Blade leading edge UD preforming process

Abstract

The invention belongs to the technical field of blade front edge machining, and particularly relates to a blade front edge UD prefabrication forming process which comprises the following steps that S1, a front edge UD prefabrication mold is prepared; s2, front edge UD prefabrication forming: laying a UD cloth layer lower auxiliary material, laying a front edge UD cloth layer, laying a UD cloth layer upper auxiliary material, and performing vacuum infusion and demolding; and S3, the prefabricated front edge UD and the shell are subjected to integrated pouring forming. By means of the method, the defects of offset wrinkles in the laying process of the front edge UD or the defects formed in the pouring process can be eliminated, the failure of the front edge area of the blade is prevented, the anti-fatigue performance of the blade is improved, the structural strength is enhanced, and the product safety is improved.

Description

Technical Field

[0001] This invention belongs to the field of blade leading edge processing technology, specifically relating to a blade leading edge UD preforming process. Background Technology

[0002] The leading edge (UD) is located at the leading edge of the blade. During operation, the leading edge is continuously impacted by airflow, raindrops, dust, etc., making it prone to fatigue damage. The UD material has unidirectionally arranged fibers, which can provide high-strength support along the length of the blade, effectively resisting repeated loads and extending the blade's service life.

[0003] During the shell layup process, the UD fabric layer at the leading edge is laid in staggered layers in both axial and chordal directions on the leading edge region of the cavity. Due to the large curvature of the blade's leading edge region, it is commonly fixed by spraying adhesive and sewing it together with cotton thread. However, during the layup process, the UD fabric layer is prone to slippage and shifting, as well as deformation of the fabric yarn bundles causing wrinkles. This affects the production quality of the blade's leading edge region, increasing quality risks and maintenance costs. After the leading edge UD fabric layer is laid, it is vacuum-cast into the shell. During the casting process, defects such as poor wetting of the UD fabric layer and encapsulation of semi-dry yarns can easily occur. Summary of the Invention

[0004] To address the problems in the prior art, this invention provides a blade leading edge UD prefabrication process, which aims to eliminate offset wrinkles or defects formed during the leading edge UD laying process or the grouting process, prevent failure in the leading edge region of the blade, improve the blade's fatigue resistance, enhance structural strength, and improve product safety.

[0005] The technical problem solved by this invention is achieved by the following technical solution:

[0006] The present invention aims to provide a blade leading edge UD preforming process, comprising the following steps:

[0007] S1: Prepare the leading edge UD preform;

[0008] S2: Leading edge UD prefabrication: including laying the lower auxiliary material of UD fabric layer, laying the leading edge UD fabric layer, laying the upper auxiliary material of UD fabric layer, vacuum injection and demolding;

[0009] S3: The prefabricated leading edge UD is integrally cast with the shell.

[0010] Furthermore, the preparation of the leading edge UD prefabricated mold includes: fabricating the leading edge UD prefabricated mold according to the leading edge UD design parameters of different projects, and matching the mold surface with the main mold.

[0011] Furthermore, the laying of the UD fabric layer under auxiliary materials includes: laying the UD fabric layer under auxiliary materials according to process requirements, and drawing the chordal and axial positioning lines of the fabric layer. The under auxiliary materials include the lower guide net and the release cloth.

[0012] Furthermore, laying the leading edge UD fabric layer includes: laying the UD fabric layer according to the design and process requirements, trimming the fabric layer, and simultaneously confirming the dimensions.

[0013] Furthermore, the process of laying the UD fabric layer auxiliary materials includes: laying the fabric layer auxiliary materials, including the isolation membrane, the upper guide net, and the vacuum bag film. The auxiliary materials are strictly positioned, the vacuum bag film is sealed, the vacuum pump valve is opened, and the vacuum is started. At the same time, the vacuum bag film is adjusted to fit tightly against the flange corners, flow channels, and exhaust vacuum pipes, so that the vacuum bag film is not taut after the vacuum is tightened. At the same time, the sealing strip is pressed along the edge of the mold to make the vacuum bag film fit tightly against the sealing strip and the mold, without air leakage.

[0014] Furthermore, the auxiliary materials for laying the UD fabric layer also include: after the first layer of vacuum bag film is tightened, when the vacuum pump reading is ≤-81Kpa, sealing the second layer of vacuum bag film, and connecting the two layers of vacuum bag film with a guide net or breathable cotton. The guide net or breathable cotton is laid in a Z-shape connecting the front and rear edges and extending from the root of the mold to the tip of the mold.

[0015] Furthermore, the auxiliary materials for laying the UD fabric layer also include: after sealing the two layers of vacuum bag film, inserting a spiral steel wire tube into the glue injection seat. After the connection is completed, when the vacuum gauge reading inside the first layer of vacuum bag film is less than 20 mbar, close the first layer of vacuum pump and the valve of the air extraction pipeline, keep all air extraction ports open, and continue to extract air from the second layer of vacuum bag film to start pressure holding. The pressure holding rule is that the change should not exceed 15 mbar within 10 minutes, which indicates that the vacuum bag film is in good sealing condition and vacuum injection can be carried out.

[0016] Furthermore, vacuum infusion includes: at the start of infusion, the mold is set to 35-50℃, and after infusion, it is adjusted to 65-85℃ until curing for 5-8 hours. After the product surface is cured, the hardness of the flange and the main surface is tested every 5m. The chordal position of the cross section is randomly selected, and the Tg value is measured at the same time. Tg > 70℃ and Shore hardness > 55HD are qualified. At the same time, the cotton quilt on the web plate is lifted, the hot water circulation is turned off, and the temperature of all areas of the product surface drops below 45℃ before demolding.

[0017] Furthermore, the prefabricated leading edge UD is integrally cast with the shell, which includes: placing the prefabricated leading edge UD in the leading edge area of ​​the shell mold, so that it is completely attached to the inner and outer fabric layers of the shell, and eliminating fabric layer displacement and wrinkles in the leading edge UD area.

[0018] This invention discloses a blade leading edge UD prefabrication process. Based on the leading edge UD design parameters for different projects, a leading edge UD prefabrication mold is manufactured. The mold surface matches the main mold. After prefabrication, the mold facilitates on-site operation, improving production efficiency and product quality. Before leading edge UD prefabrication, a production mold is manufactured according to different models and requirements, or different models of the same mold. The mold can be manufactured according to the maximum width of the leading edge UD, improving mold utilization and effectively eliminating defects such as leading edge UD fabric wrinkles, improving blade fatigue resistance, enhancing structural strength, and improving product safety.

[0019] When the leading edge UD is pre-formed, after the auxiliary materials such as the guide net and release cloth under the UD fabric layer are laid and fixed according to the process plan, the leading edge UD fabric layer is laid strictly according to the process and design requirements. After the fabric layer is laid, the inspection requirements such as the start and end positions of the staggered layer are confirmed. After confirming that the subsequent auxiliary materials are laid, vacuum injection is carried out. When the injection begins, the mold is set at 35-50℃. After the injection is completed, it is adjusted to 65-85℃. The temperature adjustment can be adjusted according to the local atmospheric pressure. After curing for 5-8 hours, the product is demolded. After demolding, the product quality is inspected and placed in the storage tooling for later use.

[0020] The leading edge prefabricated UD is integrally cast with the shell. According to the project design and process plan, the leading edge prefabricated UD is placed in the leading edge area of ​​the shell mold, and is completely attached to the inner and outer fabric layers of the shell, eliminating fabric layer displacement and wrinkles in the leading edge UD area, and further improving product quality.

[0021] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0022] 1. The blade leading edge UD prefabrication process of the present invention can eliminate the defects formed by the offset wrinkles or the grouting process during the leading edge UD laying process, prevent the failure of the blade leading edge area, improve the blade fatigue resistance, enhance the structural strength, and improve product safety.

[0023] 2. The leading edge UD prefabrication of this invention can accurately arrange the fiber direction and number of layers according to the stress characteristics of the leading edge, so that the material strength is concentrated in the key stress direction (such as aerodynamic load, centrifugal force direction), avoiding material waste, improving structural efficiency, reducing human laying errors and reducing the amount of adhesive used during the prefabrication process, effectively eliminating human defects such as UD fabric wrinkles, and facilitating quality inspection to ensure the quality status of the prefabricated UD and improve product quality.

[0024] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the specification. Furthermore, in order to make the above contents, objectives, features and advantages of the present invention more obvious and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0025] Figure 1 This is a flow chart of the blade leading edge UD prefabrication process according to the present invention.

[0026] Figure 2 This is a schematic diagram of the leading edge UD preform mold of the present invention.

[0027] Figure 3 This is a schematic diagram of the arrangement of the lower auxiliary materials in the leading edge UD preform of the present invention.

[0028] Figure 4 This is a schematic diagram of the arrangement of auxiliary materials in the leading edge UD preform of the present invention.

[0029] Figure 5 This is a schematic diagram of the vacuum sealing process during the preforming of the leading edge UD of the present invention.

[0030] 1- Leading edge UD preformed mold, 2- Product, 3- Lower guide net, 4- Release cloth, 5- Sealing strip, 6- First layer vacuum bag film, 7- Second layer vacuum bag film, 8- Upper guide net, 9- Separation film. Detailed Implementation

[0031] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0032] In addition, unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be obtained by purchasing them from the market or prepared by existing methods.

[0033] The basic process flow of a blade leading edge UD prefabrication is as follows: Figure 1 The process includes: preparation of the leading edge UD prefabrication mold 1, cleaning of the leading edge UD prefabrication mold, positioning and marking of auxiliary materials, laying of auxiliary materials under the UD fabric layer, positioning and marking of the UD fabric layer, laying of the UD fabric layer, laying of auxiliary materials on the UD fabric layer, resin pouring and curing, demolding, prefabrication of the leading edge UD, placement of the leading edge UD, casting and molding of the prefabricated leading edge UD and shell, and demolding of the blades. The specific process is as follows:

[0034] I. Leading Edge UD Prefabrication Mold Forming Process

[0035] The specific implementation process is as follows: Based on the leading edge UD design parameters of different projects, a leading edge UD prefabricated mold 1 is manufactured. The mold surface matches the main mold. After the mold is placed, it facilitates on-site operation, improves production efficiency and product quality. The application area can be selected according to the actual situation.

[0036] II. Leading Edge UD Prefabrication Process

[0037] The specific implementation process is as follows:

[0038] 1. Lay the UD fabric layer under auxiliary materials according to the process requirements, and draw the chordal and axial positioning lines of the fabric layer. The under auxiliary materials include the lower guide net 3 and the release cloth 4.

[0039] 2. Lay the UD fabric layer strictly according to the design and process requirements, trim the fabric layer, and confirm the dimensions simultaneously;

[0040] 3. Lay the upper auxiliary materials, including the isolation film 9, the upper guide net 8, and the vacuum bag film. Strictly position the auxiliary materials, seal the vacuum bag film, open the vacuum pump valve, and begin vacuuming. Simultaneously adjust the vacuum bag film to fit tightly against the flange corners, flow channels, and exhaust vacuum pipes, ensuring the vacuum bag film is not taut after vacuuming. At the same time, press the sealing strip 5 along the edge of the UD precast mold to ensure the vacuum bag film adheres tightly to the sealing strip 5 and the mold, preventing air leakage. After tightening one layer of vacuum bag film 6 (65μm thick, 1m / 1.5m wide, 60m / roll), when the vacuum pump reading is ≤-81Kpa, seal the second layer of vacuum bag film 7 (65μm thick, 1m / 1.5m wide, 60m / roll). Connect the two layers of bag film with the upper guide net 8 or breathable cotton. The upper guide net 8 or breathable cotton is laid in a "Z" shape, connecting the front and rear edges and extending from the root of the mold to the tip.

[0041] After sealing the two layers of film, insert the spiral steel wire tube into the glue injection seat. After the connection is completed, when the vacuum gauge reading inside the first layer of vacuum film 6 is less than 20 mbar, close the first layer of vacuum pump and the valve of the air extraction pipeline, keep all air extraction ports open, and continue to extract air from the second layer of vacuum film 7. Start pressure holding. The pressure holding rule is that the change should not exceed 15 mbar within 10 minutes, which means that the film is well sealed and vacuum filling can be carried out.

[0042] 4. At the start of pouring, set the mold temperature to 35-50℃. After pouring, adjust the temperature to 65-85℃ until curing takes 5-8 hours. After the product surface has cured, check the hardness of the flange and the main surface every 5m, randomly selecting sections along the chord direction. Simultaneously, measure the Tg value according to the "Fiberglass and Adhesives Tg Test Specification". A Tg > 70℃ and a Shore hardness > 55HD are acceptable. At the same time, remove the cotton blanket from the web and turn off the hot water circulation. Demolding is only allowed when the temperature of all areas of the product surface drops below 45℃.

[0043] 5. Adjust the crane lifting position according to the fiberglass cloth layer. First, lift the tip to detach it from the mold. After the base is lifted, load and move the lifting fixture. After product 2 is removed from the mold, place the conformal guard plate for lifting. The lifting point should be less than 1m from the point where the product is manually removed from the mold, the lifting height should be less than 0.5m, and the distance between adjacent lifting straps should be less than 4m. After the leading edge UD is completely removed from the mold, lift the entire leading edge UD onto the storage fixture for storage. After inspection and approval by the inspectors, it is ready for use in the layering process.

[0044] III. Prefabricated Leading Edge UD and Shell Injection Molding Process

[0045] The prefabricated leading edge UD is integrally cast with the shell. According to the project design and process plan, the prefabricated leading edge UD is placed in the leading edge area of ​​the shell mold, and is completely attached to the inner and outer fabric layers of the shell, eliminating fabric layer displacement and wrinkles in the leading edge UD area, and further improving product quality.

[0046] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0047] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A pre-forming process for the leading edge UD of a blade, characterized in that, Includes the following steps: S1: Prepare the leading edge UD preform; S2: Leading edge UD prefabrication: including laying the lower auxiliary material of UD fabric layer, laying the leading edge UD fabric layer, laying the upper auxiliary material of UD fabric layer, vacuum injection and demolding; S3: The prefabricated leading edge UD is integrally cast with the shell.

2. The blade leading edge UD prefabrication process as described in claim 1, characterized in that: The preparation of the leading edge UD prefabricated mold includes: making the leading edge UD prefabricated mold according to the leading edge UD design parameters of different projects, and matching the mold surface with the main mold.

3. The blade leading edge UD prefabrication process as described in claim 1, characterized in that: Laying the UD fabric layer under the auxiliary materials includes: laying the UD fabric layer under the auxiliary materials according to the process requirements, and drawing the chord and axial positioning lines of the fabric layer. The auxiliary materials include the lower guide net and the release cloth.

4. The blade leading edge UD prefabrication process as described in claim 1, characterized in that: Laying the leading edge UD fabric layer includes: laying the UD fabric layer according to the design and process requirements, trimming the fabric layer, and simultaneously confirming the dimensions.

5. The blade leading edge UD prefabrication process as described in claim 1, characterized in that: The process of laying the UD fabric layer auxiliary materials includes: laying the fabric layer auxiliary materials, including the release membrane, the upper guide net, and the vacuum bag film. The auxiliary materials are strictly positioned, the vacuum bag film is sealed, the vacuum pump valve is opened, and the vacuum is started. At the same time, the vacuum bag film is adjusted to fit tightly against the flange corners, flow channels, and exhaust vacuum pipes, so that the vacuum bag film is not taut after the vacuum is tightened. At the same time, the sealing strip is pressed along the edge of the mold to make the vacuum bag film fit tightly against the sealing strip and the mold, without air leakage.

6. The blade leading edge UD prefabrication process as described in claim 5, characterized in that: The auxiliary materials for laying the UD fabric layer also include: after the first layer of vacuum bag film is tightened, when the vacuum pump reading is ≤-81Kpa, sealing the second layer of vacuum bag film, and connecting the two layers of vacuum bag film with a flow guide net or breathable cotton. The flow guide net or breathable cotton is laid in a Z-shape connecting the front and rear edges and extending from the root of the mold to the tip of the mold.

7. The blade leading edge UD prefabrication process as described in claim 6, characterized in that: The auxiliary materials for laying the UD fabric layer also include: after sealing the two layers of vacuum bag film, inserting the spiral steel wire tube into the glue injection seat. After the connection is completed, when the vacuum gauge reading inside the first layer of vacuum bag film is less than 20 mbar, close the first layer of vacuum pump and the valve of the air extraction pipeline, keep all air extraction ports open, and continue to extract air from the second layer of vacuum bag film to start pressure holding. The pressure holding rule is that the change should not exceed 15 mbar within 10 minutes, which indicates that the vacuum bag film is in good sealing condition and vacuum injection can be carried out.

8. The blade leading edge UD preforming process as described in claim 1, characterized in that: Vacuum infusion includes: at the beginning of infusion, the mold is set to 35-50℃, and after infusion, it is adjusted to 65-85℃ until curing for 5-8 hours. After the product surface is cured, the hardness of the flange and the main surface is tested every 5m. The chord position of the cross section is randomly selected, and the Tg value is measured at the same time. Tg > 70℃ and Shore hardness > 55HD are qualified. At the same time, the cotton quilt of the web plate is lifted, the hot water circulation is turned off, and the temperature of all areas of the product surface drops below 45℃ before demolding.

9. The blade leading edge UD prefabrication process as described in claim 1, characterized in that: The prefabricated leading edge UD and the shell are integrally cast together by: placing the prefabricated leading edge UD on the leading edge area of ​​the shell mold, so that it is completely attached to the inner and outer fabric layers of the shell, and eliminating the displacement and wrinkles of the fabric layers in the leading edge UD area.

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