Method for checking and evaluating strength of wind wheel locking structure of wind turbine generator

Abstract

The invention provides a method for checking the strength of a wind wheel locking structure of a wind turbine generator, which comprises the following steps of: constructing a three-dimensional model of the wind wheel locking structure, and constructing a finite element model for calculating the wind wheel locking structure according to the three-dimensional model; performing grid division on each part of the finite element model; respectively setting a contact type, a material attribute, a constraint condition and a boundary condition; and calculating by using finite element simulation analysis software to obtain a wind wheel locking structure strength checking result. A locking hole of the bearing seat is established, and the influence of deformation of the bearing seat and a main rack on a result and the influence of interaction of a locking pin and the locking hole of the bearing seat on the result are considered during calculation of strength checking; the influence that a connecting bolt can bear a large load at the joint is considered; setting full constraints at the bottom of the main frame when the constraint conditions are set; and the transmission path of the locking load is more accurate. The invention further provides a method for evaluating the strength checking calculation result of the wind wheel locking structure of the wind turbine generator.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine generator sets, and in particular to a method for checking and evaluating the strength of a wind turbine rotor locking structure. Background Art

[0002] In a wind turbine, the rotor locking structure is mainly used to lock the rotor during single-blade hoisting and unit maintenance to ensure the personal safety of the unit and operation and maintenance personnel. Therefore, the strength design of the rotor locking structure is a key point that needs attention.

[0003] In the prior art, the patent with publication number CN105022876A records a calculation method for checking the strength of a wind turbine rotor lock, which provides a method for building a finite element model of a wind turbine rotor locking structure, establishing a three-dimensional geometric model of a wind turbine locking plate 3, a locking shaft 1, a locking sleeve 2 and a main shaft 4 prosthesis and assembling them, wherein the locking shaft and the locking sleeve are assembled by interference fit. The model is imported into the finite element analysis software to establish a finite element model of the wind turbine rotor lock. The boundary conditions and contacts of each component of the model are set, and the extreme load conditions are applied to the model to solve the force conditions of the wind turbine rotor lock, thereby obtaining the stress magnitude and dangerous position of the wind turbine rotor lock. The calculated results are compared with the allowable value of the wind turbine rotor lock to check its strength. However, compared with the actual working conditions, the model established by the above technical solution does not consider the influence of the deformation of the main frame on the wind turbine rotor locking structure, nor does it consider the strength of the connecting bolts, so the calculation results are not accurate enough. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention proposes a method for checking and evaluating the strength of the wind turbine rotor locking structure, so as to solve the technical problem that the prior art does not consider the influence of the deformation of the main frame on the wind turbine rotor locking structure, nor does it consider the strength of the connecting bolts, and therefore the calculation structure of the strength verification of the wind turbine rotor lock is not accurate enough.

[0005] The technical solution adopted by the present invention is as follows:

[0006] In a first aspect, a method for checking the strength of a wind turbine rotor locking structure is provided, comprising the following steps:

[0007] Construct a three-dimensional model of the wind rotor locking structure, and build a finite element model for calculating the wind rotor locking structure based on the three-dimensional model;

[0008] Mesh the components of the finite element model;

[0009] For each component of the meshed finite element model, set the contact type, material properties, constraints and boundary conditions;

[0010] The strength verification results of the wind wheel locking structure are calculated using finite element simulation analysis software.

[0011] Furthermore, both the three-dimensional model and the finite element model include the following components: a locking plate, a locking pin, a bearing seat, a main shaft, a main frame and connecting bolts.

[0012] Furthermore, when meshing the various components of the finite element model, the meshes of the contact areas between the locking pin and the locking hole of the bearing seat, and between the locking pin and the locking hole of the locking plate need to be refined and the nodes need to be aligned; high-order units are required for the locking pin, the wind wheel locking plate and the bearing seat.

[0013] Furthermore, the contact type is set, including: setting the locking pin and the locking hole of the bearing seat, the locking pin and the locking hole of the locking plate, and the bearing seat and the main frame to standard contact; and setting the contact between the remaining components to binding contact.

[0014] Furthermore, material properties are set, and the material includes rational elastic-plastic material.

[0015] Furthermore, constraint conditions are set, including: coupling the hub center with the spindle end face through a rigid connection unit, and using the hub center as the loading point; setting full constraints on the bottom of the main frame, constraining the translation of the spindle in the X / Y / Z directions and the rotational freedom in the Y / Z directions, and releasing the rotational freedom in the X direction.

[0016] Furthermore, boundary conditions are set, including: a wind wheel locking load is applied to the rigid connection unit.

[0017] In the second aspect, a method for evaluating the calculation results of the strength verification of the wind turbine rotor locking structure is provided, which is used to evaluate the calculation results of the strength verification method of the wind turbine rotor locking structure described in the first aspect, including evaluating the strength verification calculation results of the bearing seat, locking pin, locking plate, and connecting bolts.

[0018] Furthermore, the strength check calculation results of the bearing seat, locking pin and locking plate are evaluated as follows:

[0019] a) If the materials of the bearing seat, locking pin and locking plate are set to rational elastic-plastic materials, the elastic modulus, Poisson's ratio and density of the materials of the main shaft, main frame and connecting bolts are set;

[0020] The wind wheel locking structure allows plastic deformation. Through simulation analysis using finite element simulation analysis software, the strain conditions of the bearing seat, locking plate and locking pin are obtained respectively;

[0021] If the strains of the three are all less than 1%, the evaluation result is that the strength verification calculation results of the wind rotor locking structure meet the design requirements;

[0022] b) If all materials are set as linear elastic materials, the maximum stress of the bearing seat, locking pin and locking plate is extracted, and the strain ε corresponding to the stress is calculated according to the following formula:

[0023]

[0024] In the above formula, σ von is Von Mises stress, E is the elastic modulus of the material, σ S is the yield strength of the material, γ M is the safety factor;

[0025] If the strains ε of the three are all less than 1%, the evaluation result is that the strength verification calculation results of the wind wheel locking structure meet the design requirements.

[0026] Furthermore, the strength check calculation results of the connecting bolts are evaluated as follows:

[0027] Extract the stress of the connecting bolts from the strength check calculation results, and judge whether the bolt strength meets the design requirements according to the strength calculation results of the connecting bolts; including:

[0028] a) If a hydraulic tensioner is used, the residual shear stress is not considered and the strength calculation formula of the connecting bolt is as follows:

[0029]

[0030] In the above formula, is the stress caused by the bolt axial force, F A is the bolt axial force, A s is the load-bearing cross-sectional area of ​​the bolt;

[0031] is the stress caused by the bolt bending moment, M b is the bolt bending moment, W b is the bending section coefficient of the bolt;

[0032] σ eqv is the equivalent stress of the bolt, σ p0.2 is the ultimate stress of the bolt, γ Ms is the safety factor;

[0033] b) If a hydraulic wrench is used, the residual shear stress needs to be considered and the strength calculation formula of the connecting bolt is as follows:

[0034]

[0035] In the above formula is the stress caused by the bolt axial force, F A is the bolt axial force, A s is the load-bearing cross-sectional area of ​​the bolt;

[0036] is the stress caused by the bolt bending moment, M b is the bolt bending moment, W b is the bending section coefficient of the bolt;

[0037] τ is the bolt shear stress, F M is the preload force, d2 is the thread diameter, P is the thread pitch, μ Gmin is the thread friction coefficient, W t is the torsional section coefficient,

[0038] σ eqv is the equivalent stress of the bolt, σ p0.2 is the ultimate stress of the bolt, γ Ms is the safety factor.

[0039] It can be seen from the above technical solution that the beneficial technical effects of the present invention are as follows:

[0040] 1. A strength verification method for the wind turbine rotor locking structure based on plastic strain is proposed. This method establishes the locking hole of the bearing seat. When performing strength verification calculations, the influence of the deformation of the bearing seat and the main frame on the results, as well as the influence of the interaction between the locking pin and the locking hole of the bearing seat on the results are considered; the influence of the connecting bolts being subjected to a large load at the connection point is considered; when setting the constraint conditions, the bottom of the main frame is set with full constraints; the transmission path of the locking load is made more accurate and more in line with the actual working conditions, so that the final calculated strength verification result of the wind rotor locking structure is more accurate.

[0041] 2. It is proposed to use plastic strain as the basis for judging the finite element strength check calculation results of the wind rotor locking structure, and a method for evaluating the strength check calculation results is given, which can verify whether the strength check calculation results of the wind rotor locking structure meet the design requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the prior art description. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0043] Figure 1 A three-dimensional model of the wind wheel locking structure of Example 1 of the present invention;

[0044] Figure 2 This is a partial screenshot of the finite element model of the wind wheel locking structure of Example 1 of the present invention;

[0045] Figure 3This is a schematic diagram of constraint conditions of the finite element model of the wind wheel locking structure of Example 1 of the present invention;

[0046] Figure 4 is the ideal elastic-plastic material curve of Example 2 of the present invention;

[0047] Figure 5 The strain condition of the bearing seat in Example 2 of the present invention;

[0048] Figure 6 The strain condition of the locking disk of Example 2 of the present invention;

[0049] Figure 7 The strain condition of the locking pin of Example 2 of the present invention;

[0050] Reference numerals:

[0051] 1-main shaft, 2-wind wheel locking plate, 3-bearing seat, 4-main frame, 5-locking pin, 6-connecting bolt. DETAILED DESCRIPTION

[0052] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0053] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0054] Example 1

[0055] The wind wheel locking structure can be divided into front-end low-speed shaft locking and gearbox high-speed shaft locking. The front-end low-speed shaft locking has the advantages of being safe, reliable and not prone to failure. Therefore, this embodiment mainly performs finite element strength verification and evaluation on the front-end low-speed shaft locking structure.

[0056] This embodiment provides a method for checking the strength of a wind turbine rotor locking structure based on plastic strain. The method proposes that when establishing a finite element model of the wind turbine rotor locking, the main shaft, locking plate, locking pin, bearing seat, and main frame structure need to be considered to ensure the accuracy of the finite element calculation of the wind turbine rotor locking structure. The method includes the following steps:

[0057] S1. Construct a three-dimensional model of the wind rotor locking structure, and build a finite element model for calculating the wind rotor locking structure based on the three-dimensional model.

[0058] The wind wheel locking structure and the three-dimensional model required for calculation, such as Figure 1As shown, the three-dimensional model includes the following components: a locking disk, a locking pin, a bearing seat, a main shaft, a main frame and connecting bolts. In a specific embodiment, the three-dimensional model can be constructed by any feasible method in the prior art, such as using three-dimensional modeling software.

[0059] The finite element model includes components corresponding to the three-dimensional model: a locking plate, a locking pin, a bearing seat, a main shaft, a main frame and connecting bolts. In a specific implementation, the finite element model can be constructed by any feasible method in the prior art, such as using finite element simulation analysis software.

[0060] S2. Mesh the components of the finite element model

[0061] In a specific implementation, finite element simulation analysis software is used to mesh the various components of the finite element model. In order to speed up the convergence speed of the finite element model calculation, the mesh of the contact area between the locking pin and the locking hole of the bearing seat, and the locking pin and the locking hole of the locking plate needs to be refined and the nodes need to be aligned, and the locking pin, the wind wheel locking plate and the bearing seat need to use high-order units, such as Figure 2 In this embodiment, refinement refers to refinement of the grid size.

[0062] S3. Set contact type, material properties, constraints and boundary conditions for each component of the finite element model

[0063] On the basis of meshing, the contact type, material properties, constraints and boundary conditions are set for each component of the finite element model, as follows:

[0064] S31. Setting the contact type, including:

[0065] In the finite element simulation analysis software, the locking pin and the locking hole of the bearing seat, the locking pin and the locking hole of the locking plate, and the bearing seat and the main frame are set to standard contact, and the friction coefficient is determined according to the design file; the contact between the remaining components (such as between the locking plate and the main shaft, etc.) is set to binding contact.

[0066] S32. In the finite element simulation analysis software, material properties are assigned to each component. In a specific implementation, the material of each component can be selected from the general material of the component in the prior art, such as rational elastic-plastic material, and ductile iron QT400 is selected, which has a yield strength of 220 MPa.

[0067] S33. In the finite element simulation analysis software, the hub center is coupled to the spindle end face through a rigid connection unit, and the hub center is used as the loading point, such as Figure 3 As shown, the bottom of the main frame is fully constrained. In this embodiment, the rigid connection unit is used to simulate the rigid constraint between two deformable bodies or as a rigid component for transmitting force and moment.

[0068] Constrain the translation of the spindle in the X / Y / Z directions and the rotational freedom in the Y / Z directions, and release the rotational freedom in the X direction.

[0069] S34, applying boundary conditions, applying the wind wheel locking load to the rigid connection unit set in step S33.

[0070] S4. Calculate the strength verification result of the wind wheel locking structure

[0071] According to the settings of step S3, the calculation is submitted in the finite element simulation analysis software to obtain the strength verification result of the wind wheel locking structure.

[0072] The technical solution of this embodiment proposes a strength verification method for the wind turbine rotor locking structure based on plastic strain. The method establishes a locking hole of the bearing seat, and takes into account the influence of the deformation of the bearing seat and the main frame on the result, as well as the influence of the interaction between the locking pin and the locking hole of the bearing seat on the result when performing strength verification calculation; takes into account the influence of the connecting bolts being subjected to a large load at the connection point; sets full constraints on the bottom of the main frame when setting constraints; makes the transmission path of the locking load more accurate and more in line with actual working conditions, so that the final calculated strength verification result of the wind turbine rotor locking structure is more accurate.

[0073] Example 2

[0074] The prior art only provides a strength verification calculation method for the wind rotor locking structure, but does not provide an evaluation method for the calculation result. This embodiment, based on Embodiment 1, provides an evaluation method for the strength verification calculation result of the wind rotor locking structure of a wind turbine generator set, including evaluating the strength verification calculation results of the bearing seat, the locking pin, the locking plate, and the connecting bolts, as follows:

[0075] 1. Evaluate the strength verification calculation results of the bearing seat, locking pin and locking plate

[0076] a) In the first case, if the materials of the bearing seat, locking pin and locking plate are set to ideal elastic-plastic materials, the ideal elastic-plastic material curve is as follows: Figure 4 As shown; at the same time, the elastic modulus, Poisson's ratio and density of the materials of the remaining components (spindle, main frame and connecting bolts) are set.

[0077] The wind wheel locking structure allows plastic deformation, and the following results are obtained through simulation analysis using finite element simulation software:

[0078] The strain of the bearing seat is as follows: Figure 5 As shown in Figure 2, the strain of the locking disk is as follows: Figure 6 As shown in Figure 2, the strain of the locking pin is as follows: Figure 7As shown, if the strain conditions of the three are all less than 1%, the evaluation result is: the strength verification calculation results of the wind wheel locking structure meet the design requirements.

[0079] b) In the second case, if all materials are set as linear elastic materials, the maximum stress of the bearing seat, locking pin and locking plate is extracted, and the strain ε corresponding to the stress is calculated according to the following formula (1):

[0080]

[0081] In the above formula, σ von is Von Mises stress, E is the elastic modulus of the material, σ S is the yield strength of the material, γ M is the safety factor. If the strains ε of the three are all less than 1%, the evaluation result is: the strength verification calculation results of the wind wheel locking structure meet the design requirements.

[0082] 2. Evaluate the strength check calculation results of the connecting bolts

[0083] Extract the stress of the connecting bolts from the strength check calculation results, and judge whether the bolt strength meets the design requirements according to the strength calculation results of the connecting bolts, as follows:

[0084] a) If a hydraulic tensioner is used, the residual shear stress is not considered and the strength calculation formula of the connecting bolt is as follows:

[0085]

[0086] In the above formula, is the stress caused by the bolt axial force, F A is the bolt axial force, A s is the load-bearing cross-sectional area of ​​the bolt;

[0087] is the stress caused by the bolt bending moment, M b is the bolt bending moment, W b is the bending section coefficient of the bolt;

[0088] σ eqv is the equivalent stress of the bolt, σ p0.2 is the ultimate stress of the bolt, γ Ms is the safety factor, generally taken as 1.

[0089] b) If a hydraulic wrench is used, the residual shear stress needs to be considered and the strength calculation formula of the connecting bolt is as follows:

[0090]

[0091] In the above formula is the stress caused by the bolt axial force, FA is the bolt axial force, A s is the load-bearing cross-sectional area of ​​the bolt;

[0092] is the stress caused by the bolt bending moment, M b is the bolt bending moment, W b is the bending section coefficient of the bolt;

[0093] τ is the bolt shear stress, F M is the preload force, d2 is the thread diameter, P is the thread pitch, μ Gmin is the thread friction coefficient, W t is the torsional section coefficient,

[0094] σ eqv is the equivalent stress of the bolt, σ p0.2 is the ultimate stress of the bolt, γ Ms is the safety factor, generally taken as 1.

[0095] Through the technical solution of this embodiment, it is proposed to use plastic strain as the basis for judging the finite element strength verification calculation results of the wind wheel locking structure, and a method for evaluating the strength verification calculation results is provided, which can verify whether the strength verification calculation results of the wind wheel locking structure meet the design requirements.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A method for checking the strength of a wind turbine rotor locking structure, characterized in that: The following steps are involved: Construct a three-dimensional model of the wind rotor locking structure, and build a finite element model for calculating the wind rotor locking structure based on the three-dimensional model; Mesh the components of the finite element model; For each component of the meshed finite element model, set the contact type, material properties, constraints and boundary conditions; The strength verification results of the wind wheel locking structure are calculated using finite element simulation analysis software.

2. The method for checking the strength of the wind turbine rotor locking structure according to claim 1 is characterized in that: The three-dimensional model and the finite element model both include the following components: a locking disk, a locking pin, a bearing seat, a main shaft, a main frame and connecting bolts.

3. The method for checking the strength of the wind turbine rotor locking structure according to claim 1, characterized in that: When meshing the various components of the finite element model, the meshes in the contact area between the locking pin and the locking hole of the bearing seat, and between the locking pin and the locking hole of the locking plate need to be refined and the nodes need to be aligned; high-order units are required for the locking pin, the wind wheel locking plate and the bearing seat.

4. The method for checking the strength of the wind turbine rotor locking structure according to claim 1, characterized in that: Set the contact type, including: setting the locking pin and the locking hole of the bearing seat, the locking pin and the locking hole of the locking plate, and the bearing seat and the main frame as standard contact; setting the contact between the remaining parts as binding contact.

5. The method for checking the strength of the wind turbine rotor locking structure according to claim 1, characterized in that: Set material properties, including rational elastic-plastic materials.

6. The method for checking the strength of the wind turbine rotor locking structure according to claim 1, characterized in that: Set constraint conditions, including: coupling the hub center with the spindle end face through a rigid connection unit, and using the hub center as the loading point; setting full constraints on the bottom of the main frame, constraining the translation of the spindle in the X / Y / Z directions and the rotational freedom in the Y / Z directions, and releasing the rotational freedom in the X direction.

7. The method for checking the strength of the wind turbine rotor locking structure according to claim 1, characterized in that: Boundary conditions are set, including: the wind wheel locking load is applied to the rigid connection unit.

8. A method for evaluating calculation results of strength verification of a wind turbine rotor locking structure, used for evaluating the calculation results of the method for strength verification of a wind turbine rotor locking structure according to any one of claims 1 to 7, characterized in that: This includes evaluating the strength verification calculation results of the bearing seat, locking pin, locking plate, and connecting bolts.

9. The method for evaluating the calculation results of the strength verification of the wind turbine rotor locking structure according to claim 8, characterized in that: The strength check calculation results of the bearing seat, locking pin and locking plate are evaluated as follows: a) If the materials of the bearing seat, locking pin and locking plate are set to rational elastic-plastic materials, the elastic modulus, Poisson's ratio and density of the materials of the main shaft, main frame and connecting bolts are set; The wind wheel locking structure allows plastic deformation. Through simulation analysis using finite element simulation analysis software, the strain conditions of the bearing seat, locking plate and locking pin are obtained respectively; If the strains of the three are all less than 1%, the evaluation result is that the strength verification calculation results of the wind rotor locking structure meet the design requirements; b) If all materials are set as linear elastic materials, the maximum stress of the bearing seat, locking pin and locking plate is extracted, and the strain ε corresponding to the stress is calculated according to the following formula: In the above formula, σ von is Von Mises stress, E is the elastic modulus of the material, σ S is the yield strength of the material, γ M is the safety factor; If the strains ε of the three are all less than 1%, the evaluation result is that the strength verification calculation results of the wind wheel locking structure meet the design requirements.

10. The method for evaluating the calculation results of the strength verification of the wind turbine rotor locking structure according to claim 8, characterized in that: The strength check calculation results of the connecting bolts are evaluated as follows: Extract the stress of the connecting bolts from the strength check calculation results, and judge whether the bolt strength meets the design requirements according to the strength calculation results of the connecting bolts; including: a) If a hydraulic tensioner is used, the residual shear stress is not considered and the strength calculation formula of the connecting bolt is as follows: In the above formula, is the stress caused by the bolt axial force, F A is the bolt axial force, A s is the load-bearing cross-sectional area of ​​the bolt; is the stress caused by the bolt bending moment, M b is the bolt bending moment, W b is the bending section coefficient of the bolt; σ eqv is the equivalent stress of the bolt, σ p0.2 is the ultimate stress of the bolt, γ Ms is the safety factor; b) If a hydraulic wrench is used, the residual shear stress needs to be considered and the strength calculation formula of the connecting bolt is as follows: In the above formula, σ Z F is the stress caused by the bolt axial force, F A is the bolt axial force, A s is the load-bearing cross-sectional area of ​​the bolt; σ Z M is the stress caused by the bolt bending moment, M b is the bolt bending moment, W b is the bending section coefficient of the bolt; τ is the bolt shear stress, F M is the preload force, d2 is the thread diameter, P is the thread pitch, μ Gmin is the thread friction coefficient, W t is the torsional section coefficient, σ eqv is the equivalent stress of the bolt, σ p0.2 is the ultimate stress of the bolt, γ Ms is the safety factor.

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