping data files in step b.

[0086] Step c3: Assign the Winkler modulus and radiation damping to the Winkler spring numerical calculation model established in step c1.

[0087] Step c4: Set the lateral and bottom Winkler spring boundary conditions of the suction bucket foundation to constrain the corresponding translational or rotational degrees of freedom. Specifically, constrain the horizontal, vertical and rotational degrees of freedom of the grounded side boundary of the multi-dimensional Winkler spring, and combine the multi-dimensional Winkler spring numerical calculation model of the suction bucket with the upper jacket fan structure to establish a complete multi-dimensional Winkler spring multi-bucket jacket fan numerical calculation model, such as Figure 5 shown.

[0088] Step d: Import the wind and wave load time history data, and calculate the overall dynamic response of the multi-barrel jacket offshore wind turbine structure based on the multi-dimensional Winkler spring multi-barrel jacket wind turbine numerical calculation model.

[0089] Step d includes the following sub-steps:

[0090] Step d1: Obtain the wind and wave load time history at the wind turbine hub and the jacket. In this embodiment, the wind and wave load time history is determined based on the reaction force on the jacket wind turbine structure obtained by industry standards or numerical simulation calculations, such as Figure 6 shown.

[0091] Step d2: Apply the wind and wave load time history in step d1 as an external load to the multi-dimensional Winkler spring multi-barrel jacket wind turbine numerical calculation model.

[0092] Step d3: Based on the dynamic implicit analysis module, the dynamic response calculation of the offshore wind turbine under wind and wave loads is performed.

[0093] In this embodiment, the equivalent wind and wave load time history curve is applied to the wind turbine tower 60m away from the top of the platform, and numerical analysis is performed based on the ABAQUS dynamic implicit analysis module. As a comparison, the overall finite element dynamic response calculation of the offshore wind turbine is performed at the same time, that is, the soil solid unit is established, and the inner and outer walls of the suction bucket are bound to the soil to establish contact. The soil boundary extends 15D horizontally and vertically from the center of the top of the suction bucket foundation. The infinite element boundary is used at the soil boundary to absorb the reflection of the wave generated by the vibration.

[0094] The calculation results of the overall finite element (FEA) and the multi-dimensional Winkler spring multi-barrel jacket fan numerical calculation model of the present invention are compared. Figure 7 and 8 shown. Figure 7 Comparison of vertical acceleration responses of the offshore wind turbine tower top, platform center, and suction bucket foundation top. Figure 8 The displacement response comparison of the top angle of the offshore wind turbine tower, the horizontal displacement of the platform center, and the top angle of the suction bucket foundation is shown in Figure 1. It can be seen that the simplified calculation method proposed by the invention is basically consistent with the overall finite element calculation (FEA) results of ABAQUS. In addition, the calculation time of the simplified method proposed by the invention is greatly shortened compared with the overall finite element (the calculation efficiency is increased by about 20 times), which shows that the simplified method proposed by the invention can maintain a high calculation accuracy while improving the calculation efficiency.

[0095] The simplified calculation method for dynamic response of a multi-barrel jacket offshore wind turbine of the present invention has the following beneficial effects:

[0096] While considering the interaction between the suction bucket foundation and the soil, it can also reflect the influence of depth on the Winkler modulus of the foundation side. Compared with the macro unit method, it is more suitable for the calculation of foundation response in strongly heterogeneous soil layers or layered soils. Compared with the overall finite element (FEA) analysis, it reduces the cost of numerical modeling, and significantly improves the calculation efficiency while ensuring high calculation accuracy. It can be used in any finite element or finite difference numerical calculation software, and the dynamic response of the fan structure can be automatically calculated after inputting the Winkler modulus and damping. It can be applied to the dynamic response calculation of multi-bucket jacket fans in any soil layer foundation and structural form, and has a wide range of practical use.

[0097] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning, or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A simplified calculation method for the dynamic response of a multi-barrel jacket offshore wind turbine, characterized in that: The following steps are involved: Step a: Based on finite element numerical modeling software, a numerical calculation model of a multi-barrel jacket fan is established; Step b: Based on MATLAB programming, calculate the lateral and bottom Winkler modulus and radiation damping of different forms of offshore wind turbine foundations; Step c: Based on the interaction module in the finite element numerical modeling software, the Winkler modulus and radiation damping data calculated in step b are read, a Winkler spring numerical calculation model is established on the basis of the multi-barrel jacket fan numerical calculation model, and spring boundary constraints are set according to the external load direction to obtain a multi-dimensional Winkler spring multi-barrel jacket fan numerical calculation model; Step d: Import the wind and wave load time history data, and calculate the overall dynamic response of the multi-barrel jacket offshore wind turbine structure based on the multi-dimensional Winkler spring multi-barrel jacket wind turbine numerical calculation model.

2. A simplified calculation method for dynamic response of a multi-barrel jacket offshore wind turbine according to claim 1, characterized in that: The different forms of offshore wind turbine foundations include suction bucket foundations, large-diameter single pile foundations and circular shallow foundations, and their different forms are determined based on the aspect ratio.

3. The simplified calculation method for dynamic response of a multi-barrel jacket offshore wind turbine according to claim 1 is characterized in that: In step b, the lateral distributed Winkler modulus expression of the offshore wind turbine foundation is specifically: Among them, k x (h) is the horizontal Winkler modulus at depth h; k z (h) is the Winkler modulus in the vertical direction; k θ (h) is the Winkler modulus in the rotation direction; v s is the Poisson's ratio of soil; E s and E p are the elastic modulus of soil and offshore wind turbine foundation respectively; G s is the elastic shear modulus of the soil; L is the effective burial depth of the offshore wind turbine foundation; D is the diameter of the offshore wind turbine foundation; I p is the moment of inertia of the offshore wind turbine foundation section.

4. A simplified calculation method for dynamic response of a multi-barrel jacket offshore wind turbine according to claim 1, characterized in that: In step b, the bottom concentrated Winkler modulus expression of the offshore wind turbine foundation is: Among them, K bx is the Winkler modulus in the horizontal direction of the bottom of the offshore wind turbine foundation; K bz is the vertical Winkler modulus at the bottom of the offshore wind turbine foundation; K bθ is the Winkler modulus of the bottom of the offshore wind turbine foundation in the rotation direction, v s is the Poisson's ratio of soil; G s is the elastic shear modulus of the soil; L is the effective burial depth of the offshore wind turbine foundation; D is the diameter of the offshore wind turbine foundation.

5. The simplified calculation method for dynamic response of a multi-barrel jacket offshore wind turbine according to claim 1 is characterized in that: In step b, the side radiation damping expression of the offshore wind turbine foundation is: Among them, c x , c z and c θ They represent the horizontal, vertical and rotational radiation damping of the offshore wind turbine foundation side; ρ is the soil density; is the soil shear wave velocity; v s is the Poisson's ratio of soil; G s is the elastic shear modulus of the soil; L is the effective burial depth of the offshore wind turbine foundation; D is the diameter of the offshore wind turbine foundation; for simplicity, the dimensionless frequency a0 is taken as 1.

6. The simplified calculation method for dynamic response of a multi-barrel jacket offshore wind turbine according to claim 1 is characterized in that: In step b, the bottom radiation damping expression of the offshore wind turbine foundation is: Among them, C bx , C bz and C bθ They represent the horizontal, vertical and rotational radiation damping of the bottom of the offshore wind turbine foundation respectively; parameter c rc The specific expression is: v s is the Poisson's ratio of soil; G s is the elastic shear modulus of the soil; L is the effective burial depth of the offshore wind turbine foundation; D is the diameter of the offshore wind turbine foundation; is the soil shear wave velocity; ρ is the soil density; the dimensionless frequency a0 is taken as a constant of 1.

7. A simplified calculation method for dynamic response of a multi-barrel jacket offshore wind turbine according to claim 3 or 4, characterized in that: The soil elastic modulus E in the Winkler modulus expression is s and shear modulus G s The modulus value of the soil layer at the current depth is adopted, and the established Winkler spring numerical calculation model is used for the numerical analysis of heterogeneous and layered foundations.

8. The simplified calculation method for dynamic response of a multi-barrel jacket offshore wind turbine according to claim 1 is characterized in that: The step c comprises the following sub-steps: Step c1: Based on the interaction module in the finite element numerical modeling software, a Winkler spring numerical calculation model is established on the side and bottom surfaces of the multi-barrel jacket fan numerical calculation model in step a; Step c2: read the Winkler modulus and radiation damping data files in step b; Step c3: assigning the Winkler modulus and radiation damping to the Winkler spring numerical calculation model established in step c1; Step c4: Set the Winkler spring boundary conditions at the lateral and bottom of the offshore wind turbine foundation to constrain the corresponding translational or rotational degrees of freedom, and obtain a multi-dimensional Winkler spring multi-barrel jacket wind turbine numerical calculation model.

9. The simplified calculation method for dynamic response of a multi-barrel jacket offshore wind turbine according to claim 1 is characterized in that: The step d comprises the following sub-steps: Step d1: Obtain the wind and wave load time history at the wind turbine hub and the jacket; Step d2: Apply the wind and wave load time history in step d1 as an external load to the multi-dimensional Winkler spring multi-barrel jacket wind turbine numerical calculation model; Step d3: Based on the dynamic implicit analysis module, the dynamic response calculation of the offshore wind turbine under wind and wave loads is performed.

10. A simplified calculation method for dynamic response of a multi-barrel jacket offshore wind turbine according to claim 9, characterized in that: The wind and wave load time history is determined based on the reaction force on the jacket wind turbine structure obtained by industry standards or numerical simulation calculations.

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