Pultruded panels, pultruded spars and wind turbine blades

Abstract

The present disclosure relates to a kind of pultrusion plate, pultrusion girder and wind power blade, the pultrusion girder includes several layers of pultrusion unit, several layers of the pultrusion unit is arranged in stack along first direction, each layer of the pultrusion unit includes several pultrusion plates, and several pultrusion plates of each layer of the pultrusion unit is arranged along second direction, the first direction and the second direction intersect, wherein, at least one side of the pultrusion plate in the second direction is provided with several transition grooves, and several transition grooves in the same side are spaced apart along third direction;The transition groove extends to at least one side of the pultrusion plate in the first direction, and the third direction is perpendicular to the first direction and the second direction.The technical scheme provided by the present disclosure can reduce the possibility of interlaminar defect of pultrusion girder, improve the overall performance of wind power blade.

Description

Technical Field

[0001] This disclosure relates to the technical field of wind power equipment, and particularly to a pultruded plate, a pultruded main beam, and a wind turbine blade. Background Technology

[0002] Pultruded main beams are usually assembled and bonded from multiple pultruded plates. When stacking pultruded plates, due to dimensional errors and / or stacking errors, adjacent pultruded plates may overlap or misalign.

[0003] This offset causes overlapping and misalignment between two adjacent transverse interfaces and / or two adjacent vertical interfaces of the pultruded main beam, resulting in blockage of the splice joint, reduced grouting efficiency, and poor interlayer grouting and wetting, thus affecting the overall performance of the blade. Utility Model Content

[0004] The purpose of this disclosure is to provide a pultruded plate, a pultruded main beam, and a wind turbine blade, which can reduce the possibility of interlayer defects in the pultruded main beam and improve the overall performance of the wind turbine blade.

[0005] According to one aspect of this disclosure, a pultruded main beam is provided, the pultruded main beam comprising a plurality of pultruded units stacked along a first direction, each pultruded unit comprising a plurality of pultruded plates, and the plurality of pultruded plates of each pultruded unit being arranged along a second direction, the first direction and the second direction intersecting, wherein at least one side of the pultruded plate in the second direction is provided with a plurality of transition grooves, and the plurality of transition grooves on the same side are spaced apart along a third direction; the transition grooves extend to at least one side of the pultruded plate in the first direction, the third direction being perpendicular to the first direction and the second direction.

[0006] The technical solution provided in this disclosure, by providing a transition groove on at least one side of the pultruded plate along the second direction and extending the transition groove to at least one side of the pultruded plate along the first direction, can increase the interface space between two adjacent pultruded plates in the first direction and the interface space between two connected pultruded plates in the second direction, thereby widening the flow channel of the adhesive, accelerating the injection speed, and improving production efficiency. Simultaneously, the transition groove acts as a tolerance area for adjacent interface spaces. That is, when the pultruded plates are misaligned to a certain extent during stacking, the adjacent interface spaces can still be connected through the transition groove, allowing the adhesive to flow smoothly and preventing the flow gaps from closing due to mutual stacking, thus reducing the possibility of interlayer defects in the pultruded main beam and improving the overall performance of the wind turbine blade.

[0007] Optionally, the inner wall surface of the transition groove is a smooth curved surface.

[0008] By constructing the inner wall of the transition groove as a smooth curved surface, the stress can be evenly distributed along the surface, avoiding stress concentration and reducing the impact of the transition groove on the mechanical properties of the pultruded plate, thereby ensuring the mechanical properties of the wind turbine blade. Simultaneously, when the adhesive flows within the transition groove, the smooth curved surface also reduces the flow resistance of the adhesive, improves injection efficiency, and inhibits bubble formation and retention, ensuring injection quality.

[0009] Optionally, the inner wall of the transition groove is an arc-shaped surface, and the groove depth decreases from both ends of the transition groove in the third direction towards the middle.

[0010] The above method allows the transition groove to be formed by rotating and grinding a circular or elliptical grinding wheel, simplifying the grinding wheel structure and production process, and reducing production costs.

[0011] Optionally, the interval length between two adjacent transition grooves on one side of the pultruded plate in the second direction ranges from 0.3m to 5m; the number of layers in the pultrusion unit ranges from 3 to 20.

[0012] By limiting the interval length between two adjacent transition grooves, the adhesive can be fully spread through the transition grooves, ensuring the injection efficiency and quality of the pultrusion unit with 3-20 layers of pultruded plates. This also reduces the impact of overly dense transition grooves on the mechanical properties of the pultruded plates, thus ensuring the product quality of wind turbine blades.

[0013] Optionally, the length of the transition groove along the third direction ranges from 0.5cm to 2cm.

[0014] The above solution reduces the impact on the mechanical properties of the pultruded plate by limiting the size of the transition groove.

[0015] Optionally, the transition groove extends to the side of the pultruded plate located in the first direction.

[0016] The above solution not only improves production efficiency and ensures that adjacent interface spaces can still be connected through transition grooves when pultruded plates are misaligned to a certain extent during stacking, but also reduces the volume of transition grooves and decreases the impact on the mechanical properties of pultruded plates.

[0017] Optionally, the transition groove is located on the side of the pultruded plate in the second direction.

[0018] The above solution reduces the number of transition grooves required, thus minimizing the impact on the mechanical properties of the pultruded plate.

[0019] Optionally, the transition groove extends to the two opposite sides of the pultruded plate in the first direction.

[0020] The above scheme further increases the interface space between the two pultruded plates connected in the second direction, ensuring stable connection between the two adjacent interface spaces in the vertical direction and guaranteeing the injection quality.

[0021] Optionally, an interlayer fabric may be laid between two adjacent pultrusion units.

[0022] By employing the above-described method, the interlayer fabric is laid between two adjacent pultrusion units, thereby increasing the flow rate of the adhesive and improving the injection efficiency. Simultaneously, it results in a tighter interface bond after injection, which is beneficial for improving the mechanical performance transfer efficiency of the entire wind turbine blade structure and enabling better collaboration among the various materials.

[0023] Optionally, the transition groove is formed by grinding.

[0024] The above solution utilizes a grinding process to reduce stress concentration in the pultruded plate during the processing of the transition groove, thereby reducing the possibility of damage to the pultruded plate during the processing of the transition groove.

[0025] Optionally, from a cross-sectional view of the pultruded plate, the opposite ends of the pultruded plate in the second direction narrow outward along the second direction.

[0026] With the above scheme, after multiple pultruded plates are stacked and assembled, a large reserved space can be formed between the trapezoidal sides of two adjacent pultruded plates, thereby further improving the injection efficiency and allowing a certain degree of misalignment and connection of the pultruded plates during the stacking process, without the need for precise alignment and stacking, thus reducing the difficulty of the stacking process.

[0027] According to another aspect of this disclosure, a wind turbine blade includes the aforementioned pultruded main beam.

[0028] By incorporating the aforementioned pultruded main beam into the wind turbine blades, the bending, torsion, and fatigue resistance of the wind turbine blades can be enhanced, ensuring the stable operation of the wind turbine units.

[0029] According to another aspect of this disclosure, a pultruded plate has a plurality of transition grooves on at least one side of the pultruded plate in a second direction, and the plurality of transition grooves on the same side are spaced apart along a third direction; the transition grooves extend to at least one side of the pultruded plate in a first direction, the first direction and the second direction intersect, and the third direction is perpendicular to the first direction and the second direction; the inner wall surface of the transition groove is a smooth curved surface. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A schematic cross-sectional view of a pultruded main beam according to an embodiment of the present disclosure is shown;

[0032] Figure 2 A top view schematic diagram of a pultruded main beam according to an embodiment of the present disclosure is shown;

[0033] Figure 3 A schematic cross-sectional view of a pultruded plate according to an embodiment of the present disclosure is shown;

[0034] Figure 4 A partial perspective view of a pultruded plate according to an embodiment of the present disclosure is shown;

[0035] Figure 5 A schematic cross-sectional view of a pultruded plate according to another embodiment of the present disclosure is shown;

[0036] Figure 6 A schematic cross-sectional view of a pultruded plate according to yet another embodiment of the present disclosure is shown;

[0037] Figure 7 A schematic diagram showing the flow of adhesive during the grouting process of a pultruded main beam according to an embodiment of the present disclosure is shown.

[0038] Figure 8 A schematic cross-sectional view of a pultruded plate according to another embodiment of the present disclosure is shown.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1000, Pultruded main beam;

[0041] 100. Pultrusion unit; 110. Pultrusion plate; 111. Transition groove;

[0042] 200. Interlayer fabric. Detailed Implementation

[0043] Pultruded main beams are typically assembled and bonded from multiple pultruded plates. During the stacking of pultruded plates, due to dimensional and / or stacking errors, adjacent pultruded plates may overlap or misalign vertically or horizontally. This overlap and misalignment causes misalignment between adjacent transverse and / or vertical interfaces of the pultruded main beam, resulting in joint blockage, reduced grouting efficiency, and poor interlayer wetting, ultimately affecting the overall performance of the blade.

[0044] To address this, the present disclosure employs an interlayer fabric laid between the upper and lower pultruded plates, thereby allowing the resin adhesive to effectively penetrate between the two pultruded plates and complete the bonding process. Furthermore, a groove is provided at at least one included angle of each pultruded plate, forming a tolerance area to allow stable communication even with a certain offset between adjacent lateral and / or vertical interface spaces. This ensures smooth resin adhesive flow and prevents the flow gaps from closing due to stacking, thus hindering resin adhesive flow.

[0045] Meanwhile, the two adjacent grooves along the vertical direction also form a vertical flow channel, which allows the resin to flow stably not only in the horizontal direction but also in the vertical direction, thereby improving the injection efficiency, enabling the resin to penetrate effectively, ensuring the injection quality, avoiding delamination defects, and improving the injection efficiency.

[0046] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this disclosure, but not all embodiments.

[0047] like Figures 1 to 6 As shown, this disclosure presents a pultruded main beam 1000, which serves as the main load-bearing structure for wind turbine blades, providing the blades with bending and torsional resistance. Specifically, the pultruded main beam 1000 includes several layers of pultruded units 100, which are stacked along a first direction. Each pultruded unit 100 includes several pultruded plates 110, and the pultruded plates 110 of each pultruded unit 100 are arranged along a second direction, which intersects with the first direction. Exemplarily, the several layers of pultruded units 100 can be vertically aligned or staggered. When the several layers of pultruded units 100 are vertically aligned, the several pultruded plates 110 can be considered as several layers and several columns arranged. The material of the pultruded plates 110 may include glass fiber, carbon fiber, and carbon-glass composites, etc.

[0048] Viewed in cross-section, the pultruded plate 110 is approximately rectangular, with two sides in the second direction and the top and bottom sides in the first direction. At least one side of the pultruded plate 110 in the second direction has a transition groove 111, and these transition grooves 111 on the same side are spaced apart along a third direction. The transition grooves 111 extend to at least one side of the pultruded plate 110 in the first direction, with the third direction perpendicular to both the first and second directions. This arrangement of the transition grooves 111 increases the interface space between two adjacent pultruded plates 110 in the first direction and between two connected pultruded plates 110 in the second direction, thereby widening the flow path of the adhesive (e.g., resin), accelerating the filling speed, and improving production efficiency. Meanwhile, the transition groove 111 acts as a tolerance zone between two adjacent interface spaces. This means that even if the pultruded plates 110 are misaligned to a certain extent during stacking, the two adjacent interface spaces can still be connected through the transition groove 111. This allows the adhesive to flow smoothly, preventing the flow gaps from closing due to stacking and affecting the adhesive flow. This reduces the likelihood of interlayer defects in the pultruded main beam 1000 and improves the overall performance of the wind turbine blade. It should be noted that the first direction can be the thickness direction of the pultruded plate 110, the second direction is the width direction of the pultruded plate 110, and the third direction is the length direction of the pultruded plate 110.

[0049] For example, such as Figure 7 As shown, when injecting adhesive into the pultruded main beam 1000, the adhesive can be injected from the upper left of the pultruded main beam 1000, and a flow guiding medium can be laid at the bottom of the pultruded main beam 1000. During the entire injection process, the adhesive permeates from left to right. Simultaneously, the adhesive at the bottom, guided by the flow guiding medium, flows faster than the adhesives between other layers, and the adhesive at the bottom forms an upward flow at each vertical interface space, thus achieving multi-channel flow and permeation of the adhesive from left to right and from bottom to top. Alternatively, flow guiding medium can be laid at both the top and bottom of the pultruded main beam 1000, allowing the adhesive to flow and permeate in multiple channels from left to right, from top to bottom, and from bottom to top.

[0050] In some embodiments, the inner wall surface of the transition groove 111 can be a non-smooth curved surface, or in other words, the inner wall surface of the transition groove 111 has an included angle. For example, the transition groove 111 can be a rectangular groove, a trapezoidal groove, or a triangular groove, etc.

[0051] In this embodiment, after the transition groove 111 is formed, a reinforcing layer can be set on the inner wall surface of the transition groove 111 by means of coating, hot melting or other methods to make up for the defect of reduced mechanical performance caused by the setting of the transition groove 111 and maintain the mechanical performance of the wind turbine blade.

[0052] In some other embodiments, such as Figure 3 and Figure 4 As shown, the inner wall of the transition groove 111 is a smooth curved surface, or in other words, the inner wall of the transition groove 111 has no included angle regions. This allows the stress to be evenly distributed along the curved surface, avoiding stress concentration and reducing the impact of the transition groove 111 on the mechanical properties of the pultruded plate 110, thereby ensuring the mechanical properties of the wind turbine blade.

[0053] Meanwhile, as the adhesive flows in the transition groove 111, the smooth curved surface can reduce the flow resistance of the adhesive, improve the injection efficiency, and also suppress the generation and retention of air bubbles, thus ensuring the injection quality.

[0054] For example, the inner wall of the transition groove 111 is an arc-shaped surface, and the groove depth of the transition groove 111 decreases from both ends in a third direction towards the middle. This allows it to be formed by rotary grinding using a circular or elliptical grinding wheel, simplifying the grinding wheel structure and manufacturing operations, and reducing production costs. As another example, the inner wall of the transition groove 111 can also be an irregular spline curve forming a curved surface.

[0055] In some embodiments, the interval length between two adjacent transition grooves 111 on one side of the pultruded plate 110 in the second direction ranges from 0.3m to 5m. Furthermore, the number of layers in the pultrusion unit 100 ranges from 3 to 20, or in other words, the pultruded plate 110 in the pultrusion unit 100 has n layers, where n ranges from 3 to 20. Thus, by setting the interval length range between two adjacent transition grooves 111, the adhesive can be fully spread through the transition grooves 111, ensuring the injection efficiency and injection quality of the pultrusion unit 100 with 3-20 layers of pultruded plates 110, while also reducing the impact of excessively dense transition grooves 111 on the mechanical properties of the pultruded plate 110, thereby ensuring the product quality of the wind turbine blade.

[0056] Furthermore, the length of the transition groove 111 along the third direction ranges from 0.5cm to 2cm, thereby reducing the impact on the mechanical properties of the pultruded plate 110 by limiting the size of the transition groove 111.

[0057] The transition groove 111 may extend only to the side of the pultruded plate 110 located in the first direction, for example, as shown in the example. Figure 3As shown, the transition groove 111 can extend only to the top surface of the pultruded plate 110. Alternatively, the transition groove 111 can extend only to the bottom surface of the pultruded plate 110, thus forming a transition groove 111 located in the included angle region on one side of the pultruded plate 110. In this way, while achieving the aforementioned improvements in production efficiency and ensuring that adjacent interface spaces can still be connected through the transition groove 111 even when the pultruded plates 110 experience some degree of misalignment during stacking, the volume of the transition groove 111 can also be reduced, minimizing its impact on the mechanical properties of the pultruded plate 110.

[0058] like Figure 6 As shown, the transition groove 111 can also extend to the two opposite sides of the pultruded plate 110 in the first direction, or in other words, the transition groove 111 penetrates the upper and lower sides of the pultruded plate 110, thereby further increasing the interface space between the two connected pultruded plates 110 in the second direction, ensuring stable connection between the two vertically adjacent interface spaces, and ensuring the injection quality.

[0059] In some embodiments, such as Figure 3 As shown, the transition groove 111 can be provided only on one side of the pultruded plate 110 in the second direction, such as the left or right side of the pultruded plate 110, thereby reducing the number of transition grooves 111 and reducing the impact on the mechanical properties of the pultruded plate 110.

[0060] In some other implementations, such as Figure 5 As shown, the pultruded plate 110 may have transition grooves 111 on both opposite sides in the second direction. For example, the left and right sides of the pultruded plate 110 may have transition grooves 111, thereby further widening the cross-sectional area of ​​the adhesive flow channel and increasing the range in which the pultruded plates 110 can be stacked and misaligned.

[0061] In some embodiments, see again Figure 1 As shown, the pultruded main beam 1000 may also include an interlayer fabric 200, which is laid between two adjacent pultrusion units 100. This interlayer fabric 200 can increase the flow rate of the adhesive and improve the injection efficiency. The interlayer fabric 200 can be made of fiberglass cloth, which, due to its rough surface, provides a larger contact area with the pultruded plate 110 and the subsequently injected adhesive, resulting in a tighter interfacial bond. This improves the mechanical performance transfer efficiency of the entire wind turbine blade structure, allowing the various materials to work together more effectively.

[0062] For example, the interlayer fabric 200 between two adjacent pultruded plates 110 in the first direction may have one or more layers.

[0063] In some embodiments, such as Figure 8As shown, in the cross-sectional view of the pultruded plate 110, the two ends of the pultruded plate 110 located in the second direction narrow outward along the second direction, thereby forming a trapezoidal cross-sectional shape at the left and right ends of the pultruded plate 110. Thus, after multiple pultruded plates 110 are stacked and assembled, a larger reserved space can be formed between the trapezoidal sides of adjacent pultruded plates 110, thereby further improving the injection efficiency and allowing a certain degree of misalignment and connection of the pultruded plates 110 during the stacking process, eliminating the need for precise alignment and reducing the difficulty of the stacking process.

[0064] According to another aspect of this disclosure, a wind turbine blade is also provided, which includes the aforementioned pultruded main beam 1000.

[0065] In the process of combining the pultruded main beam 1000 with the wind turbine blade shell, the pultruded main beam 1000 can adopt a non-prefabricated structure. Specifically, several pultruded plates 110 and several interlayer fabrics 200 are first assembled into a whole, and then the whole is placed into the shell layup and cast and cured together with the blade shell. Of course, the pultruded main beam 1000 can also adopt a prefabricated structure. Several pultruded plates 110 and several interlayer fabrics 200 are first assembled into a whole, and then the whole is placed into a prefabricated mold and cast and cured to form a prefabricated part. Finally, the prefabricated part is demolded, trimmed, and placed into the shell layup and cast and cured together with the blade shell.

[0066] It should be noted that the specific structure of the pultruded main beam 1000 can be found in the detailed description in the above embodiments, and will not be repeated here.

[0067] According to another aspect of this disclosure, a pultruded plate 110 is also provided, wherein at least one side of the pultruded plate 110 in a second direction has a plurality of transition grooves 111, and the plurality of transition grooves 111 on the same side are spaced apart along a third direction. The transition grooves 111 extend to at least one side of the pultruded plate 110 in a first direction, wherein the first direction and the second direction intersect, and the third direction is perpendicular to the first direction and the second direction.

[0068] Furthermore, the inner wall surface of the transition groove 111 is a smooth curved surface.

[0069] It should be noted that the specific structure of the pultruded plate 110 and the transition groove 111 can be found in the detailed description in the above embodiments, and will not be repeated here.

[0070] The terms "upper" and "lower" used in this disclosure are used to describe the relative positional relationship of the various structures in the accompanying drawings. They are only for the purpose of clarity of description and are not intended to limit the scope of implementation of this disclosure. Changes or adjustments to the relative relationships without substantially altering the technical content should also be considered as part of the scope of implementation of this disclosure.

[0071] It should be noted that, in this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0072] Furthermore, in this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0073] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure.

Claims

1. A pultruded main beam, characterized in that, The pultruded main beam (1000) includes several layers of pultruded units (100), which are stacked along a first direction. Each layer of pultruded unit (100) includes several pultruded plates (110), and the several pultruded plates (110) of each layer of pultruded unit (100) are arranged along a second direction. The first direction and the second direction intersect. The pultruded plate (110) has a plurality of transition grooves (111) on at least one side in the second direction, and the plurality of transition grooves (111) on the same side are spaced apart along a third direction; the transition grooves (111) extend to at least one side of the pultruded plate (110) in the first direction, and the third direction is perpendicular to the first direction and the second direction.

2. The pultruded main beam according to claim 1, characterized in that, The inner wall of the transition groove (111) is a smooth curved surface.

3. The pultruded main beam according to claim 2, characterized in that, The inner wall of the transition groove (111) is an arc-shaped surface, and the groove depth of the transition groove (111) decreases from both ends of the transition groove (111) along the third direction towards the middle.

4. The pultruded main beam according to claim 1, characterized in that, The interval length between two adjacent transition grooves (111) on one side of the pultruded plate (110) in the second direction is in the range of 0.3m-5m; The number of layers in the pultrusion unit (100) ranges from 3 to 20.

5. The pultruded main beam according to claim 1, characterized in that, The length of the transition groove (111) along the third direction ranges from 0.5cm to 2cm.

6. The pultruded main beam according to any one of claims 1 to 5, characterized in that, The transition groove (111) extends to the side of the pultruded plate (110) located in the first direction.

7. The pultruded main beam according to claim 6, characterized in that, The transition groove (111) is provided on the side of the pultruded plate (110) located in the second direction.

8. The pultruded main beam according to any one of claims 1 to 5, characterized in that, The transition groove (111) extends to the two opposite sides of the pultruded plate (110) in the first direction.

9. The pultruded main beam according to claim 1, characterized in that, An interlayer fabric (200) is laid between two adjacent pultrusion units (100).

10. The pultruded main beam according to claim 2, characterized in that, The transition groove (111) is formed by grinding.

11. The pultruded main beam according to claim 1, characterized in that, From a cross-sectional view of the pultruded plate (110), the two opposite ends of the pultruded plate (110) in the second direction narrow outward along the second direction.

12. A wind turbine blade, characterized in that, The wind turbine blade includes the pultruded main beam (1000) as described in any one of claims 1 to 11.

13. A pultruded sheet, characterized in that, The pultruded plate (110) has a plurality of transition grooves (111) on at least one side in the second direction, and the plurality of transition grooves (111) on the same side are spaced apart along the third direction; the transition grooves (111) extend to at least one side of the pultruded plate (110) in the first direction, the first direction and the second direction intersect, and the third direction is perpendicular to the first direction and the second direction; The inner wall of the transition groove (111) is a smooth curved surface.

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