A wind power blade root layered maintenance method

Abstract

The present application relates to the technical field of wind power blade maintenance, and particularly relates to a wind power blade root layered maintenance method, comprising the following steps: S1: drilling a plurality of through holes penetrating the root body from the outside of the root body through the glass steel skin, the internal reinforcing structure to the inside of the root body; S2: injecting adhesive into the layered gap of the root body; S3: respectively attaching conformal steel plates to the outside and the inside of the root body, the steel plate on the outside of the root body being an outside steel plate, and the steel plate on the inside of the root body being an inside steel plate; S4: sequentially passing fastening bolts through the outside steel plate, the through hole and the inside steel plate and fastening, so that the two steel plates clamp the root body. The maintenance method in the present application can directly perform maintenance operation on the tower, reduces hoisting cost and operation risk, has high maintenance reliability and strong adaptability.

Description

Technical Field

[0001] This invention relates to the field of wind turbine blade maintenance technology, and specifically provides a method for layered maintenance of wind turbine blade roots. Background Technology

[0002] Wind turbine blades are the core energy-harvesting components of wind turbine generators. The integrity and reliability of their structure directly affect the operating efficiency and safety of the unit. As the key part connecting the blade and the hub, the blade root body is subjected to complex alternating loads over a long period of time, making it prone to major failures such as delamination damage. Traditional methods for handling delamination of the blade root body mainly include complete scrapping or hoisting it off the tower for repair. The former leads to component waste and increased costs, while the latter requires large hoisting equipment to lift the blade off the tower, use an angle grinder to grind away the delaminated skin and blade root body reinforcement layer on the outer / inner side of the blade root body, then clean and grind the delamination interface on the embedded parts of the blade root body to create a rough surface, and finally restore the skin and blade root body reinforcement layer. This process is time-consuming and costly, significantly increasing the operating costs of wind power generation and causing power generation losses.

[0003] In recent years, the following documents have addressed solutions for strengthening or repairing the blade root structure: 1) Patent document with publication number "CN222731672U", entitled "A Segmented Connection Structure for the Blade Root of a Wind Turbine Blade", optimizes the connection method through segmented design, but does not address online repair methods for delamination damage, nor does it propose repair processes for blade roots that have already delaminated; 2) Patent document with publication number "CN118438699B", entitled "A Processing Method for the Blade Root Structure of a Wind Turbine Blade", mainly focuses on the blade root manufacturing process. Although it includes some structural optimization, it does not provide repair methods for blades already in use that have delamination, especially lacking on-site repair solutions when the blade is not removed from the tower; 3) Patent document with publication number "CN220302249U", entitled "A Segmented Connection Structure for the Blade Root of a Wind Turbine Blade", focuses primarily on the design of the connection form, without addressing the specific processes and load-bearing mechanisms for delamination repair.

[0004] Of the aforementioned solutions, the closest is the blade root machining method disclosed in Reference Document 2. However, this solution primarily focuses on the manufacturing process and does not address the maintenance issues arising from blade delamination during operation. Furthermore, it does not involve the technical concept of injecting adhesive into the delamination gaps and achieving multi-dimensional load transfer through clamping steel plates. Therefore, designing a solution for rapid, reliable, and low-cost repair of blade root delamination without shutting down the wind turbine or with only a short shutdown is an urgent problem to be solved. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for layered maintenance of wind turbine blade roots, which is simple to operate, highly reliable, can suppress layer expansion, and enables blade maintenance without removing the blade from the tower.

[0006] The present invention provides a method for layered maintenance of wind turbine blade roots, comprising the following steps: S1: Drill multiple through holes through the blade body in the UD rod region of the blade body; S2: Inject adhesive into the interlayered gaps of the leaf basal body; S3: Conformal steel plates are attached to the outer and inner sides of the blade body respectively. The steel plate on the outer side of the blade body is called the outer steel plate, and the steel plate on the inner side of the blade body is called the inner steel plate. S4: Use fastening bolts to pass through the outer steel plate, through hole and inner steel plate in sequence and tighten them so that the two steel plates clamp the blade body.

[0007] Furthermore, in S1, the through hole extends from the outside of the blade body through the fiberglass skin, the UD rod area, the wedge strip, and down to the inside of the blade body.

[0008] Furthermore, in S2, an adhesive is injected into the gaps between the layers of the blade body using a positive pressure conveying method; the adhesive is an epoxy resin structural adhesive.

[0009] Furthermore, in S2, before injecting the adhesive, the gaps between the layers need to be cleaned and the surface activated.

[0010] Furthermore, in S2, when cleaning and surface activating the delamination gaps, a cleaning solvent is injected through drilling and the delamination gaps to remove contaminants and aged adhesive layers within the delamination interface. Then, an air gun is used to blow dry the mixture, followed by the injection of a surface activator.

[0011] Furthermore, when injecting the adhesive in S2, a pneumatic injection device is used to inject the epoxy resin structural adhesive into the layer gap through the injection nozzle from the outer hole; until the adhesive overflows evenly from the inner hole, at which point the gap is fully filled.

[0012] Furthermore, in S3, the shape of the conformal steel plate is matched with the outer contour of the blade body, and the conformal steel plate extends to the outside of the layered area of ​​the blade body, covering the outside of the blade body; bolt holes are pre-drilled on the conformal steel plate, and the fastening bolts in S4 pass through the bolt holes.

[0013] Furthermore, in S4, clamping is achieved by applying a preload to the fastening bolts; the preload applied to the fastening bolts results in a friction coefficient of 0.2-0.3 between the conformal steel plate and the blade body surface.

[0014] Furthermore, the fastening bolts are arranged in an array along the circumferential and chordal directions of the blade body.

[0015] Furthermore, an elastic sealant layer is applied between the inner surface of the conformal steel plate and the outer surface of the blade body to form an anti-corrosion sealant layer between the conformal steel plate and the blade body.

[0016] Compared with the prior art, the present invention can achieve the following beneficial effects: 1. This solution enables online maintenance of blades without removing them from the tower. Maintenance work can be carried out directly on the tower without lifting the blades off the tower, which greatly reduces lifting costs and operational risks, reduces maintenance time and wind turbine downtime losses, and improves the operational economic efficiency of wind farms. Compared with traditional scrapping or tower removal maintenance methods, it significantly reduces material replacement costs, lifting costs and power generation losses, and significantly reduces operation and maintenance costs throughout the entire life cycle.

[0017] 2. This solution restores the bonding strength of the interface by injecting adhesive into the gaps between the layers of the blade body. At the same time, by using fastening bolts to clamp the steel plates on both sides to the blade body, a composite load-bearing system is formed by the synergistic effect of the adhesive force, the friction between the steel plates and the fiberglass of the blade body, and the shear bearing capacity of the bolts. This load-bearing system can effectively transfer the axial and chordal loads of the blade body, ensuring the strength, stiffness and overall load-bearing capacity of the blade body after maintenance. The structure is simple and the maintenance reliability is high.

[0018] 3. The double-sided steel plate clamping structure in this solution can not only enhance the local rigidity of the blade body, but also form a mechanical constraint on the existing delamination area, which can delay or even prevent the further expansion of delamination defects, thereby extending the service life of the blade and improving the long-term operational reliability of wind power equipment. Moreover, this process method is applicable to the delamination maintenance of various blade body structure forms and has good on-site operability and promotion value. Attached Figure Description

[0019] Figure 1 This is a front view (overall structural schematic diagram) of the leaf root layered maintenance method provided in an embodiment of the present invention. Figure 2 This is a front view (partial structural schematic diagram) of the leaf root layered maintenance method provided in an embodiment of the present invention. Figure 3 This is a cross-sectional schematic diagram (side view) provided according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the inner steel plate provided according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the outer steel plate provided according to an embodiment of the present invention.

[0020] The reference numerals in the attached drawings include: UD rod area 1, outer steel plate 2, inner steel plate 3, fastening bolt 4, fiberglass skin 5, blade body 6, bolt hole 7, wedge strip 8. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the following description is provided in conjunction with the appendix. Figure 1-5 The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and do not constitute a limitation thereof.

[0022] A method for layered maintenance of wind turbine blade roots includes the following steps: S1: Multiple through holes are drilled through the UD rod region 1 of the blade base 6, extending from the outside of the blade base 6 through the fiberglass skin 5, the UD rod region 1, and the wedge-shaped strip 8, down to the inside of the blade base 6. Figures 1-3 As shown, the blade root body 6 includes, from the outside to the inside, an outer fiberglass skin 5, a UD rod region 1 (containing a unidirectional fiber reinforcement layer), and an inner wedge-shaped strip 8. When drilling, the blade root region must first be scanned using non-destructive testing equipment to accurately define the boundaries, depth, and main extension direction of the delamination damage. Based on the test results, drilling should be carried out in the UD rod region 1 where the damage is most significant or the load is critical. The drilling path should pass through the delamination interface as much as possible to ensure that the subsequently injected adhesive can effectively cover the main damaged area. The drilling position should avoid the extreme stress zone of the main load path of the blade root.

[0023] S2: Inject adhesive into the gaps between the layers of the blade body 6. High-viscosity adhesive is injected into the gaps between the layers of the blade body 6 using a positive pressure delivery method. The high-viscosity adhesive is an epoxy resin structural adhesive. After curing, the high-viscosity adhesive forms a continuous adhesive layer, which can restore the load transfer function of the layer interface.

[0024] Before injecting the high-viscosity adhesive, the delamination gaps need to be cleaned and the surface activated. This pretreatment ensures that the adhesive forms a high-strength, durable interface with the old composite matrix. Specifically, cleaning solvent is injected through drilling and delamination gaps to remove contaminants and aged adhesive layers in the delamination interface, followed by air drying with an air gun, and then the surface activator is injected.

[0025] The cleaning solvent is a composite cleaning agent with high volatility, moderate dissolving ability and no corrosion to the composite material. The through hole prepared in S1 is used as the injection and discharge channel. The cleaning solvent is injected into the layer gap through the selected one-sided through hole by low pressure injection or pressurized spray. The solvent flows and wets in the gap, dissolves and removes grease, release agent residue, moisture, dust and aged and failed original adhesive layer on the interface.

[0026] When injecting high-viscosity adhesive, use a pneumatic injection device to inject the two-component epoxy structural adhesive into the layer gap through the injection nozzle from the outer hole until the adhesive overflows evenly from the inner hole. This indicates that the gap has been fully filled. After ensuring that the gap is fully filled, stop the injection, quickly remove the injection nozzle, and immediately use temporary sealing parts to seal the inner outlet and the outer injection port to prevent the adhesive from flowing back or dripping before curing. Also, clean up any excess adhesive adhering to the blade surface and around the through hole.

[0027] An elastic sealant layer is applied between the inner surface of the conformal steel plate and the outer surface of the blade root body 6 to form an anti-corrosion sealing layer between the conformal steel plate and the blade root body 6. The anti-corrosion sealing layer can prevent environmental media such as moisture and salt spray from penetrating into the gap between the conformal steel plate and the blade root body 6, and is especially suitable for harsh environments such as marine and high humidity. At the same time, the anti-corrosion sealing layer can evenly transmit clamping pressure and buffer local stress concentration, avoid the edge of the conformal steel plate from causing pressure damage to the blade root composite material, and make up for the micro-unevenness between the surfaces of the conformal steel plate and the blade root body 6, ensuring a tight fit. It can also absorb some vibration energy, which is beneficial to improving the fatigue life of the structure.

[0028] S3: Conformal steel plates are attached to the outer and inner sides of the blade body 6, respectively. The steel plate on the outer side of the blade body 6 is called outer steel plate 2, and the steel plate on the inner side of the blade body 6 is called inner steel plate 3. The shape of the conformal steel plate matches the outer contour of the blade body 6, and the conformal steel plate extends to the outer side of the layered area of ​​the blade body 6. The conformal steel plate covers the outer side of the blade body 6. Bolt holes 7 are pre-drilled on the conformal steel plate. The fastening bolts 4 in S4 pass through the bolt holes 7. The conformal steel plate must completely cover the layered area of ​​the blade body 6 and extend outward by a certain safety distance. It is generally recommended to extend it at least 50mm to 100mm beyond the layer boundary to provide sufficient bearing surface and stress diffusion zone.

[0029] The outer steel plate 2 and the inner steel plate 3 are made of structural steel with high strength, good toughness and fatigue resistance, such as Q345B, Q355B or alloy steel with equivalent performance. For offshore or highly corrosive environments, stainless steel, such as 316L, can be used, or heavy-duty anti-corrosion coating treatment, such as hot-dip galvanizing or spraying heavy-duty anti-corrosion coating, can be applied. The thickness of the outer steel plate 2 and the inner steel plate 3 is determined according to the blade size, load level and safety factor.

[0030] S4: Fastening bolts 4 are passed through the outer steel plate 2, the through hole, and the inner steel plate 3 in sequence and tightened to clamp the blade body 6 between the two steel plates. The clamping is achieved by applying a preload to the fastening bolts 4. The preload applied to the fastening bolts 4 makes the coefficient of friction between the conformal steel plate and the surface of the blade body 6 0.2-0.3, which can transfer most of the in-plane load through friction. The fastening bolts 4 are arranged in an array in the circumferential and chordal directions of the blade body 6 to optimize the uniformity of load transfer. The fastening bolts 4 themselves can bear shear loads, especially under impact load conditions, providing safety redundancy.

[0031] Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0032] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for layered maintenance of wind turbine blade roots, characterized in that, Includes the following steps: S1: Drill multiple through holes through the leaf root body (6) in the UD rod region (1) of the leaf root body (6); S2: Inject adhesive into the interlayer gaps of the leaf root body (6); S3: Conformal steel plates are attached to the outer and inner sides of the leaf body (6), respectively. The steel plate on the outer side of the leaf body (6) is called the outer steel plate (2), and the steel plate on the inner side of the leaf body (6) is called the inner steel plate (3). S4: Use fastening bolts (4) to pass through the outer steel plate (2), through hole and inner steel plate (3) in sequence and fasten them so that the two steel plates clamp the blade body (6).

2. The method for layered maintenance of wind turbine blade roots according to claim 1, characterized in that, In S1, the through hole extends from the outside of the blade body (6) through the fiberglass skin (5), the UD rod area (1), and the wedge strip (8) to the inside of the blade body (6).

3. The method for layered maintenance of wind turbine blade roots according to claim 1, characterized in that, In S2, adhesive is injected into the gap between the layers of the blade body (6) using a positive pressure conveying method; the adhesive is epoxy resin structural adhesive.

4. The method for layered maintenance of wind turbine blade roots according to claim 3, characterized in that, Before injecting the adhesive in S2, the gaps between the layers need to be cleaned and the surface activated.

5. The method for layered maintenance of wind turbine blade roots according to claim 4, characterized in that, In S2, when cleaning and surface activating the delamination gaps, cleaning solvent is injected through drilling and delamination gaps to remove contaminants and aged adhesive layers within the delamination interface. Then, the surface is dried with an air gun and subsequently injected with a surface activator.

6. The method for layered maintenance of wind turbine blade roots according to claim 3, characterized in that, When injecting adhesive into S2, a pneumatic injection device is used to inject epoxy resin structural adhesive into the layer gap through the injection nozzle from the outer hole; until the adhesive overflows evenly from the inner hole, at which point the gap is fully filled.

7. The method for layered maintenance of wind turbine blade roots according to claim 1, characterized in that, In S3, the shape of the conformal steel plate is matched with the outer contour of the blade body (6), and the conformal steel plate extends to the outside of the layered area of ​​the blade body (6), and the conformal steel plate covers the outside of the blade body (6); bolt holes (7) are pre-drilled on the conformal steel plate, and the fastening bolts (4) in S4 pass through the bolt holes (7).

8. The method for layered maintenance of wind turbine blade roots according to claim 1, characterized in that, In S4, clamping is achieved by applying a preload to the fastening bolt (4); the preload applied to the fastening bolt (4) makes the friction coefficient between the conformal steel plate and the surface of the blade body (6) 0.2-0.

3.

9. The method for layered maintenance of wind turbine blade roots according to claim 8, characterized in that, The fastening bolts (4) are arranged in an array in the circumferential and chordal directions of the blade body (6).

10. The method for layered maintenance of wind turbine blade roots according to claim 1, characterized in that, An elastic sealant layer is applied between the inner surface of the conformal steel plate and the outer surface of the blade body (6) to form a corrosion-resistant sealant layer between the conformal steel plate and the blade body (6).

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