Method for repairing and shape preserving utilization of decommissioned wind turbine blades

Abstract

This invention provides a method for repairing and preserving the shape of retired wind turbine blades, belonging to the field of material recycling. The method includes appearance inspection and analysis, infrared thermography analysis, blade repair, and experimental analysis. If all three analyses are satisfactory, the blade is reused as a shape-preserving recycled blade. If any one fails, the blade is cut and modified according to the application scenario to obtain shape-preserving facilities such as billboards, small houses, bus stops, or shelters. The method provided by this invention prioritizes blade repair and reuse, and secondly considers simple cutting and redesign for reuse, extending the blade material's lifespan by 1-2 years, improving material utilization efficiency, and representing a green and low-cost recycling approach.

Description

Technical Field

[0001] This invention belongs to the field of material recycling, specifically relating to a method for repairing and preserving the shape of retired wind turbine blades. Background Technology

[0002] Wind power generation is a crucial step in building my country's modern energy system. By the end of 2021, my country had over 170,000 wind turbine units, with 2.0-2.9MW units being the most numerous, accounting for 47.3%, and units above 5MW accounting for 4.7%, with an average unit capacity of 2025kW. The blades are the core component of a wind turbine, capturing wind energy and converting it into mechanical and electrical energy. Their high cost accounts for 20%-30% of the total cost of a wind turbine. (The last sentence appears to be incomplete and possibly refers to a specific weight or unit, "10-15 kg·kW".) –1 In terms of blade usage, the cumulative installed blade volume nationwide has exceeded 3.4 million tons.

[0003] When wind turbine generators are decommissioned, the blades are also decommissioned. The recycling and disposal of these decommissioned blades is a significant challenge in wind turbine decommissioning. Currently, the main methods for separating and recycling fiber-reinforced composite materials from waste blades include mechanical, thermal, and chemical methods. However, a green, economical, and scalable recycling technology is still lacking. The main reason for this is that decommissioned blades have strong mechanical properties, making disassembly and crushing difficult, and they lack high-value components, resulting in a mismatch between the input and output of recycling.

[0004] Wind turbine blades are primarily composed of fiber-reinforced composite materials and sandwich materials. Upon decommissioning, the blades may be structurally sound or have localized damage, but their overall mechanical properties generally remain good. Therefore, repairing and reusing the blades can realize the high-value utilization of decommissioned blades. Furthermore, the configuration of wind turbine blades conforms to the basic characteristics of many public facilities and small buildings, and they can generally still be used for decades after decommissioning, making them suitable for conversion into other facilities. Therefore, for decommissioned blades that are severely damaged and have high repair costs, they can be reused while preserving their shape through cutting and modification.

[0005] Patent CN115582411A discloses a method for the resource utilization of retired wind turbine blades. The retired wind turbine blades are processed and combined to produce recyclable products. This includes splitting the entire blade for use as a gentle slope support structure for windbreak and sand fixation; using the middle section of the blade as the main structure for petal-shaped or fish-shaped seats, supplemented by wind turbine blade sheet material as the seat surface; using the circular section at the root as the main structure for shops, cafes, etc.; and using the pointed tip of the blade as a directional marker for road signs, etc. This method provides an idea for the processing and combined utilization of retired wind turbine blades, but it does not provide a method for the repair and utilization of wind turbine blades, and the processing and combined utilization scheme is relatively limited. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for repairing and preserving the shape of retired wind turbine blades, which enables the tiered utilization of retired wind turbine blades and is a simple and economical utilization method.

[0007] This invention is achieved through the following technical solution:

[0008] A method for repairing and preserving the shape of retired wind turbine blades includes appearance inspection and analysis, infrared thermography inspection and analysis, blade repair and test analysis. If the appearance inspection and analysis, infrared thermography inspection and analysis and test analysis are all qualified, the blade is reused as a shape-preserving regenerated blade. If any one of them is unqualified, the blade is cut and modified according to the design of the application scenario to obtain a shape-preserving utilization facility.

[0009] Furthermore, the visual inspection analysis is used to determine the condition of the blades for fracture, cracking, and deformation. If the blade has a main beam fracture, cracks ≥1m, or a length tolerance ≥0.2% of the design length, it is deemed to be unqualified in visual inspection. Cracks are mainly examined in the main beam. The core material at the leading and trailing edges is not a major load-bearing structure, and larger cracks can still be repaired. Changes in blade length are mainly caused by deformation during use. Excessive deformation has a significant impact on the mechanical properties of the blade. Therefore, the length tolerance should be controlled within 0.2% of the design length.

[0010] The infrared thermography analysis is used to determine the presence of cracks, delamination, bubbles, and debonding in the blades. Cracks refer to cracks in the main beam; delamination refers to cracks between layers within the main beam; bubbles refer to bubbles larger than 5mm in diameter inside the main beam and at the bonding point between the main beam and the core material; and debonding refers to the separation between the main beam and the core material. If the total number of cracks, delamination, and bubble defects exceeds 5, the infrared thermography inspection is deemed unqualified. An excessive number of cracks, delamination, and bubble defects requires extensive repairs, which may sever the original fibers within the main beam, affecting overall mechanical properties. Therefore, the total number of defects must be controlled to ≤ 5.

[0011] Furthermore, the repair involves fixing blade cracks, delamination, bubbles, and debonding defects. The crack and delamination repair method includes cutting a square groove along the crack and delamination direction to remove the cracked and delaminated portions; smoothing the square groove and cleaning it with acetone; laying reinforcing fiber cloth in the square groove; preparing a polymer solution and pouring it into the square groove; removing air bubbles from the polymer solution by extrusion; laying reinforcing fiber cloth and pouring polymer solution in the same manner, removing air bubbles, with the reinforcing fiber cloth spaced 3-6 mm apart, until the square groove is filled; further polishing the surface and applying a blade surface coating to complete the crack and delamination repair.

[0012] The bubble repair method involves drilling a 3-5mm diameter hole at the bubble location, cleaning it with acetone, creating a vacuum at the hole, mixing a polymer solution with a 3-5mm long reinforcing fiber, injecting the mixture into the bubble location, and filling the hole to complete the bubble repair. The repair process for cracks, delamination, and bubbles should minimize cutting of existing fibers, and the repaired area should be supplemented with blade coating. Repairs to blade coatings and lightning protection systems should also be considered within the scope of the repair.

[0013] The debonding repair method involves injecting fiberglass repair adhesive into the debonding area and removing air bubbles from the adhesive by squeezing to complete the repair of the debonding defect. The debonding usually occurs inside the blade, and the repair process should not involve drilling holes from the outside of the blade to inject fiberglass repair adhesive. Instead, it is necessary to enter the inside of the blade, find the debonding area, and inject adhesive for repair. Therefore, this work can be carried out by robots or manually.

[0014] The polymer solution is one of epoxy resin, unsaturated polyester resin, and vinyl ester resin solution; the reinforcing fiber is one or two of glass fiber and carbon fiber.

[0015] Furthermore, the test analysis involves conducting natural frequency testing, static testing, and fatigue testing on the repaired blade. If the deviation of the natural frequency test result from the original blade's initial design value does not exceed ±2% and is less than ±5% of the unit's excitation frequency harmonic, and the deviation of the static test load and fatigue test results from the original blade's initial design value does not exceed ±5%, then the test analysis is deemed qualified, and the qualified repaired blade is a conformal regeneration blade.

[0016] Furthermore, the defective blades are cut using one of water jet cutting, laser cutting, and saw blade cutting, including cutting the blade tip 5-25m, cutting the blade root cylindrical section 2-10m, cutting from the blade root to the middle of the blade 5-25m, and cutting the middle of the blade 5-25m.

[0017] Furthermore, given the high level of public interest and curiosity surrounding wind power, repurposed wind turbine blades can be transformed into various public facilities and buildings, placed in densely populated urban areas and along roadsides. This not only represents a resource-based approach to the green economy of retired blades but also offers aesthetic appeal and effectively disseminates knowledge about wind power. Blade transformation includes converting 5-25m long blade tips into billboards erected along roadsides and in public places, with advertising slogans and graphics painted on both sides of the blade; converting 2-10m long cylindrical blade roots into small houses with doors and windows, either vertically or horizontally; converting the 5-25m long blade roots down to the bottom of the blade into small houses, with the top converted into billboards; and cutting a 5-25m long blade in half to obtain two halves, which can then be converted into bus stops or shelters. Based on the excellent properties of the blade materials, facilities converted from retired blades can extend the blade material's lifespan by 1-2 years, resulting in a service life of 20-40 years.

[0018] Beneficial technical effects of the present invention:

[0019] (1) The method of the present invention realizes the cascade utilization of retired wind turbine blades, which is a green and low-cost reuse approach;

[0020] (2) The method of the present invention first considers the repair and reuse of the blade, and secondly considers the simple cutting and redesign of the blade for reuse, which can extend the blade material by 1-2 life cycles and improve the utilization efficiency of the material.

[0021] (3) The method for preserving the shape of retired wind turbine blades provided by the present invention presents wind turbine blades to the public at close range, which has good aesthetic appeal and at the same time has good dissemination significance for knowledge of wind power generation. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating a method for repairing and preserving the shape of decommissioned wind turbine blades according to an embodiment of the present invention.

[0023] Figure 2 This is an illustrative diagram showing the tip, middle, and root portions of a decommissioned wind turbine blade in an embodiment of the present invention.

[0024] Figure 3 This is a cross-sectional view of the blade during decommissioning in an embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram illustrating the conversion of the tip of a decommissioned wind turbine blade into an advertising billboard in an embodiment of the present invention.

[0026] Figure 5 This is a schematic diagram illustrating how the roots of decommissioned wind turbine blades can be converted into small houses in a vertical or horizontal orientation, according to an embodiment of the present invention.

[0027] Figure 6 This is a schematic diagram illustrating the transformation of the leaf root to leaf middle component at the bottom into a small house and the top into an advertising board in an embodiment of the present invention.

[0028] Figure 7 This is a schematic diagram of a leaf being cut into two lobes and then transformed into a bus stop or a pergola in an embodiment of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0030] Conversely, this invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of the invention as defined in the claims. Furthermore, to provide a better understanding of the invention, certain specific details are described in detail below. However, those skilled in the art will fully understand the invention even without these detailed descriptions.

[0031] Implementation Case 1

[0032] Repairing a 10-year-old wind turbine blade in Northwest China was carried out. Visual inspection revealed no main beam fractures or cracks ≥1m in length, and the deformation length tolerance was less than 0.2% of the design length. Infrared thermography analysis of cracks, delamination, bubbles, and debonding revealed three cracks ≤0.5m in length and one delamination site on the main beam. Square grooves were cut along the crack and delamination directions to remove the cracks and delamination. The grooves were smoothed and cleaned with acetone. Reinforcing fiber cloth was laid in the grooves, and a polymer solution was prepared and poured into them. Air bubbles in the polymer solution were removed by extrusion. The same process of laying reinforcing fiber cloth and pouring polymer solution was repeated, with 3mm intervals between reinforcing fiber cloths, until the grooves were completely filled. The surface was further polished and a blade surface coating was applied, completing the repair of the cracks and delamination. Further analysis of the blades was conducted using natural frequency testing, static testing, and fatigue testing. The deviation of the natural frequency test results from the original blade's initial design value was ±2%, which is ±20% of the excitation frequency of the turbine. The deviations of the static test load and fatigue test results from the original blade's initial design value were ±5%. Based on this, the repaired blades can be reused for wind turbine power generation.

[0033] Implementation Case 2

[0034] Repairing a 15-year-old wind turbine blade was performed. Visual inspection revealed no main beam fractures or cracks ≥1m in length, and the deformation length tolerance was less than 0.2% of the design length. Infrared thermography analysis of cracks, delamination, bubbles, and debonding revealed one crack ≤0.2m in length, two instances of delamination, and one 12mm diameter bubble inside the main beam. Square grooves were cut along the crack and delamination directions to remove the cracks and delamination. The grooves were smoothed and cleaned with acetone. Reinforcing fiber cloth was laid in the grooves, and a polymer solution was prepared and poured into them. Air bubbles in the polymer solution were removed by extrusion. The same process of laying reinforcing fiber cloth and pouring polymer solution was repeated, with 4mm intervals between reinforcing fiber cloths, until the grooves were completely filled. The surface was further polished and a blade surface coating was applied, completing the repair of the cracks and delamination. A 3mm diameter hole was drilled into the bubble, cleaned with acetone, and a vacuum was created at the hole. A polymer solution mixed with a 5mm long reinforcing fiber was then injected into the bubble, filling the hole completely, thus completing the bubble repair. Further analysis of the blade's natural frequency, static load, and fatigue tests revealed that the natural frequency test results deviated from the original blade's initial design value by ±1.5%, and were ±15% of the turbine's excitation frequency harmonics. The static load and fatigue test results also deviated from the original blade's initial design values ​​by ±4%. It was determined that the repaired blade could be reused for wind turbine power generation.

[0035] Implementation Case 3

[0036] Repairing a 15-year-old wind turbine blade was performed. Visual inspection revealed no main beam fractures or cracks ≥1m in length, and the deformation length tolerance was less than 0.2% of the design length. Infrared thermography analysis of cracks, delamination, bubbles, and debonding revealed one crack ≤0.3m in length on the main beam, one 10mm diameter bubble in the bond between the main beam and core material, and one point of debonding between the main beam and core material. A square groove was cut along the crack direction to remove the cracked portion. The groove was smoothed and cleaned with acetone. Reinforcing fiber cloth was laid in the groove, and a polymer solution was prepared and poured into it. Air bubbles in the polymer solution were removed by extrusion. The same process of laying reinforcing fiber cloth and pouring polymer solution was repeated, with 4mm intervals between reinforcing fiber cloths, until the groove was completely filled. The surface was further polished and a blade surface coating was applied, completing the crack repair. A 4mm diameter hole was drilled at the air bubble location, cleaned with acetone, and a vacuum was created at the hole. A polymer solution mixed with 3mm long reinforcing fibers was then injected into the air bubble, filling the hole completely, thus repairing the air bubble. Fiberglass repair adhesive was injected into the debonded area, and air bubbles were removed from the adhesive by extrusion, completing the repair of the debonding defect. Further analysis of the blade's natural frequency, static load, and fatigue tests was conducted. The natural frequency test results deviated from the original blade's initial design value by ±1%, and were ±10% of the turbine's excitation frequency harmonics. The static load and fatigue test results deviated from the original blade's initial design values ​​by ±3%. It was determined that the repaired blade could be reused for wind turbine power generation.

[0037] Implementation Case 4

[0038] Repairing a wind turbine blade that had been in use for 18 years was carried out. Visual inspection revealed no main beam fractures or cracks ≥1m in length, and the deformation length tolerance was less than 0.2% of the design length. Infrared thermography analysis of cracks, delamination, bubbles, and debonding revealed one crack ≤0.9m in length on the main beam, one delamination within the main beam, one 15mm diameter bubble at the bond between the main beam and core material, and one debonding point between the main beam and core material. Further repairs were performed. Square grooves were cut along the crack and delamination directions to remove the cracks and delamination. The grooves were smoothed and cleaned with acetone. Reinforcing fiber cloth was laid in the grooves, and a polymer solution was prepared and poured into the grooves. Air bubbles in the polymer solution were removed by extrusion. The same process of laying reinforcing fiber cloth and pouring polymer solution was repeated, with 5mm intervals between reinforcing fiber cloths, until the grooves were filled. The surface was further polished and a blade surface coating was applied, completing the repair of the cracks and delamination. A 5mm diameter hole was drilled at the air bubble location, cleaned with acetone, and a vacuum was created at the hole. A polymer solution mixed with 4mm long reinforcing fibers was then injected into the air bubble, filling the hole completely, thus repairing the air bubble. Fiberglass repair adhesive was injected into the debonded area, and air bubbles were removed from the adhesive by extrusion, completing the repair of the debonding defect. Further analysis of the blade's natural frequency, static load, and fatigue tests revealed that the natural frequency test results deviated from the original blade's initial design value by ±0.5%, and were ±6% of the turbine's excitation frequency harmonics. The static load and fatigue test results also deviated from the original blade's initial design values ​​by ±4.5%. It was determined that the repaired blade could be reused for wind turbine power generation.

[0039] Implementation Case 5

[0040] Repairing a 20-year-old wind turbine blade was undertaken. Visual inspection revealed a fractured main beam, necessitating its shape-preserving reuse. Waterjet cutting was used to cut 5m from the blade tip, 2m from the blade root cylindrical section, 5m from the blade root to the middle section, and 18m from the middle section. The blade tip was transformed into an advertising billboard erected along the roadside, with advertising slogans and graphics painted on both sides. The blade root cylindrical section was vertically transformed into a small house with doors and windows. The bottom of the section from the blade root to the middle section was transformed into a small house, and the top into an advertising billboard. The middle section was cut open to obtain two blade halves, which were then converted into bus stops.

[0041] Implementation Case 6

[0042] Repairing a 20-year-old wind turbine blade was undertaken. Visual inspection revealed a main beam crack ≥1m deep, necessitating shape preservation. Waterjet cutting was used to cut 10m from the blade tip, 4m from the blade root cylindrical section, and 10m from the blade root to the middle section. The middle section was then divided into three 15m long components. The blade tip was transformed into an advertising billboard, erected in a plaza in front of a shopping mall, with advertising slogans and graphics painted on both sides. The blade root cylindrical section was vertically transformed into a small house with doors and windows. The bottom of the blade root to middle section was transformed into a small house, and the top into an advertising billboard. The middle section was cut open to obtain two blade halves, each transformed into a pergola.

[0043] Implementation Case 7

[0044] Repairing a 20-year-old wind turbine blade: Visual inspection revealed deformation in the blade with a main beam length tolerance ≥ 0.2% of the design length. Therefore, the blade was reused while preserving its shape. Laser cutting was used to cut a 15m section from the blade tip, a 6m section from the blade root cylindrical section, and several 20m long sections from the blade midsection. The blade tip was transformed into an advertising billboard, erected along the roadside, with advertising slogans and graphics painted on both sides. The blade root cylindrical section was transformed into a small house with doors and windows, laid horizontally. The bottom of the blade root to midsection section was transformed into a small house, and the top into an advertising billboard. The midsection was cut open to obtain two halves, which were then transformed into bus stops.

[0045] Implementation Case 8

[0046] Repairing a 20-year-old wind turbine blade was undertaken. Visual inspection revealed a fractured main beam, necessitating its shape-preserving reuse. A 20m section was cut from the blade tip, an 8m section from the blade root cylindrical section, and several 15m long components were cut from the middle section. The blade tip was transformed into an advertising billboard, erected in a public place, with advertising slogans and graphics painted on both sides. The blade root cylindrical section was transformed into a small house with doors and windows, laid horizontally. The bottom of the components from the blade root to the middle section was transformed into a small house, and the top into an advertising billboard. The middle section was cut open to obtain two halves, which were then converted into bus stops.

[0047] Implementation Case 9

[0048] Repairing a 20-year-old wind turbine blade was undertaken. Visual inspection revealed a main beam crack ≥1m, necessitating shape preservation for reuse. Laser cutting was used to cut a 25m section from the blade tip, a 10m section from the blade root cylindrical section, and several 5m long components from the blade midsection. The blade tip was transformed into an advertising billboard, erected in a public place, with advertising slogans and graphics painted on both sides. The blade root cylindrical section was transformed into a small house with doors and windows, laid horizontally. The bottom of the components from the blade root to the midsection was transformed into a small house, and the top into an advertising billboard. The midsection was cut open to obtain two blade halves, each transformed into a pergola.

[0049] Implementation Case 10

[0050] Repairing a 20-year-old wind turbine blade was undertaken. Visual inspection revealed deformation with the main beam length tolerance exceeding 0.2% of the design length. Therefore, the blade was reused while preserving its shape. Laser cutting was used to cut a 20m section from the blade tip, a 2m section from the blade root cylindrical section, and a 25m section from the blade root to the middle. The middle section was then cut into several 8m long components. The blade tip was transformed into an advertising billboard erected along the roadside, with advertising slogans and graphics painted on both sides. The blade root cylindrical section was vertically transformed into a small house with doors and windows. The bottom of the blade root to middle section was transformed into a small house, and the top into an advertising billboard. The middle section was cut open to obtain two halves, which were then converted into bus stops.

[0051] Implementation Case 11

[0052] Repair was carried out on a wind turbine blade that had been in use for 18 years. Visual inspection revealed no main beam fractures or cracks ≥1m in length, and the deformation length tolerance was less than 0.2% of the design length. Infrared thermography analysis of cracks, delamination, bubbles, and debonding revealed five cracks ≤0.6m in length on the main beam. Further repair was performed on these cracks. A square groove was cut along the crack direction to remove the cracked portion. The groove was then smoothed and cleaned with acetone. Reinforcing fiber cloth was laid in the groove, and a polymer solution was prepared and poured into it. Air bubbles in the polymer solution were removed by extrusion. The same process was repeated, with 5mm intervals between reinforcing fiber cloths, until the groove was completely filled. The surface was further polished and a coating was applied, completing the crack repair. Further analysis of the blade's natural frequency, static load, and fatigue tests was conducted. The natural frequency test results deviated from the original blade's initial design value by ±4%. It was determined that the repaired blades could not be reused for wind turbine power generation, so they were preserved for structural use. Laser cutting was used to cut 20m from the blade tip, 2m from the blade root cylindrical section, and 25m from the blade root to the middle section. The middle section was then cut into several 8m long components. The blade tip was transformed into a billboard erected along the roadside, with advertising slogans and graphics painted on both sides. The blade root cylindrical section was vertically transformed into a small house with doors and windows. The bottom of the blade root to middle section was transformed into a small house, and the top into a billboard. The middle section was cut open to obtain two blade halves, which were then transformed into bus stops.

Claims

1. A method for decommissioned wind turbine blade repair and shape-preserving utilization, characterized in that, This includes appearance inspection and analysis, infrared thermal imaging inspection and analysis, blade repair and test analysis. If the appearance inspection and analysis, infrared thermal imaging inspection and analysis, and test analysis are all qualified, the blades can be reused as shape-preserving regenerated blades. If any item fails to meet the requirements, the blade will be cut and modified according to the design of the application scenario to obtain a shape-preserving component or facility. The visual inspection analysis is to determine the condition of the blades for fracture, cracking, and deformation. If the blades have main beam fracture, cracks ≥1m, or length tolerance ≥0.2% of the design length, the visual inspection is deemed unqualified. The infrared thermal imaging detection and analysis is used to determine the condition of blade cracks, delamination, bubbles, and debonding. Cracks refer to cracks in the main beam, delamination refers to cracks between layers inside the main beam, bubbles refer to bubbles with a diameter greater than 5 mm inside the main beam and at the bonding point between the main beam and the core material, and debonding refers to debonding between the main beam and the core material. If the total number of cracks, delamination, and bubble defects is greater than 5, the infrared thermal imaging detection is deemed unqualified. The repair involves fixing blade cracks, delamination, bubbles, and debonding defects. The crack and delamination repair method includes cutting a square groove along the crack and delamination direction to remove the crack and delamination portions; smoothing the square groove and cleaning it with acetone; laying reinforcing fiber cloth in the square groove; preparing a polymer solution and pouring it into the square groove; removing air bubbles from the polymer solution by extrusion; laying reinforcing fiber cloth and pouring polymer solution in the same way, removing air bubbles, with the reinforcing fiber cloth spaced 3-6 mm apart, until the square groove is filled; further polishing the surface and applying a blade surface coating to complete the crack and delamination repair. One of the bubble repair methods involves drilling a small hole with a diameter of 3-5 mm into the bubble, cleaning it with acetone, creating a vacuum in the hole, mixing the polymer solution with reinforcing fibers with a length of 3-5 mm, injecting the mixture into the bubble, and filling the hole to complete the bubble repair. The debonding repair method involves injecting fiberglass repair adhesive into the debonding area and removing air bubbles from the adhesive by squeezing to complete the repair of the debonding defect. The test analysis involves conducting natural frequency testing, static testing, and fatigue testing on the repaired blade. If the deviation of the natural frequency test result from the original blade's initial design value does not exceed ±2% and is less than ±5% of the unit's excitation frequency harmonic, and the deviation of the static test load and fatigue test results from the original blade's initial design value does not exceed ±5%, then the test analysis is deemed qualified, and the qualified repaired blade is a conformal regeneration blade.

2. The method for repairing and preserving the shape of decommissioned wind turbine blades according to claim 1, characterized in that, The polymer solution is one of epoxy resin, unsaturated polyester resin, and vinyl ester resin solution; the reinforcing fiber is one or two of glass fiber and carbon fiber.

3. The method for repairing and preserving the shape of decommissioned wind turbine blades according to claim 1, characterized in that, The defective blades are cut using one of the following methods: water jet cutting, laser cutting, and saw blade cutting. This includes cutting the blade tip 5-25m, cutting the blade root cylindrical section 2-10m, cutting from the blade root to the middle of the blade 5-25m, and cutting the middle of the blade 5-25m.

4. The method for repairing and preserving the shape of decommissioned wind turbine blades according to claim 1, characterized in that, The blade modification involves transforming the 5-25m long blade tip into an advertising billboard, which is placed along roadsides or in public places, with advertising slogans and graphics painted on both sides of the blade; transforming the 2-10m long blade root cylindrical tube into a small house in a vertical or horizontal direction, with doors and windows; transforming the 5-25m long blade root to the bottom of the blade component into a small house, and the top into an advertising billboard; and cutting the 5-25m long blade in the middle to obtain two blades, which are then transformed into bus stops or pergolas.

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