CN-122021171-A - Analysis and calculation method, equipment and medium for blade root connection structure of wind driven generator

CN122021171ACN 122021171 ACN122021171 ACN 122021171ACN-122021171-A

Abstract

The invention relates to an analysis and calculation method of a blade root connection structure of a wind driven generator, which comprises the steps of constructing a finite element model of coupling of a blade shell unit and a blade root entity unit, and defining material properties of all parts; and further, the coupling connection relation between the blade shell unit and the blade root entity unit is set so as to simulate a real force transmission path. And then, firstly applying and locking target pretightening force to the connecting bolt, and then applying distributed working load to the blade shell unit at different angles under the pretightening state, so that the bending moment of the blade root end is larger than the limit load under the angle. And solving and calculating the loaded model, extracting stress data of the connecting bolt and the bolt sleeve, and executing strength and fatigue analysis of the bolt and the bolt sleeve based on the data. According to the method, the accuracy and the model precision of stress calculation of the blade root connecting structure are remarkably improved by introducing the geometric characteristics, the rigidity characteristics and the distributed load transmission paths of the real blade, so that more reliable guidance is provided for the design of the root and the connecting structure of the wind power blade.

Inventors

FENG XUEBIN
JIANG DONG
ZHAO JIANGANG
WU FANGHE
LI YUAN
ZHOU PING
Ben Yingfeng
ZHANG WENWEI
DENG HANG
LEI ZHIMIN
LIU PENGHUI
XIAO QIONG
CHEN NANA
Qu Zhuohang
YOU HAOLIN

Assignees

株洲时代新材料科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260204

Claims (10)

1. The analysis and calculation method of the blade root connection structure of the wind driven generator is characterized by comprising the following steps of: Constructing an integrated finite element model comprising a blade shell unit model and a blade root connection structure entity unit model; Defining material properties of the blade shell unit model and the blade root connection structure entity unit model based on the constructed integrated finite element model; setting a coupling connection relation between the blade shell unit model and the blade root connection structure entity unit model in the integrated finite element model based on the defined material properties; applying a target pretightening force to a connecting bolt in the integrated finite element model through the set coupling connection relation; under the condition of keeping the state of the pre-tightening force applied, applying distributed working load to the blade shell unit model through the coupling connection relation; Solving and calculating the integrated finite element model loaded with the distributed workload, and extracting stress data of a connecting bolt in a blade root connecting structure; And carrying out strength analysis and fatigue analysis of the connecting bolts based on the extracted stress data of each connecting bolt.
2. The method for analyzing and calculating a blade root connection structure of a wind turbine according to claim 1, wherein the method for constructing an integrated finite element model including a blade shell element model and a blade root connection structure entity element model comprises: according to the actual layering design of the blade, a shell unit is adopted to establish a finite element model of the blade; Modeling the embedded blade root, the blade root flange, the bolt sleeve and the hub by adopting a solid unit according to the actual geometric structure of the blade root connection structure; Modeling the connecting bolts by adopting beam units according to the actual stress and connection relation of the blade root connecting structure, and modeling the rollers of the pitch bearing by adopting axial connecting units; And assembling the blade shell unit model, the beam unit model of the connecting bolt, the axial connecting unit model of the pitch bearing and the entity unit model of the embedded blade root, the blade root flange, the bolt sleeve and the hub to form the integrated finite element model.
3. The analytical calculation method for the blade root connection structure of the wind driven generator according to claim 2, wherein the connecting bolts are modeled by using Timoshenko beam units B32, and the rollers of the pitch bearing are modeled by using Axial connecting units.
4. The method of analytical calculation of a wind turbine blade root connection structure according to claim 1, wherein the method of applying a distributed workload to the blade shell element model comprises: According to the actual load working condition and the distribution of the blade load nodes, calculating a corresponding concentrated force load; and applying the concentrated force load to a corresponding node or surface of the blade shell unit model so that an equivalent bending moment generated by the concentrated force load meets the calculation requirement.
5. The method of analytical calculation of a wind turbine blade root connection structure according to claim 1, further comprising the step of defining a blade root coordinate system prior to applying a distributed workload to the blade shell element model, wherein: the XB shaft is in the axial direction of the wind wheel, points to the suction surface from the pressure surface and is perpendicular to the zero torsion curve; the ZB shafts are distributed along the spanwise direction of the blade; The YB shaft is perpendicular to the axis of the wind wheel, points from the front edge to the rear edge and is parallel to the zero torsion curve; the distributed working load is decomposed into six components under the blade root coordinate system for application.
6. The method for analyzing and calculating a blade root connection structure of a wind turbine according to claim 1, wherein the method for performing fatigue analysis of the connection bolts comprises: according to the extracted stress data of each connecting bolt under different angle loads, establishing a bending moment-stress relation under unit load; Processing the load time history by adopting a rain flow counting method to obtain stress amplitude, mean value and cycle number required by fatigue calculation, and forming the load Markov matrix; And calculating the total damage value of each connecting bolt according to the bending moment-stress relation, the load Markov matrix and the fatigue SN curve of the bolt material and the linear accumulated damage theory.
7. The method for analyzing and calculating a blade root connection structure of a wind turbine according to claim 1, wherein the method for analyzing the strength of the connection bolt comprises: Extracting envelope stress of each connecting bolt under limit load; and comparing the envelope stress with the bolt yield stress specified by the standard to judge whether the bolt strength meets the requirement.
8. The method of analyzing and calculating a root connection structure of a wind turbine according to claim 7, further comprising performing a fatigue analysis of a root bolt sleeve, the fatigue analysis comprising: Obtaining a unit load bending moment-drawing force relation of the bolt sleeve under each angle load according to the solving and calculating result; According to the load Markov matrix, calculating the fatigue drawing force value of the equivalent set cycle number of each bolt sleeve according to the linear accumulated damage theory; And comparing the calculated fatigue drawing force value with an experimentally obtained allowable value of the fatigue drawing force of the bolt sleeve to judge whether the fatigue performance of the bolt sleeve meets the requirement.
9. An electronic device comprising a memory and a processor, wherein the memory is configured to store a program for supporting the processor to perform the method of analyzing and calculating the root connection structure of the wind turbine blade according to any one of claims 1-8, the processor being configured to execute the program stored in the memory.
10. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, performs the steps of the method for analysing and calculating a blade root connection structure of a wind turbine according to any one of claims 1-8.

Description

Analysis and calculation method, equipment and medium for blade root connection structure of wind driven generator Technical Field The invention relates to the technical field of wind power generation, in particular to an analysis and calculation method, equipment and medium for a blade root connection structure of a wind power generator. Background The blade root connecting structure of the wind driven generator is responsible for reliably connecting the large composite material blade with the hub, and the strength and fatigue performance of the bolt of the blade root connecting structure are directly related to the operation safety and service life of the whole wind driven generator. Therefore, in the blade design stage, it is important to perform high-fidelity mechanical analysis on the blade root connection structure. Currently, conventional analytical calculation methods in this field are mainly based on two types of simplified strategies to cope with the huge calculation amount brought by full-size blade models containing a large number of composite material layers. The first type of simplification consists in model simplification. Only a refined entity finite element model containing key components such as a blade root flange, a pre-buried bolt sleeve, a connecting bolt and the like is usually established, and a blade main body with a complex upper structure and a huge size is completely omitted. For example, the patent with publication number CN201810495918.6 discloses a fatigue strength evaluation method for a blade connecting bolt, which is characterized in that the intelligent evaluation of the bolt is performed, and the patent with publication number CN202510043317.1 is focused on a fatigue strength analysis flow of a blade root bolt, so that the method effectively improves the calculation efficiency and the convergence by greatly reducing the model scale. The second type of simplification consists in load simplification. The complex distributed aerodynamic load, gravity, inertial force and the like borne by the blade in actual operation are equivalently simplified into a concentrated force and a concentrated bending moment (namely 'blade root equivalent load') acting on the center of the blade root bolt ring, and the concentrated force and the concentrated bending moment are directly applied to the simplified blade root model. However, the above simplified method introduces errors that are difficult to ignore, resulting in deviations of the analysis results from the true stress state, mainly in the following aspects: 1. The real composite material blade is not a rigid body, the rigidity of the real composite material blade is asymmetrically distributed in space, the real composite material blade is mainly dominated by structures such as front and rear edge girders, webs and the like, and the rigidity characteristics of the waving direction and the shimmy direction are different. The simplified model completely ignores the spatial rigidity characteristic of the blade main body, so that the boundary condition of the blade root connecting structure is inconsistent with the actual condition, and the influence of the integral deformation of the blade on the stress of the bolt cannot be reflected. 2. In actual operation, loads are gradually transferred to the blade root through structures such as blade skins, girders and the like. The distributed load is forcedly equivalent to the concentrated load at the blade root, so that the real path and local effect of load transmission are covered. This simplification may lead to distortion of the load distribution ratio calculation at the root connection interface, particularly between bolts. 3. And an equivalent concentrated load is applied to the simplified symmetrical model, so that the complex coupling effect generated by the asymmetrical blade structure when loaded cannot be reduced. For example, flapping bending moments and edgewise bending moments create different load distribution patterns for the bolts in an asymmetric blade, and a symmetric model and concentrated load cannot accurately simulate this physical process. In summary, although the prior art improves the calculation efficiency, the simulation accuracy of the blade root connection structure, particularly the load state of each bolt, is limited due to the failure to consider the actual structural characteristics of the blade and the influence of the blade on the load transmission. This directly affects the reliability of the subsequent fatigue life predictions, making it difficult to meet the design requirements of high reliability fan blades. Therefore, an analytical calculation method capable of reflecting the coupling stress state of the blade and the blade root more truly is needed. Disclosure of Invention The invention provides an analysis and calculation method, equipment and medium for a blade root connection structure of a wind driven generator, and aims to solve the problems of mech