CN116484671A - Fine analysis method for full-coupling dynamic response of wind turbine blade - Google Patents
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Abstract
The invention discloses a wind turbine blade full-coupling dynamic response refined analysis method, which aims at the defects that in the load simulation process, the load consideration is incomplete, and the time-varying movement of a blade is ignored in the refined analysis process in the existing blade design analysis methods in the industry and academia, on one hand, the load simulation calculation is carried out by adopting a full-coupling method which can simultaneously consider the influences of aerodynamics, hydrodynamics, structural dynamics, electromechanical servo control dynamics, soil-structure interaction and the like, so as to simulate the real stress mode of the offshore wind turbine blade under the actual working condition; on the other hand, the concentrated force and concentrated moment obtained by integrated simulation are dynamically mapped to a series of nodes of the deformed three-dimensional finite element blade model at each time step, so that the dynamic coupling between the variable deformation of the blade and the applied load is realized, and the unreasonable way of directly applying the static limit load to the undeformed blade is overcome.
Description
Technical Field
The invention relates to the technical field of renewable energy sources and wind power generation, in particular to a wind turbine blade full-coupling dynamic response refined analysis method suitable for floating type offshore wind turbine blade design.
Background
The loads to which a wind turbine blade is subjected in a service environment can be categorized into two types, one type being aerodynamic loads due to air flow and its interaction with the blade and the other type being inertial loads generated by gravity, centrifugal forces, coriolis forces, vibrations, servo control (pitch, yaw, brake) and movement of the support structure. Among these, aerodynamic loads are the most critical loads carried by the fan blades. According to the difference of the pneumatic load calculation methods, the design analysis methods of the fan blade can be divided into two types: one is a Computational Fluid Dynamics (CFD) based method, which has the advantage of simulating the flow field with high fidelity, and the disadvantages of high computational cost, numerical problems and difficulty in achieving integration. The other is an engineering scale method based on the phyllotoxin momentum theory (BEM), and the precision is not high as CFD, but the method is efficient, accurate and mature, and is convenient for realizing integration. In the wind turbine industry, aerodynamic loads on the blades are calculated using BEM-based engineering models and coupled with the structural power response of the entire wind turbine system using simulation tools such as OpenFAST, bladed and HAWC 2. However, while blade structural dynamics calculations for these tools are typically based on a simplified beam model suitable for preliminary design, it is necessary to employ a more detailed three-dimensional shell or solid finite element model for detailed structural analysis from macrostructure to composite layer dimensions to verify final design and to enhance understanding of structural performance. Up to now, students at home and abroad have conducted a great deal of research work based on this and have attempted to deeply recognize the mechanical response of the blade under different conditions by evaluating the structural integrity, buckling, composite failure, damage, and stress/strain distribution of the blade. However, on the one hand, the industry conventional split design method cannot take into account the full coupling of loads during the blade load simulation process; on the other hand, in the process of carrying out full-coupling refined analysis on the wind turbine blades in the international academy, static limit load at a certain moment in the time domain is directly applied to the three-dimensional finite element model, the deformation of the blades which occurs before the limit load occurs is ignored, and the method is only aimed at the onshore wind turbine. Because of inadequate knowledge of the dynamic response of the blade and the simplifications of the load assumptions, existing design analysis methods can only improve the safety factor to avoid damage to the components during service as much as possible. Frequent offshore wind blade engineering accidents, however, indicate that this seemingly conservative approach is not safe and reasonable. In order to face the new challenges brought by the concept of hundred-meter-scale large blades and floating fans under the development trend of large-scale wind power and deep hydration of the sea, a set of reasonable blade design analysis method and evaluation system must be established.
Disclosure of Invention
In order to overcome the defects of incomplete load consideration and neglect of time-varying movement of the blade in the process of carrying out fine analysis in the existing design method, the invention provides a technical scheme of a wind turbine blade full-coupling dynamic response fine analysis method, equipment and medium.
A wind turbine blade full-coupling dynamic response refined analysis method comprises the following steps:
step 1, performing a series of integrated load simulation on various load working conditions by using a full-coupling dynamic simulator so as to obtain a blade structure dynamic response capable of coupling the dynamics of the whole wind turbine system;
step 2, enabling the full-coupling dynamic simulator to output time-varying displacement of a beam model blade analysis node in a local blade coordinate system and coupling structural dynamics reaction load comprising external aerodynamic load and inertial load;
step 3, carrying out coordinate transformation and de-integration operation, converting a local blade coordinate system into a global blade coordinate system, and converting a reaction load into an equivalent concentrated external load;
step 4, mapping the concentrated load acting on the blade analysis nodes under the whole coordinate system of the blade to a series of finite element nodes of the three-dimensional finite element model of the blade according to a reasonable method by a dynamic mapping algorithm at each time step;
and 5, performing quasi-static or transient analysis considering the large deformation effect on the high-fidelity blade finite element model by utilizing a general finite element program, so as to obtain a refined finite element analysis result of the blade at each time step, and feeding back the spatial position change of the three-dimensional blade geometry structure to the dynamic mapping algorithm in the step 4 at each time step to realize dynamic iteration solution of the time domain.
Furthermore, in the step 1, after the external environmental condition parameters and the internal condition parameters of the fan are input, the integrated solution which can simultaneously consider aerodynamics, hydrodynamics, soil-structure interaction, structural dynamics and servo control dynamics is realized in the fully-coupled dynamic simulator.
Further, the step 2 includes: setting an output coordinate system of the fully-coupled dynamic simulator requested in a time domain as a local blade coordinate system considering local structure pretwisting and local deflection of the blade, and setting output parameters as follows: the locally deforming blade, which evolves over time and space, couples the blade structure reaction load, including aerodynamic loads and inertial loads from structural dynamics.
Further, the step 3 includes: discrete reaction forces and reaction bending moments at different blade span sections in a local blade coordinate system are firstly converted from the local blade coordinate system to a global blade coordinate system specified in international standards, and then the local blade coordinate system (x L ，y L ，z L ) The conversion to the global blade coordinate system (XB, YB, ZB) may be represented by the following equation:
wherein θ 1 And theta 2 Respectively representing the local roll and pitch deflection of a given blade section in radians; gamma represents the structural pretwist angle in degrees;
subsequently, each blade analysis node in the global blade coordinate system obtained after the coordinate transformation operation is performedThe reaction load R at the location is subjected to a de-integration operation, and decomposed in the tip-to-root direction, so as to obtain a concentrated equivalent external load L acting on a given blade analysis node i, assuming that the blade analysis node closest to the tip is i max Then:
further, the step 3 further includes: if the global blade coordinate system where the equivalent concentrated load is located is inconsistent with the global coordinate system of the established three-dimensional blade finite element model, the global blade coordinate system is further converted into the global coordinate system of the established three-dimensional high-fidelity blade finite element model, so that the loading is easy.
Further, the step 4 includes: the concentrated forces and moments on each given beam unit blade analysis node are dynamically mapped to a series of three-dimensional finite element model nodes within the corresponding blade segment between that node and the next node to the blade tip at each time step by means of a developed dynamic mapping algorithm, thereby maintaining the mechanical balance of concentrated equivalent loads on each section.
Further, the step 4 specifically includes: for a given blade analysis node i of the beam unit model at a certain time step, assuming that the distance from the node i to the blade root along the direction of the variable pitch axis of the blade is r, the coordinate of the node is (X i ,Y i R) and the flapwise, edgewise forces acting on it during this time step are F respectively X ,i,F Y,i And M Z,i The corresponding segment of the three-dimensional finite element model from i to the next blade analysis node pointing to the tip has N nodes, for a coordinate (X j ,Y j ,Z j ) Is given a node force f in the shimmy direction X,j And node force f in the flapwise direction Y,j Obeying a linear distribution in relation to its coordinates, whereas the axial node force f Z,j The average distribution can establish the following mechanical balance conditions:
wherein X is 0 ＝X j -X i ，Y 0 ＝Y j -Y i ；k 1 To k 7 To obtain the unknown coefficients, they can be obtained from linear algebraic calculations.
Further, the step 5 includes: the method adopts a general finite element program to conduct quasi-static or transient analysis considering large deformation effect, namely geometrical nonlinearity, on one hand, various fine finite element analyses including stress strain, fatigue, failure, buckling and fracture of the whole and partial components of the blade can be conducted, time domain response and evaluation indexes of the blade structure and the material concerned are extracted, and on the other hand, the finite element program automatically calls an interface program at each time step, so that the spatial position change of the three-dimensional blade geometry relative to the undeflected position is transferred and fed back to a dynamic mapping algorithm, and the time domain dynamic iterative solution is realized.
Compared with the prior art, the invention has the following beneficial technical effects:
the existing engineering design analysis method cannot realize time domain refined dynamic analysis on the high-fidelity offshore wind turbine blade finite element model under the dynamic load effect influenced by coupling aerodynamics, structural dynamics, hydrodynamics, electromechanical servo control dynamics and soil-structure interaction. The simplified load simulation method and the lack of knowledge of the real dynamic response of the blade lead the designer to avoid the damage of the blade in the service process as much as possible only by blindly improving the safety coefficient, and frequent engineering accidents show that the method is not safe and reasonable. The algorithm for carrying out the refined dynamic response analysis on the three-dimensional high-fidelity blade finite element model under the integrated frame provided by the invention realizes the refined analysis of the full-coupling dynamic response of the offshore wind power blade, and provides a feasible and reliable technical support for the investigation and evaluation of the time-varying stress/strain distribution and the dynamic buckling behavior of the offshore wind power blade under the actual working condition, as well as the multi-scale analysis work such as the fatigue, failure and fracture behavior of the composite material. On one hand, the technical problems that complex turbulence wind conditions, real servo control strategies (blade pitch, cabin yaw and shutdown) of a complete machine system, coupling action between lower structure movements (such as pile-soil interaction and six-degree-of-freedom movements of a floating body) and loads borne by an upper blade structure and the like cannot be considered in the load simulation process are solved; on the other hand, the dynamic coupling between the large deformation of the blade and the applied load is realized, and the unreasonable practice of applying static limit load on the undeformed blade is overcome.
Drawings
FIG. 1 is a modeling flow chart of a first embodiment;
FIG. 2 is a schematic view showing two-dimensional projection of a three-dimensional geometric model of a 5MW offshore wind turbine blade in accordance with the first embodiment;
FIG. 3 is a detailed modeling schematic of a composite laminate structure for a blade in accordance with one embodiment;
FIG. 4 is a schematic diagram of a high-fidelity three-dimensional finite element model based on layered shell elements in the first embodiment;
FIG. 5 is a schematic diagram of a fixed and floating type integrated model of an offshore wind turbine in the first embodiment, wherein the left side of the diagram is the fixed type integrated model of the offshore wind turbine, and the right side of the diagram is the floating type integrated model of the offshore wind turbine;
FIG. 6 is a schematic diagram of a fine analysis framework of the full coupling dynamic response of an offshore wind turbine blade in the second embodiment;
FIG. 7 is a schematic diagram of a vane coordinate system defined by the second China boundary Standard DNVGL-ST-0376;
FIG. 8 is a schematic diagram of a three-dimensional Fidelity blade finite element model coordinate system in accordance with a second embodiment;
fig. 9 is a diagram showing the time domain refinement analysis result (von Mises stress distribution) in the second embodiment.
Detailed Description
The following description of the technical solutions in the embodiments of the present application will be made clearly and completely with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.
It is noted that unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
Example 1
Referring to fig. 1, before performing a wind turbine blade full-coupling dynamic response refined analysis method, modeling is required, and the modeling process is as follows:
a, establishing a three-dimensional high-fidelity blade finite element model
As shown in fig. 2 and 3, defining two-dimensional airfoil, chord length, torsion angle, three-dimensional geometric shape, shear web position and other complex geometric shapes of the wind turbine blade, physical mechanical parameters such as type, density, strength, elastic modulus, composite material failure criterion related parameters and the like of constituent materials, and layering sequence, direction, thickness and the like of laminated plate composite material structures in various components such as a blade leading edge, a leading edge panel, a trailing edge panel, a girder, a shear web and the like, establishing a high-fidelity three-dimensional finite element model based on layered shell units or solid units, and introducing general finite element analysis software such as ANSYS or Abaqus for subsequent refinement analysis, as shown in fig. 4.
b, establishing a complete machine integrated model considering fidelity and calculation cost
As shown in fig. 5, an offshore wind turbine integrated model is built in wind turbine simulation design software, and comprises a rotor cabin assembly (RNA), corresponding servo control strategies (blade pitch, cabin yaw, brake, shutdown), a tower and a lower structure (a fixed fan is a supporting structure, and a floating fan is a floating platform and a mooring system). The blade model can be simplified based on different structural dynamics calculation methods, including calculation methods based on Euler-Bernoulli beam theory and hypothesis mode superposition methods and calculation methods based on geometric accurate beam theory (GEBT) and Legendre Spectrum Finite Element (LSFE) capable of considering complete geometric nonlinearity.
c, establishing an external environment model
According to international specifications such as IEC and DNV, reasonable wind field parameters (wind speed, wind direction, wind spectrum, turbulence degree and the like), wave field parameters (sense wave height, spectrum peak frequency, wave direction, wave spectrum and the like) and ocean current model parameters (flow speed, flow speed distribution and the like) are selected to simulate external environment conditions such as wind, wave, flow and the like so as to calculate external environment loads in integrated simulation. In addition, soil parameters are determined, and soil-structure interactions of a specific site are described by reasonable pile-soil models and anchor-soil models. For example, for a single pile foundation of a fixed wind turbine, the single pile foundation can be regarded as a horizontal loaded pile, a distributed nonlinear spring is adopted to describe the relation between a unit pile long soil counterforce p above a rotation point and a pile body horizontal displacement y, and the influence of a pile periphery soil body destruction mechanism on a p-y curve is considered; and a concentrated nonlinear rotary spring is arranged to describe the relationship between the soil counter moment M at the rotation point and the rotation point rotation angle theta. For anchor-soil interactions of a floating wind turbine, foundation flexibility can be described in a way that linearizes a 6 x 6 stiffness matrix by providing a set of translation, rotation, and translation-rotation coupling springs at each anchor-soil interface.
Example two
Referring to fig. 6, a method for finely analyzing a fully coupled dynamic response of a wind turbine blade includes: the full-coupling dynamic simulator, the coordinate transformation algorithm, the dynamic mapping algorithm and the finite element analysis code comprise the following steps:
step 1, performing a series of integrated load simulation on various load working conditions by using a fully-coupled dynamic simulator so as to obtain a blade structure dynamic response capable of coupling the dynamics of the whole wind turbine system, wherein the method specifically comprises the following steps of:
firstly, external environmental condition parameters such as wind, wave, ocean current and soil parameters, internal condition parameters such as wind turbine configuration and operation modes and the like are input into fully-coupled dynamic simulators such as open source wind turbine design software OpenFAST and commercial wind turbine design software Bladed and HAWC2, the embodiment specifically adopts OpenFAST as the fully-coupled dynamic simulators, wherein blade structure dynamics calculation adopts an ElastoDyn module, and integrated solving capable of simultaneously considering aerodynamics, hydrodynamics, structural dynamics (including soil-structure interaction) and electrical system (servo) dynamics is performed so as to consider coupling of external loads and interaction among external loads, a control system and internal structure response, as shown in fig. 6.
Step 2, enabling the fully-coupled dynamic simulator to output time-varying displacement of a beam model blade analysis node in a local blade coordinate system and to couple structural dynamics reaction loads including external aerodynamic loads and inertial loads, wherein the method specifically comprises the following steps:
setting an output coordinate system of the fully-coupled dynamic simulator requested in a time domain as a local blade coordinate system considering local structure pretwisting and local deflection of the blade, and setting output parameters as follows: the locally deforming blade, which evolves over time and space, couples the blade structure reaction load, including aerodynamic loads and inertial loads from structural dynamics. Once the fully coupled dynamic simulator is successfully run, these outputs are automatically transferred to a program interface, such as MATLAB or Python, to perform a series of coordinate transformation and load decomposition operations and subsequent dynamic mapping algorithms.
And 3, carrying out coordinate transformation and de-integration operation, converting a local blade coordinate system into a global blade coordinate system, and converting a reaction load into an equivalent concentrated external load, wherein the method specifically comprises the following steps of:
to facilitate subsequent loading on the three-dimensional high-fidelity blade finite element model, discrete reaction forces and reaction bending moments at different blade span sections in the local blade coordinate system are first converted from the local blade coordinate system to the blade coordinate system (constant along the blade span, independent of blade deflection and structural pretwist) specified in DNVGL-ST-0376, shown in FIG. 7. From a local blade coordinate system (x L ，y L ，z L ) The conversion to the global blade coordinate system (XB, YB, ZB) may be represented by the following equation:
wherein θ 1 And theta 2 Respectively representing the local roll and pitch deflection of a given blade section in radians; gamma denotes the structural pretwist angle in degrees.
Then, the reaction load R at each blade analysis node in the global blade coordinate system obtained after the coordinate transformation operation is subjected to a de-integration operation, and decomposed along the direction from the blade tip to the blade root, so as to obtain a concentrated equivalent external load L acting on a given blade analysis node i, and the blade analysis node closest to the blade tip is assumed to be i max Then:
notably, if the global blade coordinate system where the equivalent concentrated load is located is inconsistent with the global coordinate system of the established three-dimensional blade finite element model, the global blade coordinate system is further converted into the global coordinate system of the established three-dimensional high-fidelity blade finite element model, so that the global blade coordinate system is easy to load. For example, FIG. 8 shows a general Cartesian coordinate system of a three-dimensional high-fidelity blade finite element model constructed in accordance with the present invention, with the X-axis pointing from the trailing edge to the leading edge and parallel to the chord line of the zero twist blade station, the Z-axis pointing from the blade root to the blade tip along the pitch axis, and the Y-axis orthogonal to the X-axis and the Z-axis, thereby forming a right hand coordinate system. The conversion from the global blade coordinate system to the global cartesian coordinate system of the three-dimensional finite element model is thus as follows:
and 4, mapping concentrated loads acting on blade analysis nodes under a blade overall Cartesian coordinate system to a series of finite element nodes of a three-dimensional finite element model of the blade according to a reasonable method by a dynamic mapping algorithm at each time step, wherein the method specifically comprises the following steps:
as shown in figure 6 of the drawings,the dynamic mapping algorithm proposed in this embodiment dynamically maps the concentrated forces and moments on each given beam unit blade analysis node to a series of three-dimensional finite element model nodes within the corresponding blade segment between that node and the next node pointing to the blade tip at each time step, thereby maintaining the mechanical balance of the concentrated equivalent loads on each section. Specifically, for a given blade analysis node i of the beam unit model at a certain time step, assuming that the distance from the node i to the root of the blade along the pitch axis direction of the blade is r, the coordinate of the node is (X i ,Y i R) and the flapwise, edgewise forces acting on it during this time step are F respectively X,i ,F Y,i And M Z,i There are N nodes from i to the corresponding segment of the three-dimensional finite element model pointing to the next blade analysis node of the tip. For a coordinate of (X j ,Y j ,Z j ) Is given a node force f in the shimmy direction X,j And node force f in the flapwise direction Y,j Obeying a linear distribution in relation to its coordinates, whereas the axial node force f Z,j Average distribution (constant from 1 to N with j). The following mechanical equilibrium conditions can be established:
wherein X is 0 ＝X j -X i ，Y 0 ＝Y j -Y i ；k 1 To k 7 To obtain the unknown coefficients, they can be obtained from linear algebraic calculations. Notably, given the shape of the blade airfoil, it is assumed that only the flapwise forces (f Y,j ) For M Z,i Contributing, F X,i Is balanced and does not generate moment. In addition, for each blade analysis node i and each three-dimensional finite element model node j, the coordinates of which are time-varying, need to be updated accordingly at each time step.
And 5, carrying out quasi-static or transient analysis considering large deformation effect, namely geometrical nonlinearity by adopting a general finite element program, on one hand, obtaining a refined finite element analysis result of the blade in the time step, and on the other hand, feeding back the change of the three-dimensional blade geometry structure to a dynamic mapping algorithm to realize dynamic iteration solution, wherein the method specifically comprises the following steps:
in this embodiment, universal finite element software ANSYS is used to perform time domain refined finite element computational analysis, perform quasi-static analysis that takes large deformation effects into account on the established high-fidelity three-dimensional blade layered shell model, and act as a post-processor that can process simulation results in accordance with a series of ANSYS Mechanical APDL (ANSYS parameterized design language) commands. On the one hand, various types of refined finite element analysis such as time domain stress/strain distribution, buckling, fatigue and the like of the whole and partial components of the blade can be performed, and the time domain load of the blade structure and the material concerned is extracted, as shown in fig. 9, the von Mises stress distribution (unit: pa) of a certain blade at a certain moment in the time domain is shown. On the other hand, ANSYS automatically invokes the MATLAB interface program at each time step to communicate and feed back changes in three-dimensional blade geometry (finite element model node coordinate changes) relative to undeflected positions to the dynamic mapping algorithm to achieve dynamic iterative solution. In addition to ANSYS, other commercial finite element analysis codes, such as Abaqus, etc., may be used to perform the same task.
It should be noted that the invention is not limited to offshore wind power, and onshore wind power is also applicable; and the invention is not limited to wind power blades, other components of the wind turbine complete machine (such as blades, hubs, drive trains and towers) and the like are applicable to the same or similar methods as the invention.
The above-described embodiments are merely representative of the more specific and detailed embodiments described herein and are not to be construed as limiting the claims. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.
Claims (8)
1. A wind turbine blade full-coupling dynamic response refined analysis method is characterized by comprising the following steps:
step 1, carrying out integrated load simulation on various load working conditions by using a full-coupling dynamic simulator so as to obtain a blade structure dynamic response capable of coupling the dynamics of the whole wind turbine system;
step 2, enabling the full-coupling dynamic simulator to output time-varying displacement of a beam model blade analysis node in a local blade coordinate system and coupling structural dynamics reaction load comprising external aerodynamic load and inertial load;
step 3, carrying out coordinate transformation and de-integration operation, converting a local blade coordinate system into a global blade coordinate system, and converting a reaction load into an equivalent concentrated external load;
step 4, mapping concentrated loads acting on blade analysis nodes under the whole coordinate system of the blade to finite element nodes of the three-dimensional finite element model of the blade according to a reasonable method through a dynamic mapping algorithm at each time step;
and 5, performing quasi-static or transient analysis considering the large deformation effect on the high-fidelity blade finite element model by utilizing a general finite element program, so as to obtain a refined finite element analysis result of the blade at each time step, and feeding back the spatial position change of the three-dimensional blade geometry structure to the dynamic mapping algorithm in the step 4 at each time step to realize dynamic iteration solution of the time domain.
2. The method for refined analysis of full-coupling dynamic response of wind turbine blades according to claim 1, wherein in the step 1, after external environmental condition parameters and internal fan condition parameters are input, integrated solution capable of simultaneously considering aerodynamics, hydrodynamics, soil-structure interaction, structural dynamics and servo control dynamics is realized in a full-coupling dynamic simulator.
3. The method for refined analysis of full-coupling dynamic response of a wind turbine blade according to claim 1, wherein said step 2 comprises: setting an output coordinate system of the fully-coupled dynamic simulator requested in a time domain as a local blade coordinate system considering local structure pretwisting and local deflection of the blade, and setting output parameters as follows: the locally deforming blade, which evolves over time and space, couples the blade structure reaction load, including aerodynamic loads and inertial loads from structural dynamics.
4. The method for refined analysis of full-coupling dynamic response of a wind turbine blade according to claim 1, wherein said step 3 comprises: discrete reaction forces and reaction bending moments at different blade span sections in a local blade coordinate system are firstly converted from the local blade coordinate system to a global blade coordinate system specified in international standards, and then the local blade coordinate system (x L ，y L ，z L ) The conversion to the global blade coordinate system (XB, YB, ZB) may be represented by the following equation:
wherein θ 1 And theta 2 Respectively representing the local roll and pitch deflection of a given blade section in radians; gamma represents the structural pretwist angle in degrees;
then, the reaction load R at each blade analysis node in the global blade coordinate system obtained after the coordinate transformation operation is subjected to a de-integration operation, and decomposed along the direction from the blade tip to the blade root, so as to obtain a concentrated equivalent external load L acting on a given blade analysis node i, and the blade analysis node closest to the blade tip is assumed to be i max Then:
5. the method for refined analysis of full-coupling dynamic response of a wind turbine blade according to claim 4, wherein said step 3 further comprises: if the global blade coordinate system where the equivalent concentrated load is located is inconsistent with the global coordinate system of the established three-dimensional blade finite element model, the global blade coordinate system is further converted into the global coordinate system of the established three-dimensional high-fidelity blade finite element model, so that the loading is easy.
6. The method for refined analysis of full-coupling dynamic response of a wind turbine blade according to claim 1, wherein said step 4 comprises: the concentrated force and moment on each given beam unit blade analysis node is dynamically mapped to the three-dimensional finite element model node in the corresponding blade segment between the node and the next node pointing to the blade tip at each time step through the developed dynamic mapping algorithm, so that the mechanical balance of concentrated equivalent load on each section is maintained.
7. The method for refined analysis of full-coupling dynamic response of a wind turbine blade according to claim 6, wherein the step 4 specifically comprises: for a given blade analysis node i of the beam unit model at a certain time step, assuming that the distance from the node i to the blade root along the direction of the variable pitch axis of the blade is r, the coordinate of the node is (X i ,Y i R) and the flapwise, edgewise forces acting on it during this time step are F respectively X,i ,F Y,i And M Z,i The corresponding segment of the three-dimensional finite element model from i to the next blade analysis node pointing to the tip has N nodes, for a coordinate (X j ,Y j ,Z j ) Is given a node force f in the shimmy direction X,j And node force f in the flapwise direction Y,j Obeying a linear distribution in relation to its coordinates, whereas the axial node force f Z,j The average distribution can establish the following mechanical balance conditions:
wherein X is 0 ＝X j -X i ，Y 0 ＝Y j -Y i ；k 1 To k 7 To obtain the unknown coefficients, they can be obtained from linear algebraic calculations.
8. The method for refined analysis of full-coupling dynamic response of a wind turbine blade according to claim 1, wherein said step 5 comprises: the method adopts a general finite element program to conduct quasi-static or transient analysis considering large deformation effect, namely geometrical nonlinearity, on one hand, various fine finite element analyses including stress strain, fatigue, failure, buckling and fracture of the whole and partial components of the blade can be conducted, time domain response and evaluation indexes of the blade structure and the material concerned are extracted, on the other hand, the finite element program automatically calls an interface program at each time step, so that the spatial position change of the three-dimensional blade geometry relative to the undeflected position is transferred and fed back to a dynamic mapping algorithm, and the time domain dynamic iterative solution is realized.
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| CN117828784A (en) * | 2023-12-28 | 2024-04-05 | 浙江大学 | Method for determining limit performance response of long and flexible blade of large wind power generator |
| CN117973159A (en) * | 2024-04-01 | 2024-05-03 | 中交(天津)轨道交通投资建设有限公司 | Method and system for analyzing supporting stress characteristics of foundation pit precast pile |
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| CN117828784A (en) * | 2023-12-28 | 2024-04-05 | 浙江大学 | Method for determining limit performance response of long and flexible blade of large wind power generator |
| CN117973159A (en) * | 2024-04-01 | 2024-05-03 | 中交(天津)轨道交通投资建设有限公司 | Method and system for analyzing supporting stress characteristics of foundation pit precast pile |
| CN117973159B (en) * | 2024-04-01 | 2024-06-11 | 中交(天津)轨道交通投资建设有限公司 | Method and system for analyzing supporting stress characteristics of foundation pit precast pile |
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