Integrated forming method of variable cross-section composite fan blade

Abstract

The invention relates to the technical field of rail transit, in particular to an integrated forming method for a variable-cross-section composite fan blade, and the integrated forming method for the variable-cross-section composite fan blade is characterized in that the variable-cross-section fan blade is provided with a compression molding die which comprises an upper die, a lower die, a base movable block and a base pressurizing block; the upper die and the lower die are vertically distributed up and down, the product material sheets are respectively paved in the die cavity surfaces of the upper die and the lower die, and the die cavities of the upper die and the lower die are respectively provided with a root area, a base area and a blade area. The one-way carbon fiber prepreg is used as the main raw material, the fan blade is integrally formed through the compression molding technology, the technology is relatively simple and easy to operate, it can be guaranteed that fibers at the root of the blade are continuous, the appearance size of a product is accurate and controllable, the weight consistency is good, the surface is smooth and flat, and the method is suitable for mass production.

Description

Technical Field

[0001] This application relates to the field of rail transit technology, specifically to an integrated molding method for variable cross-section composite material wind turbine blades. Background Technology

[0002] Wind turbine blades provide power during train operation. Currently, most wind turbine blades on freight trains are metal structures, which are heavy and have low kinetic energy conversion rates. To improve kinetic energy conversion rates, reducing the weight of wind turbine blades is imperative, but it is also necessary to maintain the aerodynamic shape and mechanical properties of the blades. To ensure the aerodynamic shape, a compression molding process is used for the mold. Wind turbine blades are also complex surfaces with varying hyperbolic curvature. The smaller the weight difference between each set of blades, the better the balance of the wind turbine blades after installation, the less vibration during operation, and the higher the efficiency. Therefore, the stability and consistency of the product's weight and shape are also very important. Summary of the Invention

[0003] To improve the stability and consistency of the weight and shape of the above products, the present invention provides an integrated molding method for variable cross-section composite material wind turbine blades, which have the advantages of high weight consistency, stable batch production, and excellent performance.

[0004] This invention specifically provides an integrated molding method for variable cross-section composite material wind turbine blades, including a molding die for the variable cross-section wind turbine blades, comprising an upper die, a lower die, a base block, and a base pressure block. The upper die and the lower die are vertically distributed, and the product sheet is respectively laid in the cavity of the upper die and the lower die. The upper die and the lower die cavity are each provided with a root area, a base area, and a blade area.

[0005] Furthermore, the base area is provided with a base movable block and a base pressure block. The base movable block is detachably disposed between the upper mold and the lower mold base area, and the base pressure block is disposed at the rear end of the base movable block.

[0006] Furthermore, the carbon fibers at the root of the variable cross-section composite wind turbine blade are continuous fibers.

[0007] Furthermore, the solid middle part of the variable cross-section composite material wind turbine blade can be a foam sandwich structure.

[0008] Furthermore, product positioning pins are provided at the four corners of the upper end of the lower mold.

[0009] Furthermore, the lower mold has overflow grooves on both the left and right sides of its upper end.

[0010] Furthermore, temperature measuring holes are provided on both sides of the upper front end of the lower mold and both sides of the lower front end of the upper mold.

[0011] Compared with the prior art, the main advantages of the present invention are: The variable cross-section composite material wind turbine blade provided by this invention is integrally molded, with the root fibers at the connection between the blade and the base remaining continuous, fully utilizing the high strength advantage of carbon fiber. The fiber distribution in the base area can reduce cracking of the base during long-term use.

[0012] In this invention, the upper and lower molds are easy to close, the product is accurately positioned, and the fiber at the root of the blade is continuous. When the upper and lower molds are closed, the upper and lower mold cavities press the product on the upper and lower surfaces. The base pressure block can better press the product base by squeezing the base movable block. During pressurization, excess material and gas in the product will flow into the overflow grooves on the left and right sides of the lower mold along with the resin.

[0013] In this invention, each layer of material is drawn according to the curvature and thickness of the blades, ensuring that no manual trimming is required during the product installation process, the product weight is controllable, and the weight of each product is highly consistent.

[0014] In this invention, the carbon fiber at the root of the blade is a continuous fiber, and the root of the blade is the main load-bearing area. Both the 0° and 45° fibers are continuous fibers at the root position, which fully utilizes the strength advantage of carbon fiber.

[0015] In this invention, to prevent product distortion, the product layers are symmetrically laid out. During installation, the upper mold coordinate system is a right-handed coordinate system, and the lower mold coordinate system is a left-handed coordinate system.

[0016] In this invention, the blade cross-section is approximately 150 mm long, with a minimum thickness of approximately 1.98 mm and a maximum thickness of approximately 9.02 mm. The cross-sectional thickness varies considerably. By using a sheet layering design, the thickness can be made uniform while ensuring symmetrical layering, thus reducing distortion caused by internal stress.

[0017] In this invention, to further reduce the weight of the product, the solid middle part can use a foam core knot.

[0018] In this invention, carbon fiber fabric prepreg is used on the surface. Excess prepreg is trimmed off along the mold outline at the mold closing seam, and overlapped at the right-angle bend of the base to ensure the continuity of the overall surface fibers and the clear and beautiful fabric texture.

[0019] In this invention, the fibers around the base at a depth of 5.4mm completely encapsulate the fibers of the base laminate structure, which can prevent the base from cracking or the interlayer from being damaged during use. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the lower mold in the compression molding die for the variable cross-section composite material wind turbine blade provided by the present invention; Figure 2 This is a schematic diagram of the upper mold in the compression molding die for the variable cross-section composite material wind turbine blade provided by the present invention; Figure 3 This is a schematic diagram of the base block in the compression molding die for the variable cross-section composite material wind turbine blade provided by the present invention; Figure 4 This is a schematic diagram of the fiber placement position of the variable cross-section composite material wind turbine blade provided by the present invention.

[0021] Reference numerals used in the above figures: 1. Upper mold; 2. Lower mold; 3. Base movable block; 4. Base pressurizing block; 5. Product positioning pin; 6. Glue overflow groove; 7. Temperature measuring hole. Detailed Implementation

[0022] 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 merely illustrative and not intended to limit the invention.

[0023] The implementation of the present invention will be described in detail below with reference to specific embodiments.

[0024] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this invention, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this invention and simplifying the description, and do not 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, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0025] Reference Figure 1-4 The image shows a preferred embodiment of the present invention.

[0026] An integrated molding method for a variable cross-section composite material wind turbine blade includes a compression molding die for the variable cross-section wind turbine blade, comprising an upper die 1, a lower die 2, a base block 3, and a base pressure block 4. The upper die 1 and the lower die 2 are vertically distributed vertically. Product sheets are respectively laid in the cavity surfaces of the upper die 1 and the lower die 2. The cavities of the upper die 1 and the lower die 2 are each provided with a root area, a base area, and a blade area.

[0027] Before the upper mold 1 and lower mold 2 are closed, the product sheet is laid on the cavity surface of the upper and lower molds respectively to ensure the continuity of the fiber at the root of the blade.

[0028] The base area is provided with a base movable block 3 and a base pressure block 4. The base movable block 3 is detachably set between the base areas of the upper mold 1 and the lower mold 2, and the base pressure block 4 is set at the rear end of the base movable block 3.

[0029] After the upper mold 1 and the lower mold 2 are closed, the base sheet is placed at the base position, and then the base movable block 3 is placed in the corresponding position. The wedge-shaped base pressure block 4 continuously applies pressure to the base movable block 3 to ensure the structural compactness of the base.

[0030] The carbon fiber at the root of the variable cross-section composite wind turbine blade is a continuous fiber.

[0031] The root of the blade is the main load-bearing area, and continuous fibers are provided at the root position for both 0° and 45° fibers, which fully utilizes the strength advantage of carbon fiber.

[0032] The solid middle section of the variable cross-section composite material wind turbine blade can be a foam sandwich structure.

[0033] This facilitates further reduction in product weight.

[0034] Product positioning pins 5 are provided at the four corners of the upper end of the lower mold 2.

[0035] The lower mold 2 has overflow grooves 6 on both the left and right sides of the upper end.

[0036] When the upper mold 1 and the lower mold 2 are closed and pressurized, excess material and gas inside the product will flow into the overflow grooves 6 on the left and right sides of the lower mold 2 along with the resin, thereby ensuring the pneumatic shape and quality of the product.

[0037] Temperature measuring holes 7 are provided on both sides of the upper front end of the lower mold 2 and both sides of the lower front end of the upper mold 1.

[0038] The manufacturing method of the integrated molding method for variable cross-section composite material wind turbine blades provided in this embodiment is as follows: S1. Unfold the blade profile as a whole, and draw each layer of material according to the changes in blade curvature and thickness. The 0° and 45° fibers are kept continuous at the root where the blade and base are connected. The carbon fiber unidirectional prepreg is cut into the material according to the shape of the material using an automatic cutting machine to ensure that no manual trimming is required during the product laying process, the product weight is controllable, and the weight of each product is highly consistent.

[0039] S2. Carbon fiber prepreg is used on the mold surface. Excess prepreg is trimmed off along the mold outline at the mold seam and overlapped at the right angle bend of the base to ensure the continuity of the fiber on the overall surface and the clear and beautiful texture of the fabric.

[0040] S3. Carbon fiber unidirectional prepreg sheets are laid from the blade tip to the base according to the blade profile template. No manual trimming is required during the laying process. During laying, the upper mold 1 coordinate system is a right-handed coordinate system, and the lower mold 2 coordinate system is a left-handed coordinate system. The prepreg for the base is laid separately, pre-compacted at room temperature, and then placed in the base area. After all sheets for the upper and lower molds are laid, the upper and lower molds are closed and placed in a hot press.

[0041] S4. When the temperature inside the mold cavity reaches (110±5)℃, pressurization begins at a pressure of (8-10) MPa. Exhaust is performed at least three times, and the temperature is maintained at (130±5)℃ for (120±10) minutes. During the curing process, the upper and lower mold cavity surfaces apply pressure to the top and bottom surfaces of the product. The base pressure block 4, by squeezing the base movable block 3, can better pressurize the product base. Excess material and gas inside the product will flow with the resin into the overflow grooves on the left and right sides of the lower mold 2.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for integral molding of variable cross-section composite material wind turbine blades, characterized in that, The variable cross section wind turbine blade is provided with a molding die, including an upper die (1), a lower die (2), a base block (3) and a base pressure block (4). The upper die (1) and the lower die (2) are vertically distributed. The product material is respectively laid in the cavity surface of the upper die (1) and the lower die (2). The cavities of the upper die (1) and the lower die (2) are provided with a root area, a base area and a blade area.

2. The integrated molding method for a variable cross-section composite material wind turbine blade according to claim 1, characterized in that, The base area is provided with a base movable block (3) and a base pressure block (4). The base movable block (3) is detachably disposed between the base areas of the upper mold (1) and the lower mold (2). The base pressure block (4) is disposed at the rear end of the base movable block (3).

3. The integrated molding method for a variable cross-section composite material wind turbine blade according to claim 2, characterized in that, The lower mold (2) is provided with product positioning pins (5) at the four corners of its upper end.

4. The integrated molding method for a variable cross-section composite material wind turbine blade according to claim 3, characterized in that, The lower mold (2) has overflow grooves (6) on both the left and right sides of its upper end.

5. The integrated molding method for a variable cross-section composite material wind turbine blade according to claim 4, characterized in that, Temperature measuring holes (7) are provided on both sides of the upper front end of the lower mold (2) and both sides of the lower front end of the upper mold (1).

6. The integrated molding method for a variable cross-section composite material wind turbine blade according to claim 5, characterized in that, The carbon fibers at the root of the variable cross-section composite wind turbine blade are continuous fibers.

7. The integrated molding method for a variable cross-section composite material wind turbine blade according to claim 6, characterized in that, The solid middle part of the variable cross-section composite material wind turbine blade can be a foam sandwich structure.

8. The integrated molding method for a variable cross-section composite material wind turbine blade according to claim 7, the specific method being: S1. Unfold the blade profile as a whole, draw each layer of material according to the changes in blade curvature and thickness. The 0° and 45° fibers are kept continuous at the root where the blade and base are connected. The carbon fiber unidirectional prepreg is cut into the material using an automatic feeder according to the shape of the material. S2. Carbon fiber prepreg is used on the mold surface. The excess prepreg is trimmed off along the mold outline at the mold seam and overlapped at the right-angle bend of the base. S3. Carbon fiber unidirectional prepreg sheets are laid from the blade tip to the base according to the blade profile template. During laying, the upper mold (1) coordinate system is a right-handed coordinate system, and the lower mold (2) coordinate system is a left-handed coordinate system. The prepreg for the base is laid separately, pre-compacted at room temperature, and then placed in the area where the base is located. After all the sheets of the upper and lower molds are laid, the upper and lower molds are closed and placed in a hot press. S4. When the temperature inside the mold cavity rises to (110±5)℃, pressurization begins, with a pressure of (8-10)MPa. Exhaust air at least 3 times and keep warm at (130±5)℃ for (120±10) minutes. During the curing process, the upper and lower mold cavity surfaces apply pressure to the upper and lower surfaces of the product. The base pressure block (4) can better pressurize the product base by squeezing the base movable block (3). Excess material edge and gas inside the product will flow into the overflow grooves (6) on the left and right sides of the lower mold (2) along with the resin.

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