Wind turbine blade root structure and wind turbine blade

Abstract

This application relates to the field of wind turbine blades, and discloses a root structure and a wind turbine blade. The root structure includes a root skin structure and a connecting assembly. The root skin structure includes a first skin layer and a second skin layer arranged radially, with a cavity formed between the first and second skin layers. The connecting assembly is connected to the cavity and includes multiple bolt sleeves, multiple extension sections, multiple fillers, and a reinforcing structure. The bolt sleeves are spaced circumferentially along the root skin structure. Extension sections are connected to one end of each bolt sleeve along its length. A filler is placed between adjacent bolt sleeves, supporting the first and second skin layers. The filler is bonded to the bolt sleeve and the extension section with a reinforcing structure. The equivalent elastic modulus of the reinforcing structure is greater than that of the extension section and less than that of the bolt sleeve. This improves the reliability of the wind turbine root.

Description

Technical Field

[0001] This application belongs to the field of wind turbine blades, and particularly relates to a root structure of a wind turbine blade and a wind turbine blade. Background Technology

[0002] Wind turbine blades have an aerodynamic shape and are able to receive and capture wind energy, making them an important component for energy production. The blade root is the part of the wind turbine that connects the blades and the hub, and it can be either a pre-embedded structure or a drilled structure.

[0003] In this type of blade root, a bolt sleeve is pre-embedded inside. The bolt sleeve is used to connect to the main engine pitch bearing via bolts, and then to the main engine hub via the pitch bearing. However, the current pre-embedded blade root has the problem of insufficient connection strength, which affects the reliability of the blade root. Summary of the Invention

[0004] This application provides a wind turbine blade root structure and a wind turbine blade, which can improve the reliability of the blade root.

[0005] On one hand, this application provides a root structure for a wind turbine blade, including: a root skin structure and a connecting assembly. The root skin structure includes a first skin layer and a second skin layer arranged radially, with a receiving cavity formed between the first skin layer and the second skin layer. The connecting assembly is connected to the receiving cavity and includes multiple bolt sleeves, multiple extension sections, multiple fillers, and a reinforcing structure. The multiple bolt sleeves are spaced apart circumferentially along the root skin structure. The extension sections are connected to one end of the bolt sleeves along their length direction. A filler is provided between two adjacent bolt sleeves. The filler is supported between the first skin layer and the second skin layer. The filler is bonded to the bolt sleeve and the extension section respectively with a reinforcing structure. The equivalent elastic modulus of the reinforcing structure is greater than the equivalent elastic modulus of the extension section and less than the equivalent elastic modulus of the bolt sleeve.

[0006] In some embodiments, the bolt sleeve is engaged with the extension section.

[0007] In some embodiments, the reinforcing structure includes a porous layer and a matrix, with at least a portion of the matrix bonded to the pores of the porous layer.

[0008] In some embodiments, the porous layer includes a braided layer.

[0009] In some embodiments, the porous layer includes a first portion, a second portion, and a third portion extending along its own length direction. The first portion and the second portion are continuously disposed. The first portion is bonded to the blade root skin structure and the bolt sleeve and to the blade root skin structure and the extension section. The second portion is bonded to the blade root skin structure and the filler. The third portion is bonded to the bolt sleeve and the filler and to the extension section and the filler.

[0010] In some embodiments, the first part, the second part, and the third part are arranged consecutively.

[0011] In some embodiments, a first portion is bonded between the first skin layer and the bolt sleeve and between the first skin layer and the extension section, and a second portion is bonded between the second skin layer and the filler.

[0012] In some embodiments, the first skin layer is an inner skin layer and the second skin layer is an outer skin layer.

[0013] In some embodiments, the porous layer continuously covers all bolt sleeves, all extension joints, and all fillers.

[0014] In some embodiments, a porous layer surrounds the periphery of the bolt sleeve and the extension joint.

[0015] In some embodiments, the filler is provided with a groove along the circumference of the leaf root, the groove being recessed from the bolt sleeve toward the center of the filler; the porous layer is accommodated in the groove, and the bolt sleeve is accommodated in the groove.

[0016] In some embodiments, the connecting assembly further includes a protrusion disposed between the bolt sleeve and the filler, and connected to the porous layer.

[0017] In some embodiments, the filler is provided with a groove along the circumference of the leaf root, the groove being recessed towards the center of the filler by a bolt sleeve; a protrusion is provided on the wall surface of the groove.

[0018] On the other hand, some embodiments of this application also provide a wind turbine blade, including the blade root structure of the wind turbine blade described above.

[0019] The wind turbine blade root structure and wind turbine blade of this application embodiment have a reinforcing structure provided between the bolt sleeve, the extension section and the filler. The equivalent elastic modulus of the reinforcing structure is between the equivalent elastic modulus of the bolt sleeve and the equivalent elastic modulus of the extension section, thereby forming a gradual change in the equivalent elastic modulus. The filler is bonded to the bolt sleeve and the extension section respectively with the reinforcing structure to form a structural interlock, improve the interface connection strength, disperse stress, thereby improve the connection stability and improve the overall strength of the blade root. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the end face of the leaf root in some embodiments of this application; Figure 2 Show Figure 1 A magnified view of a portion of the Q region; Figure 3 Show Figure 1 A cross-sectional view along the Z-axis of one example; Figure 4 A partial schematic diagram of the unfolded state of a connecting assembly of an example of the blade root structure of a wind turbine blade according to some embodiments of this application; Figure 5 A partial schematic diagram of the unfolded state of an example of the blade root structure of a wind turbine blade according to some embodiments of this application is shown. Figure 6 A partial schematic diagram of the unfolded state of another example of the blade root structure of a wind turbine blade according to some embodiments of this application; Figure 7 A partial schematic diagram of the unfolded state of the connecting assembly of another example of the blade root structure of a wind turbine blade according to some embodiments of this application is shown.

[0022] Explanation of reference numerals in the attached figures: 100. Leaf root skin structure; 110. First skin layer; 120. Second skin layer; 200. Connecting assembly; 210. Bolt sleeve; 220. Extension joint; 230. Filler; 231. Groove; 240. Reinforcing structure; 241. Porous layer; 241a. First part; 241b. Second part; 241c. Third part; 242. Matrix; V, circumferential direction; X, axial direction. Detailed Implementation

[0023] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0024] 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 pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0025] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0026] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0027] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0028] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0029] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0030] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0031] Wind turbine blades are manufactured using various processes, including mold bonding and integral injection molding. Internally, they consist of components such as the main beam, web, and skin. The main materials include glass / carbon fiber, structural adhesive, matrix resin, core material, and protective coating. Since the blade root is bolted, it includes pre-embedded bolt sleeves, UD filler, and core material filler rods. These pre-embedded components are designed with appropriate dimensions and tolerances, and are positioned, installed, and manufactured using positioning fixtures.

[0032] Large wind turbine blades have reached lengths exceeding 100 meters, and the reliability of the blade root connection is crucial to the operational safety of these blades. In existing pre-embedded blade roots, the bolt sleeves, extension sections, and fillers are in multiphase heterogeneous interface contact, and the strength of these different interfaces affects the overall strength of the blade root. During stress on the blade root, delamination and cracking can occur at the connection interfaces between the bolt sleeves, extension sections, and fillers. Specifically, in existing pre-embedded blade roots, the elastic modulus, coefficient of thermal expansion, and mechanical properties of the different materials used in the bolt sleeves, extension sections, and fillers vary significantly, resulting in interface strengths far lower than the strength of the individual materials themselves, thus becoming inherent weak points in the blade root structure.

[0033] As wind turbine blades grow to be larger, reaching lengths of 100 meters and above, the flapping moment, swaying moment, torque, and shear force borne by the blade root increase non-linearly and rapidly. Furthermore, throughout their entire lifespan, they must continuously withstand complex alternating loads, including wind loads, gravity loads, centrifugal loads, and impact loads under extreme conditions. Under the repeated cycles of these loads, stress concentration and microcracks easily occur at the connection interfaces of the bolt sleeves, extension sections, and fillers. These microcracks continuously expand and extend with each load cycle, eventually leading to irreversible damage such as interface delamination and matrix fracture. This damage causes a sharp decline in the interface's load-bearing capacity, inducing bolt sleeve loosening, displacement, or even pull-out, directly compromising the integrity of the blade root bolt connection. Ultimately, this results in blade root connection failure, causing major safety accidents such as blade detachment, and incurring high unit operation and maintenance costs and prolonged power generation losses, severely restricting the safe, reliable, and long-term operation of large wind turbine blades.

[0034] In view of this, the present application provides a blade root structure for a wind turbine blade, in which a reinforcing structure is provided between the bolt sleeve, the extension section, and the filler. The equivalent elastic modulus of the reinforcing structure is between that of the bolt sleeve and the extension section, thereby forming a gradual change in the equivalent elastic modulus. This reduces the difference in elastic modulus between adjacent materials, allowing stress to be gradually transferred and dispersed among the bolt sleeve, filler, and extension section, significantly reducing the stress concentration at each interface. Furthermore, the reinforcing structure forms a structural interlock with the bolt sleeve, extension section, and filler. The bonding strength of the reinforcing structure is higher than that of the thin-layer resin bonding between the bolt sleeve and the filler, and between the extension section and the filler in the prior art. Thus, based on the connection of multiphase heterogeneous interfaces, the interface connection strength is improved, stress is dispersed, thereby improving connection stability, increasing the overall strength of the blade root, and reducing the risk of failure.

[0035] The embodiments of this application are described below with reference to the accompanying drawings.

[0036] like Figures 1 to 3 As shown in some embodiments of this application, a wind turbine blade root structure includes a root skin structure 100 and a connecting assembly 200. The root skin structure 100 includes a first skin layer 110 and a second skin layer 120 arranged radially thereon, with a receiving cavity formed between the first skin layer 110 and the second skin layer 120. The connecting assembly 200 is connected to the receiving cavity and includes a plurality of bolt sleeves 210, a plurality of extension sections 220, and a plurality of fillers 230. The plurality of bolt sleeves 210 are spaced apart in a circumferential direction V along the root skin structure 100. The extension section 220 is connected to one end of the bolt sleeve 210 along its own length direction. A filler 230 is provided between two adjacent bolt sleeves 210. The filler 230 is supported between the first skin layer 110 and the second skin layer 120. The filler 230 is bonded to the bolt sleeve 210 and the extension section 220 respectively.

[0037] The leaf root structure can be a ring-shaped whole leaf root or an arc-shaped leaf root preform, with multiple leaf root preforms forming the whole leaf root.

[0038] The leaf root skin structure 100 refers to the inner and outer protective structures that constitute the leaf root structure, and can be arc-shaped or annular. As an example, when the leaf root structure is the entire leaf root, the leaf root skin structure 100 is arranged in an annular shape and is used to form a receiving cavity, and has a first skin layer 110 and a second skin layer 120 arranged radially thereafter. Exemplarily, the shape of the leaf root skin structure 100 can be circular, elliptical, or polygonal annular.

[0039] In some examples, the leaf root skin structure 100 can be set as an integral ring structure, or it can be formed by splicing multiple arc segments to form a complete ring.

[0040] The first skin layer 110 is one of the skin layers disposed radially inside or outside the leaf root skin structure 100, and the second skin layer 120 is another skin layer disposed opposite to the first skin layer 110, forming a receiving cavity between the two for accommodating the connecting assembly 200.

[0041] For example, the first skin layer 110 and the second skin layer 120 may be made of the same or different materials. For instance, the first skin layer 110 and the second skin layer 120 may be made of fiberglass cloth, carbon fiber cloth and resin composite. The first skin layer 110 may be located on the inner side and the second skin layer 120 on the outer side, or vice versa.

[0042] The receiving cavity extends continuously along the circumferential direction V of the blade root skin structure 100. Exemplarily, the first skin layer 110 and the second skin layer 120 have openings for the receiving cavity on the side opposite to the blade tip, and are stacked and contacted on the side closer to the blade tip. As an example, the distance between the first skin layer 110 and the second skin layer 120 from the opening towards the blade tip has a gradually decreasing trend.

[0043] The connecting assembly 200 refers to the assembly connected inside the receiving cavity to connect the blade root with other components and enhance the structural strength of the blade root, including multiple bolt sleeves 210, multiple fillers 230 and reinforcing structure 240.

[0044] Bolt sleeves 210 are components in the connecting assembly 200 used to insert bolts and achieve blade root connection and fixation. Multiple bolt sleeves 210 are arranged at intervals along the circumferential direction V of the blade root skin structure 100. For example, the bolt sleeves 210 may be cylindrical, square, stepped cylindrical, etc.

[0045] In some examples, the bolt sleeve 210 can be set to 8, 12, 16, etc., depending on the blade root size and stress requirements.

[0046] In some examples, the bolt sleeves 210 are evenly or non-uniformly distributed along the circumferential V of the blade root skin structure 100, and the axis of the bolt sleeves 210 may be perpendicular to the radial direction of the blade root skin structure 100 or at a preset angle.

[0047] In some examples, the bolt sleeve 210 may be made of high-strength steel, aluminum alloy, titanium alloy, etc.

[0048] The extension joint 220 is a component connected to one end of the bolt sleeve 210 body along its own length direction, used to extend the length of the bolt sleeve 210 to adapt to the installation requirements of the blade root. For example, the extension joint 220 may be wedge-shaped.

[0049] As an example, the extension section 220 can be a wedge-shaped structure formed by cutting off part of the material along some lengths, such as a cylindrical or prismatic structure, to accommodate the gradually transitioning thickness of the leaf root.

[0050] The number of extension sections 220 is the same as the number of bolt sleeves 210, with each bolt sleeve 210 corresponding to one extension section 220; the extension section 220 is connected to one end of the main body of the bolt sleeve 210. For example, the extension section 220 can be arranged coaxially with the main body of the bolt sleeve 210, or it can be arranged at a preset angle.

[0051] In some examples, the material of extension section 220 can be the same as that of bolt sleeve 210, such as high-strength steel or aluminum alloy, or it can be a high-strength composite material or foam that is different from the main material of bolt sleeve 210.

[0052] Extension joint 220 can be detachably or non-detachably connected to bolt sleeve 210. In some examples, extension joint 220 is connected to bolt sleeve 210 via threaded connection, flange connection, fastener connection, etc.

[0053] As an example, extension section 220 is a full-length solid cylinder or hollow tube, and its material can be foam, PP or other plastics, metal or other materials. When extension section 220 is a hollow structure, it is filled with silicone, polyurethane foam or other materials.

[0054] The filler 230 is a component disposed between two adjacent bolt sleeves 210 and supported between the first skin layer 110 and the second skin layer 120, used to fill the gap between the bolt sleeves 210 and transmit force. Exemplarily, the filler 230 may be in the shape of an arc block, a cuboid block, a trapezoidal block, a wedge block, etc., adapted to the spacing between two adjacent bolt sleeves 210 and the size of the receiving cavity.

[0055] In one example, the filler 230 may be made of a unidirectional composite material of fiber and resin.

[0056] The filler 230 continuously connects the bolt sleeve 210 and the extension section 220, improving the overall integrity between the bolt sleeve 210 and the extension section 220. In some examples, the length of the filler 230 can be the same as the length of the bolt sleeve 210 and the extension section 220 after connection. Alternatively, the length of the filler 230 can be 80% to 98% of the length of the bolt sleeve 210 and the extension section 220 after connection.

[0057] In some embodiments of this application, the connecting assembly 200 further includes a reinforcing structure 240, and the filler 230 is bonded to the bolt sleeve 210 and the extension section 220 respectively through the reinforcing structure 240. The filler 230, bolt sleeve 210 and extension section 220 are connected by the reinforcing structure 240 to enhance the overall connection strength of the structure.

[0058] For example, the reinforcing structure 240 may be in the shape of a sheet, strip, ring, etc., to adapt to the gap shape between the bolt sleeve 210 and the filler 230 and the gap shape between the extension section 220 and the filler 230.

[0059] There can be one or more reinforcing structures 240. As an example, the reinforcing structures 240 may be multiple and independently installed, or partially connected without being independently installed. However, at least one pair of reinforcing structures 240 connecting the bolt sleeves 210 and the extension section 220 shall be a single unit. That is, the reinforcing structure 240 is continuously connected to the bolt sleeves 210 and the extension section 220, which are arranged along the axial direction X of the bolt sleeves 210.

[0060] In some examples, the reinforcing structure 240 can be a metal component combined with an adhesive, composite material, or other materials. It is connected to the bolt sleeve 210 and the extension joint 220 by an adhesive. As an example, the adhesive can be a matrix 242 such as resin.

[0061] For example, the reinforcement structure 240 can be laid during the laying of the leaf root mold, or it can be connected separately and poured and cured in a designated preform mold.

[0062] By providing a reinforcing structure 240 through adhesive bonding between the filler 230 and the bolt sleeve 210 and extension section 220, the connection strength between the bolt sleeve 210 and the extension section 220 is increased, thereby reducing the risk of low connection strength caused by adhesive bonding alone in the prior art, which makes it easy to delaminate and break under stress.

[0063] In some embodiments of this application, the equivalent elastic modulus of the reinforcing structure 240 is greater than that of the extension section 220 and less than that of the bolt sleeve 210.

[0064] The equivalent elastic modulus is a core equivalent parameter in elasticity mechanics and engineering mechanics. It refers to the equivalent constitutive parameter when a heterogeneous, composite, or complex material / structural system is equivalent to a homogeneous ideal linear elastic material within its elastic deformation range. A unified modulus value characterizes the overall ability of a complex system to resist elastic deformation. The core criteria for equivalence are macroscopic deformation equivalence and elastic strain energy equivalence.

[0065] As an example, the equivalent elastic modulus can be measured using the uniaxial static tension / compression method. The bolt sleeve 210, reinforcing structure 240, and extension section 220 are precisely aligned on the testing machine to eliminate fixture clearances and avoid additional bending moments. Extensometers / strain gauges are installed within the gauge length; direct calculation of deformation (including machine deformation and fixture slippage errors) using the testing machine piston displacement is strictly prohibited. Uniform, graded loading is applied within the elastic range. After each load level stabilizes, the deformation is recorded. Unloading is performed to verify the absence of residual deformation, confirming the load-deformation curve is completely linear. The equivalent stiffness is calculated from the linear segment data, and the final equivalent modulus is calculated. The equivalent elastic moduli of the bolt sleeve 210, reinforcing structure 240, and extension section 220 are then compared.

[0066] As an example, extension joint 220 can be made of lightweight materials such as plastic or foam. Exemplarily, extension joint 220 can be a hollow structure.

[0067] By strengthening the gradual change in the equivalent elastic modulus between structure 240, bolt sleeve 210, and extension section 220, the interface stress between bolt sleeve 210 and extension section 220 is reduced, thereby improving the connection stability between the two. By strengthening the adhesive connection between structure 240, bolt sleeve 210, extension section 220, and filler 230, the force transmission path of connection assembly 200 is further improved, the risk of damage to the connection interface is reduced, and the overall structural reliability of the blade root is enhanced.

[0068] In some embodiments, the equivalent elastic modulus of the reinforcing structure 240 may be less than the equivalent elastic modulus of the filler 230.

[0069] In other embodiments, the equivalent elastic modulus of the reinforcing structure 240 may be greater than that of the filler 230.

[0070] like Figure 3 As shown, in one embodiment of this application, the reinforcing structure 240 includes a porous layer 241 and a substrate 242, with at least a portion of the substrate 242 bonded to the pores of the porous layer 241.

[0071] For example, the porosity of the porous layer 241 is greater than or equal to 70%, which facilitates the full penetration and connection of the substrate 242. The porous layer 241 can be a porous structure formed in the shape of a metal sheet.

[0072] In one example, the elastic modulus of the porous layer 241 should be greater than that of the matrix 242. This ensures that the reinforcing structure 240 has sufficient connection strength and shear resistance.

[0073] In some examples, the porous layer 241 can be bonded to one or more of the bolt sleeve 210, extension joint 220, and filler 230 by functional adhesive or tape.

[0074] In one alternative embodiment of this application, the reinforcing structure 240 includes a braided layer and a substrate 242, with at least a portion of the substrate 242 bonded to the pores of the braided layer.

[0075] The braided layer is a component of the reinforcing structure 240. It is a fiber braid with a porous structure and is used to enhance the mechanical strength of the reinforcing structure 240. The matrix 242 is a material that fills the pores of the braided layer and is bonded to the braided layer. It is used to fix the braided layer and transmit the force.

[0076] For example, the woven layer can be in the shape of a sheet, a bag, or other structures.

[0077] The braided layer can be configured as one or more layers. In some examples, multiple braided layers can be stacked and arranged; located inside or on the surface of the reinforcing structure 240, serving as the skeleton of the reinforcing structure 240.

[0078] In some examples, the woven layer can be made of uniaxial or biaxial fabric. Specifically, the woven layer can be made of materials such as fiber cloth, cotton cloth, plastic mesh, or metal mesh.

[0079] For example, the substrate 242 material can be penetrated into the pores of the braided layer through an impregnation process, and then bonded together after curing; the substrate 242 material can be coated onto the surface of the braided layer through a coating process, allowing some of the substrate 242 material to penetrate into the pores to achieve bonding; or the substrate 242 material can be injected into the pores of the braided layer through a vacuum infusion process to achieve full bonding.

[0080] As an example, a portion of the substrate 242, in its liquid state, permeates and fills the pores of the braided layer, and upon curing, it is fixedly connected to the braided layer. Another portion of the substrate 242 is attached to the surface of the braided layer.

[0081] For example, the substrate 242 can be the same as the curing material of the leaf root, such as epoxy resin, polyurethane resin, phenolic resin, etc. It can also be a resin or adhesive different from the leaf root curing material.

[0082] In this embodiment, the reinforcing structure 240 consists of a braided layer and a substrate 242. The substrate 242 fills the pores of the braided layer, making the braided layer and the substrate 242 form a whole, improving the mechanical strength and toughness of the reinforcing structure 240. At the same time, the substrate 242 can enhance the adhesive connection performance between the reinforcing structure 240 and the bolt sleeve 210 and the filler 230, improve the force transmission effect, further enhance the stability of the connecting assembly 200, and reduce the risk of damage to the connection interface. Furthermore, it can be integrally molded during blade root injection molding, reducing process steps and lowering costs.

[0083] In one alternative embodiment of this application, the braided layer includes a fiber layer.

[0084] For example, it is made of glass fiber woven fabric, carbon fiber woven fabric, aramid fiber woven fabric or a mixture of fibers.

[0085] In this embodiment, the fiber layer can significantly improve the mechanical strength and tensile and shear resistance of the braided layer, thereby enhancing the overall performance of the reinforcing structure 240. This allows the reinforcing structure 240 to better achieve the effect of gradual change in elastic modulus, improve the connection stability between the bolt sleeve 210 and the filler 230, reduce interface damage, and ensure the overall strength of the leaf root.

[0086] Continue to refer to Figure 3 In one specific embodiment of this application, the bolt sleeve 210 is locked to the extension section 220.

[0087] Form-fit connections are achieved by interlocking the shapes of the connected parts or additional fixing parts. The core of this connection lies in the matching of geometric shapes rather than friction.

[0088] In some examples, the bolt sleeve 210 and the extension section 220 can be connected by threads, keys, pins, screws, etc.

[0089] Compared to the interference fit between the bolt sleeve 210 and the extension section 220, the bolt sleeve 210 and the extension section 220 can be connected by a form-locking connection, which has a greater connection strength and a greater tensile strength along the axial direction X, thus improving the overall connection strength and stability of the blade root.

[0090] In one embodiment, the surface of the bolt sleeve 210 is sandblasted and shot-blasted, and then wound with corresponding yarn. A threaded extension 220 is screwed into the end of the bolt sleeve 210. The radius of the extension 220 matches that of the wound bolt sleeve 210, and the threads of the extension 220 and the bolt sleeve 210 are typically manufactured according to the corresponding connection structure and precision.

[0091] In some examples, metal bonding adhesive is applied to the threaded area of ​​extension section 220, and after the threads of extension section 220 are threadedly connected to the tip portion of bolt sleeve 210, it is confirmed that the external dimensions meet the design deviation.

[0092] In one specific embodiment of this application, the bolt sleeve 210 is detachably connected to the extension section 220.

[0093] A detachable connection means that the two parts can be separated and reassembled in a specific way, which facilitates later maintenance and replacement of bolt sleeve 210 or extension section 220.

[0094] In some examples, the bolt sleeve 210 and the extension section 220 can be connected by threads, with one end of the bolt sleeve 210 body having an external thread and one end of the extension section 220 having an internal thread, and the two are threaded together. Alternatively, they can be connected by a snap-fit ​​mechanism, with the bolt sleeve 210 body having a protrusion and the extension section 220 having a slot, the protrusion engaging and securing with the slot. Finally, they can be connected by a pin; after the bolt sleeve 210 and the extension section 220 are mated, a pin is inserted to secure them, and removing the pin allows for separation.

[0095] In this embodiment, the bolt sleeve 210 and the extension section 220 are detachably connected, so that during the use of the blade root, the corresponding parts can be replaced individually according to the wear and damage of the bolt sleeve 210 or the extension section 220, without having to replace the entire connecting assembly 200, reducing maintenance costs and improving the maintenance convenience of the blade root. At the same time, extension sections 220 of different lengths can be replaced according to actual installation needs, improving the adaptability of the blade root.

[0096] like Figures 2 to 4 As shown, in one specific embodiment of this application, a porous layer 241 surrounds the periphery of the bolt sleeve 210 and the extension section 220.

[0097] The connecting assembly 200 includes one or more reinforcing structures 240, that is, the bolt sleeve 210 assembly consisting of the bolt sleeve 210 and the extension section 220 has multiple bolt sleeve 210 assemblies, and some or all of the multiple bolt sleeve 210 assemblies are surrounded by a porous layer 241 of the reinforcing structure 240.

[0098] For example, the porous layer 241 has an annular cross-section, which can be a closed annulus, an open annulus, or an annulus with overlapping layers in the circumferential direction V. The porous layer 241 extends along the axial direction X of the bolt sleeve 210. As an example, when the cross-section of the porous layer 241 is an open annulus, its opening angle is less than 30 degrees.

[0099] In some examples, the area of ​​the porous layer 241 covering the bolt sleeve 210 and the extension joint 220 accounts for 70% to 100% of the total surface area of ​​the bolt sleeve 210 and the extension joint 220.

[0100] In some examples, the porous layer 241 may be entirely located between the bolt sleeve 210 assembly and the filler 230, or a portion of the porous layer 241 may be located between the bolt sleeve 210 assembly and the filler 230, with a portion extending beyond the filler 230 and connecting to the leaf root skin structure 100.

[0101] In this embodiment, the porous layer 241 surrounds the periphery of the bolt sleeve 210 assembly, which can constrain and strengthen the bolt sleeve 210 assembly from the outside, reduce the radial deformation of the bolt sleeve 210 assembly during the stress process, optimize the force transmission between the bolt sleeve 210 and the filler 230, improve the overall rigidity of the connecting assembly 200, reduce the risk of damage to the connection interface, and thus improve the overall structural stability of the leaf root.

[0102] In some embodiments, filler 230 is laid on an operating platform, and bolt sleeves 210 and extension sections 220, which are bonded together with porous layers 241, are placed between two adjacent filler 230. The operating platform can be located inside or outside the mold.

[0103] In some embodiments, the porous layer 241 is wound along the axial direction X around the bolt sleeve 210 and the extension joint 220. As an example, the reinforcing structure 240 can be fixed in one turn every 100 mm.

[0104] In some embodiments, the axial X-winding length of the porous layer 241 covers at least a portion of the bolt sleeve 210, or covers both the bolt sleeve 210 and a portion of the extension section 220. As an example, the porous layer 241 of the extension section 220 may or may not be cut.

[0105] In some embodiments, the filler 230 is placed symmetrically and centrally above the sheet-like porous layer 241, with the center line of the filler 230 aligned with the center line of the width of the porous layer 241. The connected bolt sleeve 210 and extension section 220 are placed in the corresponding positions so that they are flush with the end of the filler 230 and the ramp section is aligned with the tolerance of ±1mm.

[0106] like Figure 4 As shown, in a specific embodiment of this application, the filler 230 is provided with a groove 231 along the circumferential direction V of the leaf root, and the groove 231 is recessed from the bolt sleeve 210 toward the middle of the filler 230; the porous layer 241 is accommodated in the groove 231, and the bolt sleeve 210 is accommodated in the groove 231.

[0107] For example, the groove 231 may be in the shape of an arc-shaped groove 231, a rectangular groove 231, a trapezoidal groove 231, etc., to match the shape of the reinforcing structure 240 and the bolt sleeve 210 assembly.

[0108] In some examples, the filler 230 is along the axial direction X of the bolt sleeve 210, and the groove 231 includes a first groove segment and a second groove segment. The first groove segment is used to receive the bolt sleeve 210, and the second groove segment is used to receive at least a portion of the extension section 220. That is, the shape of the first groove segment matches the bolt sleeve 210, and the shape of the second groove segment matches the extension section 220.

[0109] In some examples, the filler 230 has two opposing grooves 231 along the circumferential V, each accommodating two adjacent bolt sleeves 210.

[0110] For example, the bolt sleeve 210 is partially or entirely accommodated within the grooves 231 of two adjacent fillers 230.

[0111] In one example, the porous layer 241 is wholly or partially contained within the groove 231.

[0112] For example, the porous layer 241 can be embedded in the groove 231 and fixed by adhesive connection; the reinforcing structure 240 can be interference-fitted with the groove 231 to achieve a tight fit.

[0113] A groove 231 is provided on the filler 230, and the porous layer 241 and part of the bolt sleeve 210 are accommodated in the groove 231, which makes the installation of the porous layer 241 more stable, reduces the displacement of the porous layer 241 during the stress process, and increases the contact area between the porous layer 241 and the filler 230 and bolt sleeve 210, optimizes the stress transmission effect, further improves the connection stability, and reduces the risk of delamination and cracking at the connection interface.

[0114] like Figure 5 and Figure 6 As shown, in some optional embodiments of this application, the porous layer 241 includes a first portion 241a, a second portion 241b, and a third portion 241c extending along its own length direction. The first portion 241a is bonded to the blade root skin structure 100 and the bolt sleeve 210, and is also bonded to the blade root skin structure 100 and the extension section 220. The second portion 241b is bonded to the blade root skin structure 100 and the filler 230. The third portion 241c is bonded to the bolt sleeve 210 and the filler 230, and is also bonded to the extension section 220 and the filler 230.

[0115] For example, the first part 241a, the second part 241b and the third part 241c may be continuous with each other, independent of each other, or any two of them may be arranged continuously.

[0116] In one example, the first part 241a and the second part 241b are set consecutively and independently of the third part 241c.

[0117] In another example, the first part 241a and the third part 241c are set consecutively and independently of the second part 241b.

[0118] In yet another example, the second part 241b and the third part 241c are set consecutively and independently of the first part 241a.

[0119] The lengths of the first part 241a, the second part 241b, and the third part 241c along the axial direction X of the bolt sleeve 210 may be the same or different.

[0120] like Figure 6 As shown, in some optional embodiments of this application, the porous layer 241 includes a first portion 241a, a second portion 241b, and a third portion 241c extending along its own length direction. The first portion 241a and the second portion 241b are continuously disposed. The first portion 241a is bonded to the blade root skin structure 100 and the bolt sleeve 210 and to the extension section 220. The second portion 241b is bonded to the blade root skin structure 100 and the filler 230. The third portion 241c is bonded to the bolt sleeve 210 and the filler 230 and to the extension section 220 and the filler 230.

[0121] For example, the first part 241a, the second part 241b and the third part 241c are arranged consecutively, or the third part 241c is independent of the first part 241a and the second part 241b.

[0122] In one example, the first portion 241a includes two opposing first surfaces along the thickness direction of the porous layer 241, one first surface being connected to one of the first skin layer 110 and the second skin layer 120, and the other first surface being bonded to both the bolt sleeve 210 and the extension joint 220.

[0123] In one example, the second part 241b includes two opposing second surfaces along the thickness direction, one second surface being connected to one of the first skin layer 110 and the second skin layer 120, and the other second surface being bonded to the filler 230.

[0124] For example, the first surface and the second surface may be connected to the same one of the first skin layer 110 and the second skin layer 120, or both may be connected separately.

[0125] In one example, the second part 241b includes two opposing third surfaces along the thickness direction, one third surface being bonded to both the bolt sleeve 210 and the extension section 220, and the other third surface being bonded to the filler 230.

[0126] In related technologies, without the porous layer 241, the bolt sleeve 210, extension section 220, filler 230, and blade root skin structure 100 are all in multiphase heterogeneous interface contact. This results in insufficient connection strength between interfaces, poor force transmission, and stress concentration at each connection interface, leading to delamination, peeling, and other damage, thus reducing the overall structural stability and connection reliability of the blade root. However, the reinforcing structure 240 in this embodiment, through the first part 241a, the second part 241b, and the third part 241c respectively bonding and connecting the interfaces of each component, effectively improves the above problems, optimizes the force transmission path between the four components, reduces stress concentration at each connection interface, and enhances the overall structural stability and strength of the blade root. Furthermore, the continuous arrangement of the first part 241a and the second part 241b improves the connection strength between the bolt sleeve 210 assembly and the filler 230, while further enhancing the connection strength with the blade root skin structure 100.

[0127] like Figure 5 As shown, in a specific embodiment of this application, the first part 241a, the second part 241b, and the third part 241c are arranged consecutively.

[0128] The porous layer 241 has one or more sets of continuously arranged first portions 241a, second portions 241b and third portions 241c. Exemplarily, the multiple sets of continuously arranged first portions 241a, second portions 241b and third portions 241c may be independent of each other or continuous with each other.

[0129] For example, the first and second parts of the third part 241c are connected to the first part 241a and the second part 241b respectively.

[0130] In some examples, the first portion 241a, the second portion 241b, and the third portion 241c have the same length along the axial direction X of the bolt sleeve 210. As an example, the porous layer 241 is a rectangular fabric layer.

[0131] The first part 241a, the second part 241b, and the third part 241c are arranged continuously, which reduces the connection gaps of the reinforcing structure 240 itself, improves the overall strength and toughness of the reinforcing structure 240, and allows the force to be smoothly transmitted inside the reinforcing structure 240. This avoids damage caused by the concentration of force at the splicing points of the porous layer 241 itself, further improves the stability of each connection interface, and reduces the risk of damage to the leaf root structure.

[0132] In one embodiment of this application, the first part 241a is bonded between the first skin layer 110 and the bolt sleeve 210 and between the first skin layer 110 and the extension section 220, and the second part 241b is bonded between the second skin layer 120 and the filler 230.

[0133] For example, the porous layer 241 is arranged in a "Z" shape within the connecting component 200. That is, the first part 241a and the second part 241b are distributed along the inner edge of the connecting component 200, and there is no overlap between the first part 241a and the second part 241b in the radial orthographic projection plane.

[0134] In some examples, the first skin layer 110 can be one of the inner skin layer and the outer skin layer, and the second skin layer 120 can be the other.

[0135] In this embodiment, the first part 241a is bonded to the first skin layer 110 and the bolt sleeve 210, and the second part 241b is bonded to the second skin layer 120 and the filler 230. Compared with the method where both the first part 241a and the second part 241b are connected to the first skin layer 110 or both to the second skin layer 120, this method has significant advantages: Firstly, it can achieve the distributed transmission of force, avoiding excessive connection stress on a single skin layer and reducing the risk of damage to a single skin layer due to stress concentration. Secondly, it allows the force on the bolt sleeve 210 and the filler 230 to be transmitted through their respective skin layers, which is superior. First, it optimizes the stress distribution of the entire blade root; second, it adapts to the radial layout of the blade root skin structure 100, with the first skin layer 110 and the second skin layer 120 distributed radially and connected to the bolt sleeve 210 and the filler 230 respectively, which allows the reinforcing structure 240 to fit more closely to the connection interface of each component, improves the tightness of the adhesive connection, reduces interface gaps, and reduces the risk of delamination; third, it can take into account the connection stability of the inner and outer radial sides of the blade root, avoiding the weak connection between the other skin layer and the component due to both being connected to the same skin layer, further improving the overall structural rigidity and connection reliability of the blade root, and better adapting to the stress requirements of the wind turbine blade root.

[0136] In some embodiments, the thickness, equivalent elastic modulus, and other parameters of the first part 241a, the second part 241b, and the third part 241c may be the same or different.

[0137] In some embodiments, the thicknesses of the first portion 241a, the second portion 241b, and the third portion 241c can be uniformly set. Based on the different gaps between the leaf root skin structure 100, the bolt sleeve 210, the extension section 220, and the filler 230, the thickness and filling amount of the substrate 242 can be different.

[0138] Continue to refer to Figure 5 Furthermore, in some optional embodiments of this application, the first skin layer 110 is an inner skin layer, and the second skin layer 120 is an outer skin layer.

[0139] The inner skin layer can directly contact the inner side of the connecting component 200, while the outer skin layer is located at the outermost edge of the leaf root and is in contact with the external environment. The outer skin layer covers the inner skin layer, thus the outer skin layer is more susceptible to external damage.

[0140] For example, the inner skin layer can be thicker than the outer skin layer to improve internal support strength. Alternatively, the outer skin layer can be thicker than the inner skin layer to improve external protective performance.

[0141] In some examples, a second portion 241b is connected between the outer skin layer and the filler 230, and a first portion 241a is connected between the inner skin layer and the bolt sleeve 210 assembly.

[0142] In some examples, the orthographic projection of filler 230 lies within the orthographic projection of second part 241b in the radial orthographic projection.

[0143] In this embodiment, considering that the strength of the filler 230 is lower than that of the bolt sleeve 210, the reinforcing structure 240 can cover the filler 230 on the outside (the outer skin layer side), which is more conducive to improving the overall strength of the blade root. Since the filler 230 is weaker, when the blade root is subjected to external impact, the outer reinforcing structure 240 can play a buffering and protective role, effectively resisting the impact force on the filler 230, reducing the risk of damage or breakage of the filler 230, and thus avoiding the stress imbalance of the connecting component 200 due to damage to the filler 230, further improving the overall structural stability and service life of the blade root. At the same time, the clear positioning of the skin layer also facilitates the precise covering and arrangement of the reinforcing structure 240.

[0144] In an alternative embodiment of this application, the porous layer 241 continuously covers all bolt sleeves 210, all extension sections 220, and all fillers 230.

[0145] Continuous wrapping refers to the fact that the reinforcing structure 240 is an uninterrupted ring-shaped integral structure, which completely wraps all the bolt sleeves 210 and all the fillers 230, forming a complete wrapping layer without splicing gaps.

[0146] In other words, the porous layer 241 can be an integral elongated structure. For example, the reinforcing structure 240 includes a first connecting end and a second connecting end along its length direction, wherein the first connecting end and the second connecting end overlap, are connected end-to-end, or the distance between the first connecting end and the second connecting end is less than or equal to 20 cm.

[0147] In this embodiment, the porous layer 241 continuously covers all bolt sleeves 210, all extension sections 220 and fillers 230, so that all bolt sleeves 210, extension sections 220 and fillers 230 form an integral force-bearing unit. The force can be evenly transmitted inside the entire connection assembly 200, reducing stress concentration in a single bolt sleeve 210 or filler 230, improving the overall stability of the connection assembly 200, and thus improving the overall strength and damage resistance of the blade root.

[0148] Specifically, such as Figure 7 As shown, in some embodiments of this application, the connecting component 200 further includes a protrusion disposed between the bolt sleeve 210 and the filler 230, and connected to the porous layer 241.

[0149] For example, the protrusions may be cylindrical, square, or arc-shaped. The number of protrusions may be one or more; in some examples, multiple protrusions may be provided between each bolt sleeve 210 and the filler 230.

[0150] In some examples, the protrusion may be integrally formed with the bolt sleeve 210, integrally formed with the filler 230, or set independently.

[0151] In some examples, the protrusion is disposed between the extension 220 and the filler 230 and is connected to the porous layer 241.

[0152] In some examples, the material of the protrusion may be the same as that of the bolt sleeve 210 or the filler 230, or it may be a composite material adapted to the reinforcing structure 240.

[0153] In one example, the radial dimension of the protrusion is ≤1mm.

[0154] For example, the protrusion and the porous layer 241 can be connected by adhesive bonding, or the protrusion can be embedded inside the reinforcing structure 240 to achieve mechanical connection, or it can be engaged with the porous layer 241 by a slot on the protrusion.

[0155] In this embodiment, the protrusion is disposed between the bolt sleeve 210 and the filler 230 and connected to the porous layer 241, which can increase the contact area between the reinforcing structure 240 and the bolt sleeve 210 and the filler 230, increase the connection points between the reinforcing structure 240 and the bolt sleeve 210 and the filler 230, improve the connection strength, optimize the force transmission path, further reduce the risk of damage to the connection interface, and improve the overall structural stability of the leaf root.

[0156] In some embodiments, the protrusions are bonded to designated positions on the filler 230, with multiple protrusions evenly spaced 10-15 mm apart. Pressure rollers or plates are used to press and fix the protrusions, bonding them to the outside of the filler 230 surface to form an interface-reinforced connecting strip.

[0157] Furthermore, in some optional embodiments of this application, the filler 230 is provided with a groove 231 along the circumferential direction V of the leaf root, the groove 231 is recessed from the bolt sleeve 210 toward the center of the filler 230; the protrusion is provided on the wall surface of the groove 231.

[0158] For example, the protrusion can be provided on the bottom surface, side surface or corner of the groove 231, and can be integrally formed with the wall surface of the groove 231, or can be bonded and fixed to the wall surface of the groove 231; the size of the protrusion is adapted to the size of the groove 231 and does not exceed the range of the groove 231, ensuring that the porous layer 241 can be smoothly accommodated in the groove 231 and connected to the protrusion.

[0159] In some examples, the protrusion can be integrally formed on the inner sidewall of the groove 231 and protrude toward the center of the groove 231; the protrusion can be fixed to the bottom surface of the groove 231 by welding or adhesive connection and contact the bottom of the reinforcing structure 240; the connection between the protrusion and the reinforcing structure 240 can be achieved by embedding the protrusion into the reinforcing structure 240 or by adhesive connection to ensure a firm connection.

[0160] In this embodiment, the protrusion is disposed on the wall of the groove 231, so that the protrusion, the groove 231, and the reinforcing structure 240 form an integral whole, further improving the installation stability of the reinforcing structure 240. At the same time, the protrusion can enhance the connection strength between the reinforcing structure 240 and the filler 230, optimize the force transmission, reduce the interface damage between the reinforcing structure 240 and the filler 230, and thus improve the overall structural reliability of the leaf root.

[0161] In some embodiments of this application, the blade root structure is a blade root prefabricated component, including: a blade root skin structure 100, including a first skin layer 110 and a second skin layer 120 stacked together, with a receiving cavity formed between the first skin layer 110 and the second skin layer 120; a connecting assembly 200 connected to the receiving cavity, the connecting assembly 200 including a bolt sleeve 210, an extension section 220, a filler 230 and a reinforcing structure 240, the extension section 220 being connected to one end of the bolt sleeve 210 along its own length direction, the filler 230 being disposed on one side of the bolt sleeve 210 in the radial direction, the filler 230 being supported between the first skin layer 110 and the second skin layer 120, and the reinforcing structure 240 being bonded to the filler 230 and the bolt sleeve 210 and the extension section 220 respectively; wherein, the equivalent elastic modulus of the reinforcing structure 240 is greater than the equivalent elastic modulus of the extension section 220 and less than the equivalent elastic modulus of the bolt sleeve 210.

[0162] For example, multiple blade root preforms can be connected to form a ring-shaped blade root. The multiple blade root skin structures 100 can be integrally molded or bonded together.

[0163] Some embodiments of this application provide a wind turbine blade, including the blade root structure of the wind turbine blade described in the above embodiments.

[0164] Some embodiments of this application provide a method for forming a leaf root structure, including placing a pre-embedded flange fixture on the base of a designated bracket or mold, placing a sealing strip on the surface, and cleaning it.

[0165] Insert the positioning bolts, and then insert the assembled bolt sleeve 210, extension section 220, filler 230, and reinforcing structure 240 into the tooling bolts as a whole, ensuring that the pin hole is aligned with the pin in the bolt sleeve 210 hole. After alignment, press firmly by hand. First, use a manual wrench to make the positioning bolts fit firmly against the outside of the flange, and then use a torque wrench to install and fix the positioning bolts.

[0166] After laying the outer skin fabric layer on the mold and inspecting it to ensure it is qualified, lift the flange fixture and place the bolt sleeve 210, extension section 220, filler 230 and reinforcing structure 240 into the positioning base, and then lay the inner skin fabric layer in sequence.

[0167] A perforated release membrane, a flow guide, a glue channel, and a glue inlet can be laid on the inner surface of the mold at designated locations. The glue inlet is connected to the external resin inlet pipe. Evacuation material is laid along the front and rear flanges of the mold, with the material overlapping the fabric layer by a certain dimension, and an external vacuum pump is connected. An absolute pressure gauge is inserted into the vacuum system, and a vacuum membrane is sealed, typically two layers. The vacuum pump is turned on, and the vacuum value is evacuated to a certain range. The vacuum pressure drop is tested over a certain period. The absolute pressure gauge reading should rise by less than 2 kPa over 15 minutes. Pressure is monitored using a pressure gauge throughout the entire filling process. Alternatively, a digital vacuum gauge can be used to maintain pressure; once the vacuum pressure is ≤-98 kPa and stable, pressure maintenance begins, and the pressure maintenance requirement remains unchanged. During the filling process, the glue inlets are opened sequentially, and the valves are closed after the fabric layer is completely saturated. Residual glue in the glue inlet pipe is removed, and the work area is cleaned.

[0168] Before pouring, turn on the mold heater, set the curing regime, preheat for a certain time, and insulate special areas. After pouring, turn on the mold heater according to the curing regime. During the resin exothermic process, perform water bath cooling on the mold surface. After the exothermic peak has passed, cover the entire mold with a cotton quilt for insulation. The insulation requirement is to keep the skin at the specified temperature for the specified duration. After the blade root area and the bonding joint corner are completely cured, the curing is considered complete.

[0169] Some embodiments of this application provide a method for forming wind turbine blades, including: a) Laying process: Clean the mold surface, apply release agent, and then lay release cloth and other auxiliary materials on the mold surface in sequence.

[0170] The outer skin and reinforcement are laid on the surface of the mold, and the prefabricated structural components such as beams and leaf roots are placed using lifting tools.

[0171] Above the outer skin, along the chordal boundary positioning line, fiber fabric or laminate, core material, and the upper fabric or laminate are laid in sequence. The core material thickness can range from 5mm to 80mm, and the core material is designed with corresponding chamfers of 1:3 to 1:200 around its perimeter. The fiber fabric can be single-layered or multi-layered, and can be uniaxial or biaxial fibers. Carbon fiber or glass fiber can be selected according to the structural design, and the modulus can be selected from low to high, or combined and laid according to the structural design. Multi-layered fibers need to be delaminated according to the structural design principles.

[0172] After laying the appropriate fabric layers and the structural layers are completed, release fabric and other auxiliary materials are laid on the surface.

[0173] b) Establishment of the infusion system and vacuum system On the inner surface, lay the perforated isolation membrane, flow guide, glue channel and glue inlet at the designated positions.

[0174] The injection port is connected to the external resin inlet pipe.

[0175] Evacuation material is laid along the front and rear flanges of the mold, with the material overlapping the fabric layer by a certain dimension, and an external vacuum pump is connected. An absolute pressure gauge is inserted into the vacuum system, and a vacuum diaphragm is sealed, typically wrapped with two layers of diaphragm.

[0176] Turn on the vacuum pump and evacuate to a certain vacuum level. Test the vacuum pressure drop over a certain period of time. The absolute pressure gauge reading should rise by less than 2 kPa over 15 minutes. Monitor the pressure using a pressure gauge throughout the entire priming process. Alternatively, a digital vacuum gauge can be used to maintain the pressure. Begin maintaining the pressure once the vacuum pressure is ≤-98 kPa and stable, and the pressure maintenance requirement remains the same.

[0177] c) Resin infusion and curing During the injection process, open the injection ports in sequence, and close the valve after the fabric layer is completely soaked. Remove any remaining adhesive from the injection tube and clean the site.

[0178] Before pouring, turn on the mold heater, set the curing regime, preheat for a certain time, and insulate special areas. After pouring, turn on the mold heater according to the curing regime. During the resin exothermic process, perform water bath cooling on the mold surface. After the exothermic peak has passed, cover the entire mold with a cotton quilt for insulation. The insulation requirement is to keep the skin at the specified temperature for the specified duration. After the blade root area and the bonding joint corner are completely cured, the curing is confirmed to be complete. d) Mold closing and bonding After curing, the web and other designated components are bonded to the designated positions on the skin in sequence. Structural adhesive is applied and the mold is closed and locked. The blade is heated and cured for a specified time. After curing, the blade is demolded, the blank is finished, painted, and assembled to obtain the final blade product.

[0179] The above are merely specific embodiments of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A root structure for a wind turbine blade, characterized in that, include: The leaf root skin structure includes a first skin layer and a second skin layer arranged radially thereon, and a receiving cavity is formed between the first skin layer and the second skin layer. A connecting assembly is connected to the receiving cavity. The connecting assembly includes multiple bolt sleeves, multiple extension sections, multiple fillers, and a reinforcing structure. The multiple bolt sleeves are spaced apart circumferentially along the leaf root skin structure. The extension sections are connected to one end of each bolt sleeve along its own length direction. The filler is disposed between two adjacent bolt sleeves. The filler is supported between the first skin layer and the second skin layer. The reinforcing structure is bonded to the filler and the bolt sleeves and extension sections, respectively. The equivalent elastic modulus of the reinforcing structure is greater than that of the extension section and less than that of the bolt sleeve.

2. The blade root structure of the wind turbine blade according to claim 1, characterized in that, The bolt sleeve is locked to the extension section.

3. The blade root structure of the wind turbine blade according to claim 1 or 2, characterized in that, The reinforcing structure includes a porous layer and a matrix, wherein at least a portion of the matrix is ​​bonded to the pores of the porous layer; or, the porous layer includes a woven layer. And / or, the porous layer surrounds the periphery of the bolt sleeve and the extension section.

4. The blade root structure of the wind turbine blade according to claim 3, characterized in that, The porous layer includes a first portion, a second portion, and a third portion extending along its own length direction. The first portion and the second portion are continuously arranged, or the first portion, the second portion, and the third portion are continuously arranged. The first portion is bonded to the blade root skin structure and the bolt sleeve, and is also bonded to the blade root skin structure and the extension section. The second portion is bonded to the blade root skin structure and the filler. The third portion is bonded to the bolt sleeve and the filler, and is also bonded to the extension section and the filler. And / or, the porous layer continuously covers all of the bolt sleeves, all of the extension sections, and all of the fillers.

5. The blade root structure of the wind turbine blade according to claim 4, characterized in that, The first part, the second part, and the third part are continuously arranged. The first part is bonded between the first skin layer and the bolt sleeve and between the first skin layer and the extension section. The second part is bonded between the second skin layer and the filler.

6. The blade root structure of the wind turbine blade according to claim 5, characterized in that, The first skin layer is the inner skin layer, and the second skin layer is the outer skin layer.

7. The blade root structure of the wind turbine blade according to claim 3, characterized in that, The filler is provided with a groove along the circumference of the leaf root, and the groove is recessed from the bolt sleeve toward the center of the filler; The porous layer is accommodated in the groove, and the bolt sleeve is accommodated in the groove.

8. The blade root structure of the wind turbine blade according to claim 3, characterized in that, The connecting assembly further includes a protrusion disposed between the bolt sleeve and the filler, and connected to the porous layer.

9. The blade root structure of the wind turbine blade according to claim 8, characterized in that, The filler is provided with a groove along the circumference of the leaf root, and the groove is recessed from the bolt sleeve toward the center of the filler; The protrusion is disposed on the wall surface of the groove.

10. A wind turbine blade, characterized in that, The blade root structure includes any one of claims 1 to 9.

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