Intelligent morphing wind turbine blade with sparse structure

Abstract

The application relates to a sparse-structure intelligent deformation wind turbine blade. The application is suitable for the technical field of wind power generation devices. The application aims to provide a sparse-structure intelligent deformation wind turbine blade. The application adopts the technical scheme that the sparse-structure intelligent deformation wind turbine blade comprises a strain layer, a main vein and a plurality of side veins, the side of the main vein is provided with the plurality of side veins at a preset angle interval, the main vein can provide longitudinal main support, the main vein and the plurality of side veins are made of shape memory polymers, the strain layer can be bent-torsion coupling deformation when reaching a preset temperature threshold, and the strain layer can adapt to wind speed changes; a passive base layer is arranged at the bottom of the strain layer and can provide deformation constraint for the main vein and the side veins; the passive base layer and the strain layer cooperatively form a double-layer composite beam structure; and a blade root mounting part is arranged at the blade root end of the strain layer and the passive base layer and is used for corresponding connection with the hub of the wind turbine.

Description

Technical Field

[0001] This utility model relates to the field of wind power generation equipment technology, and in particular to a sparse structure intelligent deformable wind turbine blade. Background Technology

[0002] Currently, in micro wind power systems, wind turbine blades are mostly made of rigid composite materials, which are difficult to adapt to load changes caused by wind speed variations during operation, making them prone to fatigue failure. Furthermore, while flexible blades can alleviate some load, they are susceptible to flutter and instability. Regarding the design mimicking natural forms, research has shown that the main-lateral vein configuration of plant leaves possesses excellent mechanical properties in terms of load-bearing and deformation; however, due to manufacturing difficulties and structural complexity, there are currently no mature industrialized structural products. In addition, the structure of a complete plant leaf has disadvantages such as a large wind-exposed surface area, susceptibility to flutter, high material costs, and heavy weight. Therefore, this application proposes a sparsely structured intelligent deformable wind turbine blade that comprehensively reduces the amount of material used in manufacturing the blade, helping to reduce its weight and cost. Summary of the Invention

[0003] The technical problem to be solved by this utility model is to provide a sparse structure intelligent deformable wind turbine blade to address the above-mentioned problems.

[0004] The technical solution adopted in this utility model is: a sparse-structured intelligent deformable wind turbine blade, comprising: The strain layer includes a main vein and multiple side veins. Multiple side veins are provided on the sides of the main vein at preset angles. The main vein can provide longitudinal main support. The main vein and multiple side veins are made of shape memory polymer, which enables the strain layer to undergo bending-torsion coupling deformation when a preset temperature threshold is reached to adapt to wind speed changes. The passive base layer, located at the bottom of the strain layer, can provide deformation constraints for the main vein and the side veins. The passive base layer and the strain layer together form a double-layer composite beam structure. The blade root mounting section is located at the blade root end between the strain layer and the passive substrate layer, and is used to connect to the hub of the wind turbine.

[0005] Using the above-mentioned technical means, shape memory polymers are used to make the main vein and side veins. The main vein and side veins form a strain layer with deformability and a sparse structure. The strain layer and the passive base layer are combined to form a double-layer composite beam structure, which can provide structural stability and deformation constraints while providing deformation freedom. When the blade as a whole reaches the preset temperature threshold, it can perform bending-torsion coupling deformation. By adapting to the load fluctuation caused by wind speed changes through appropriate deformation, fatigue damage is reduced.

[0006] In some embodiments, the number of lateral veins is not less than 10, and the width of the lateral veins gradually decreases from the leaf root to the leaf tip, with the width of the lateral vein at the leaf root being 10 times the width of the lateral vein at the leaf tip.

[0007] In some embodiments, the preset angle γ formed by the intersection of the side of the main vein away from the lateral vein and the axis where the lateral vein is located is 45°.

[0008] In some embodiments, the material of the shape memory polymer includes PLA material.

[0009] In some embodiments, the main vein and the side veins are formed by FDM 3D printing.

[0010] In some embodiments, the preset temperature threshold is 60℃~110℃.

[0011] In some embodiments, the passive substrate layer comprises a paper film.

[0012] The beneficial effects of this utility model are: 1. By employing a sparse structure biomimetic design, key load-bearing structures such as the midrib and lateral veins are retained, while the complete leaf surface structure is eliminated to form a strain layer. The strain layer retains the excellent mechanical properties of plant leaf structures and reduces material usage, weight, and cost. Simultaneously, the midrib and lateral vein structures are made of shape memory polymers, enabling the blade to undergo bending-torsional coupling deformation when a preset temperature threshold is reached. This deformation capability allows the blade to actively adapt to load fluctuations caused by wind speed changes, thereby alleviating stress concentration, reducing fatigue damage, and extending the blade's service life. A double-layer composite beam structure is formed by the passive base layer and the strain layer, providing both deformation freedom and structural stability and deformation constraints. Using the passive base layer as structural support can suppress excessive blade deformation and flutter behavior, thus maintaining aerodynamic stability while preserving a certain degree of flexibility. Attached Figure Description

[0013] Figure 1 This is a plan view of this application.

[0014] Figure 2 This is a side view of the present application.

[0015] Figure 3 This is a schematic diagram illustrating the blade deformation capability principle in this application.

[0016] Figure 4 This is a comparison of the blade morphology before and after thermal activation in this application.

[0017] Figure 5 This is a schematic diagram of the installation of the blades and the wind turbine hub in this application.

[0018] Explanation of reference numerals in the attached figures: 1. Midrib; 2. Lateral veins; 3. Passive basal layer; 4. Leaf root mounting part.

[0019] This specification includes references to "one embodiment" or "implementation". The use of the phrase "in one embodiment" or "in an embodiment" does not necessarily refer to the same embodiment. Specific features, structures, or characteristics may be combined in any suitable manner consistent with this disclosure.

[0020] The term "comprising" is open-ended. As used in the appended claims, it does not exclude additional structures or steps.

[0021] "First," "second," etc. As used in this article, these terms serve as labels for the nouns preceding them and do not imply any type of ordering (e.g., spatial, temporal, logical, etc.).

[0022] The term "based on," as used herein, describes one or more factors that influence the determination. This term does not exclude additional factors influencing the determination. That is, the determination may be based solely on these factors or at least partially on them. Consider the phrase "A is determined based on B." In this case, B is the factor influencing the determination of A, and such phrases do not exclude the possibility that the determination of A may also be based on C. In other instances, A may be determined solely on B. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be further described below with reference to specific embodiments.

[0024] Example 1: Combination Figures 1 to 5 As shown, this embodiment is a sparsely structured intelligent deformable wind turbine blade, including a strain layer, a passive base layer 3, and a blade root mounting part 4. The passive base layer 3 is located at the bottom of the strain layer, and the blade root mounting part 4 is located at the blade root end of both the strain layer and the passive base layer 3. The blade root mounting part 4 is used to connect with the hub of the wind turbine. The strain layer includes a main vein 1 and multiple side veins 2. The side veins 2 are located at a preset angle on the sides of the main vein 1, and the multiple side veins 2 are arranged at intervals along the sides of the main vein 1. The main vein 1 can provide longitudinal main support. The main vein 1 and the multiple side veins 2 are all made of shape memory polymer, which allows the strain layer to undergo bending-torsional coupling deformation when a preset temperature threshold is reached to adapt to wind speed changes. The passive base layer 3 located at the bottom of the strain layer can provide deformation constraints for the main vein 1 and the side veins 2, so that the passive base layer 3 and the strain layer cooperate to form a double-layer composite beam structure.

[0025] In this embodiment, the blade forms an asymmetric stress distribution through a composite structure of main vein, lateral vein, and passive base layer. Under the influence of wind speed changes leading to surface temperature rise, the molecular chains of the shape memory polymer (SMP) material rearrange, causing the blade to evolve from a planar state to a three-dimensional torsional-bending state. This deformation mechanism can be summarized as: "Increased wind speed → Enhanced blade surface friction and eddy current disturbance → Localized temperature increase → Material activation → Blade deformation (tip twisting, bending) → Change in aerodynamic load distribution → Optimization of wind energy capture efficiency → Reduction of overload and flutter." This process requires no electronic control system, can dynamically respond to changes in environmental wind conditions, and possesses biomimetic active adaptive capabilities, making it particularly suitable for small or distributed wind power systems.

[0026] In some implementation schemes, such as Figure 1 and Figure 2 As shown, there are no fewer than 10 lateral veins 2. The width of the lateral veins 2 gradually decreases from the leaf root to the leaf tip of the main vein 1. The specific dimensions are adjusted according to engineering requirements. However, it is generally necessary to meet the following requirement: the width of the lateral vein 2 at the leaf root is 10 times the width of the lateral vein 2 at the leaf tip, thus forming a branching structure similar to that of a plant leaf. Specifically, in this embodiment, there are a total of 10 lateral veins 2.

[0027] In some implementations, the preset included angle γ formed by the intersection of the side of the main vein 1 away from the lateral vein 2 and the axis where the lateral vein 2 is located is 45°.

[0028] In some implementations, the shape memory polymer (SMP) material includes PLA, a relatively mature material. The main vein 1 and side veins 2 are formed using FDM (Fused Deposition Modeling) 3D printing, a process that utilizes heated and molten thermoplastic material, stacking it layer by layer through a nozzle to build a three-dimensional structure. After printing, the main vein 1 maintains its predetermined shape at room temperature. When heated to its glass transition temperature (typically above 60°C), the material's molecular chains rearrange, driving the structure to recover its preset shape, thus achieving reversible bending-torsional coupling deformation. This process requires no external driving mechanism, giving the blade the ability to adaptively respond to changes in the external environment. Furthermore, PLA is a biodegradable material, low-carbon and environmentally friendly, with low manufacturing costs, and can be mass-produced.

[0029] Shape memory polymers exhibit a unidirectional shape memory effect, requiring repeated thermal activation to switch between two states; the cooling process only serves to fix the shape. Shape memory polymers (such as PLA-SMP) have a unidirectional shape memory effect, meaning that after being heated and deformed from a "programmed state" to a "memory state," they will retain that shape after the temperature decreases. Only when the temperature is raised again above their glass transition temperature will they return to their initial shape. Therefore, their state switching follows a cycle of "heat activation → deformation / recovery → cooling lock-in."

[0030] FDM 3D printing is suitable for manufacturing complex geometries, simplifying the manufacturing process and reducing manufacturing costs. The blade structure in this embodiment is more suitable for micro wind turbine blades or experimental verification devices, mainly targeting small and medium-sized systems such as urban wind energy harvesting, distributed energy systems, and educational and research equipment. Therefore, considering that the structural size of FDM 3D printed structures is usually limited by the printing platform, if used for large-size wind turbines, a modular splicing structure or a steering molding / injection molding composite process is required to achieve structural scaling.

[0031] In some implementations, the passive substrate layer 3 includes a paper film. Specifically, in this embodiment, the paper film is 0.3 mm thick and is placed below the strain layer to form a double-layer composite beam structure. That is, after the PLA main vein 1 structure is completed by FDM printing, the paper film is attached to its lower surface by hot pressing, bonding, or co-printing, thereby achieving a double-layer combination and enhancing the structure's ability to control thermally activated deformation. The passive substrate layer 3 is a non-responsive layer in the wind turbine blade composite structure and typically does not have active deformation capabilities, but its presence is crucial for defining the deformation direction, enhancing structural rigidity, and forming a bending-torsional coupling effect.

[0032] In this application, the paper membrane primarily serves to limit the deformation direction and provide structural stability. It withstands relatively low stress, making it suitable for experimental verification or micro-blades. However, if stronger dynamic loads are required in applications, materials with higher tensile modulus can be used as alternatives, such as PET film, PI film (polyimide), or carbon fiber woven fabric. Therefore, in practical engineering applications, material selection should be based on size and load requirements. When the application demands high strength, the passive substrate layer can be replaced by PET or other high-modulus films to ensure overall structural stability.

[0033] The principle mechanism of the passive substrate 3 is that in the blade structure, the strain layer made of PLA attempts to return to its pre-deformation state after thermal activation. However, due to its high material rigidity or lack of shape memory effect, the passive substrate 3 constrains the strain of the strain layer, forming a double-layer composite beam effect. This asymmetric structure will naturally undergo bending and / or torsional deformation after heating.

[0034] In some implementation schemes, although Figure 1 and Figure 2The illustration simply shows the overall planar structure of the blade. However, considering that the initial two-dimensional planar state results in insufficient windward angle, the blade will be unable to actively accept wind pressure to drive its rotation. Therefore, in this embodiment, a pre-stressed arc structure needs to be applied to the main vein and side veins during the actual printing process, and the blade needs to have a slightly upward angle (e.g., 5~10°) in the cold state to ensure basic windward capability. For larger blades, mechanical assistance can be added to start the rotation. A lightweight eccentric starter blade can be installed in the impeller system, or a rotating shaft pulley can be used to assist the rotation, allowing it to rotate slowly initially and then adjust its aerodynamic performance through deformation.

[0035] In some implementations, the preset temperature threshold is 60℃~110℃, such as Figure 3 and Figure 4 As shown, at the activation temperature (60℃~110℃), the strain layer of PLA undergoes strain recovery, propelling the entire blade from a two-dimensional planar shape to a three-dimensional curved and torsional form, with angles ranging from 15° bending to 25° torsion. After thermal activation, the shape remains stable upon natural cooling to room temperature in air; if reheated to the activation temperature, it can return to its original shape. This blade structure requires no traditional electronic control system and is suitable for applications such as micro wind power systems and integrated wind power systems in municipal buildings.

[0036] In this application, thermal activation is primarily based on aerodynamic frictional heating caused by wind speed changes. Higher wind speeds result in stronger fluid boundary layer shear stress and surface eddies, leading to the accumulation of trace amounts of frictional heat on the blade surface. Although the frictional heating is limited, under urban or low-to-medium temperature conditions, the required activation temperature (60-80°C) for the PLA substrate can be achieved through localized surface blackening treatment or solar irradiation. When the combined effect of these two factors exceeds the activation temperature threshold, the material enters a shape memory state switching stage, achieving a morphological change. Therefore, the blade's temperature change mainly depends on boundary layer frictional heat caused by wind speed and radiative heat accumulation under solar irradiation conditions; the superposition of these two factors triggers the thermal activation reaction.

[0037] In some implementation schemes, the blade root mounting section 4 is the structural part connecting the blade to the wind turbine hub, undertaking core functions such as torque transmission, fixed connection, and structural support. It is usually designed as a reinforced area with slots, connection holes, or flanges. This part has high structural rigidity and is generally a solid structure or filled with reinforcing fibers. The surface can be provided with pre-fabricated mounting holes to facilitate matching with the connecting flange bolts of the wind turbine.

[0038] The implementation principle of a sparse structure intelligent deformable wind turbine blade is as follows: Because the complete plant leaf structure has drawbacks such as a large wind-exposed surface area and susceptibility to flutter, this embodiment constructs a sparse structure wind turbine blade using a main vein 1 and spaced-apart lateral veins 2. This not only retains the mechanical properties of plant leaves in terms of load-bearing and deformation but also allows for a reduction in the amount of material used in the blade, thus reducing its weight and cost. The main vein 1 serves as the longitudinal main support, providing the necessary stiffness and stability and suppressing excessive overall bending vibration. The lateral veins 2 enhance local stiffness and guide deformation. Compared to an unsupported, purely flexible structure, the composite support configuration formed by the main vein 1 and lateral veins 2 significantly improves flutter resistance.

[0039] By employing shape memory polymers such as PLA and a sparse, flexible structure consisting of "main vein 1 - side vein 2 + paper film layer," the blades themselves possess deformability. The blades can passively and reversibly undergo bending-torsional coupling deformation triggered by ambient temperature, automatically adjusting their aerodynamic shape to adapt to wind speed changes. When increased wind speed causes the blade temperature to rise to a temperature threshold due to friction or external environmental factors, the blades can effectively reduce the aerodynamic loads acting on them during sudden or excessive wind speed changes through adaptive deformation.

[0040] Compared to a solid structure, the material is mainly concentrated on the main and lateral fins 2, which have high load-bearing efficiency. The areas between the frames are covered by a thin paper membrane, significantly reducing the overall material usage and achieving lightweighting. Lighter blades mean lower moment of inertia, reduced starting torque requirements, and easier start-up at low wind speeds. Since the paper membrane constitutes the complete airfoil surface of the blade, the sparse structure itself does not reduce the effective wind-receiving area. The paper membrane of the passive base layer 3 acts as a structural support, suppressing excessive blade deformation and flutter behavior, thereby maintaining aerodynamic stability while maintaining a certain degree of flexibility.

[0041] Example 2: like Figure 5 As shown, this embodiment is a wind turbine, including the sparse structure intelligent deformable wind turbine blades, hub, main shaft, generator, tower and nacelle described in Embodiment 1. The nacelle is located on the top of the tower, and the main shaft and generator are located inside the nacelle. One end of the main shaft is connected to the hub, and the other end of the main shaft is connected to the generator. The blades are mounted on the hub via the blade root mounting part 4.

[0042] The above are all preferred embodiments of this utility model, and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape and principle of this utility model should be covered within the scope of protection of this utility model.

Claims

1. A smart morphing wind turbine blade of sparse structure, characterized by, include: The strain layer includes a main vein (1) and multiple side veins (2). Multiple side veins (2) are provided on the sides of the main vein (1) at a preset angle. The main vein (1) can provide longitudinal main support. The main vein (1) and multiple side veins (2) are made of shape memory polymer, so that the strain layer can undergo bending-torsion coupling deformation when the preset temperature threshold is reached, so as to adapt to wind speed changes. The passive base layer (3) is located at the bottom of the strain layer and can provide deformation constraints for the main vein (1) and the side vein (2). The passive base layer (3) and the strain layer work together to form a double-layer composite beam structure. The blade root mounting part (4) is located at the blade root end of the strain layer and the passive base layer (3) and is used to connect with the hub of the wind turbine.

2. A smart morphing wind turbine blade of sparse structure according to claim 1, characterized in that: The number of lateral veins (2) is not less than 10. The width of the lateral veins (2) gradually decreases from the leaf root to the leaf tip of the main vein (1). The width of the lateral veins (2) at the leaf root is 10 times the width of the lateral veins (2) at the leaf tip.

3. A smart morphing wind turbine blade of sparse structure according to claim 1, characterized in that: The preset angle γ formed by the intersection of the side of the main vein (1) away from the lateral vein (2) and the axis of the lateral vein (2) is 45°.

4. A smart morphing wind turbine blade of sparse structure according to claim 1, characterized in that: The preset temperature threshold is 60℃~110℃.

5. A smart morphing wind turbine blade of sparse structure according to claim 1, characterized in that: The passive substrate layer (3) includes a paper film.

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