A wind turbine generator segmented tower end stress concentration elimination structure

Abstract

The application discloses a stress concentration eliminating structure at the end of a segmented tower of a wind turbine, which is arranged on a segmented tower barrel connected in a segmented manner, and a thickened part is arranged on the adjacent side wall of adjacent tower barrel segments, and a longitudinal flange connecting plate is arranged on the tower barrel segment, and the thickened part corresponds to the end of the longitudinal flange connecting plate. The application has the advantages that the thickness of the plate at the welding end of the longitudinal flange connecting plate and the tower body is increased to weaken the stress concentration at the position, and if the thickness of the whole plate is increased, the weight is greatly increased; the application realizes the local thickening of the end of the tower barrel segment through the thickened part, weakens the stress concentration, avoids the excessive weight increase of the tower barrel segment, and improves the reliability of the tower.

Description

Technical Field

[0001] This invention relates to the field of tower segmentation technology, and in particular to a stress concentration relief structure at the end of a segmented wind turbine tower. Background Technology

[0002] A robust and reliable wind turbine tower is the primary condition for ensuring the safe operation of wind turbines. With the rapid development of the wind power industry, the application of high wind speeds, heavy loads, and long blades is becoming increasingly common. As the supporting structure of the wind turbine, the tower diameter and height are also increasing to meet the safe operation requirements. However, the maximum height limit for road transport in my country is currently 5 meters. Due to these road transport restrictions, the development of new turbine models is greatly affected. Segmented towers have become a new trend, as segmented transport can effectively solve the road restriction problem. However, the assembly and reliability of segmented towers have become a social challenge.

[0003] Traditional segmented tower connections, such as Figure 1 As shown, tower section I 101 and tower section II 102 are mainly connected by two longitudinal flange connecting plates 103 using high-strength bolts, nuts, and gaskets; flange sections I 104 and II 105 are mainly connected by flange connecting plate 106. Furthermore, as in Chinese patent CN2017215234379, authorized and announced on August 7, 2018, a tower section connection structure includes several tower sections. Longitudinal flanges are welded at the division points of the tower sections, and the longitudinal flanges on two tower sections are fixedly connected by connectors and bolts to form an integral tower section. The convenience of connection is improved by adding connectors. However, the connector structure significantly increases the overall weight of the tower, which is not conducive to achieving tower weight reduction. The shortcomings of the existing segmented tower technology are that longitudinal flange connecting plates are welded on both sides of tower segment I and tower segment II in a tower section. However, due to the extrusion deformation of high-strength bolts during splicing, the long-term high load of the wind turbine during operation, and the influence of vortex-induced vibration, stress concentration occurs at the weld between the longitudinal flange and the tower, especially at the end position, which easily leads to welding fatigue, resulting in tearing and thus causing safety problems. Summary of the Invention

[0004] To address the problem in existing technologies where excessive stress at the end of the longitudinal flange connecting plate affects the reliability of tower segment connections during bolted connections, this application provides a stress concentration elimination structure at the end of a segmented wind turbine tower. This structure reduces the connection stress between the end of the longitudinal flange connecting plate and the tower, thereby improving the reliability of the tower.

[0005] To achieve the above objectives, the present invention adopts the following technical solution.

[0006] A stress concentration relief structure for the end of a segmented tower of a wind turbine is provided. The segmented tower segments are used for segmented connection. The adjacent side walls of adjacent tower segments are provided with thickened portions. The tower segments are provided with longitudinal flange connecting plates. The thickened portions are located at the ends of the longitudinal flange connecting plates.

[0007] By increasing the thickness of the plate at the welded end of the longitudinal flange connection plate and the tower body, the stress concentration at this location can be reduced. However, if the thickness of the entire plate is increased, the weight will increase significantly. This application achieves local thickening of the tower section ends by thickening the section, thereby reducing stress concentration and avoiding excessive weight increase of the tower sections, thus improving the reliability of the tower.

[0008] Preferably, the thickened portion corresponds to the upper end of the longitudinal flange connecting plate, and the upper end of the longitudinal flange connecting plate is provided with a transition arc surface, the upper end of which is tangent to the wall surface of the tower segment. The provision of the transition arc surface makes the end of the longitudinal flange connecting plate smoothly transition to the tower segment, reducing the problem of stress concentration at the end of the longitudinal flange connecting plate.

[0009] Preferably, the cross-sectional shape of the transition arc surface is circular, and the radius of the transition arc surface is between 2 and 3 times the height of the longitudinal flange connection plate. A larger radius for the transition arc surface creates a large rounded corner structure, and the corresponding longitudinal flange connection plate has a longer length, effectively avoiding stress concentration.

[0010] Preferably, the thickened section is fixed to the tower section by full-penetration welding. Full-penetration welding ensures high reliability of the weld formation.

[0011] Preferably, the inner side of the thickened section is coplanar with the inner side of the tower section, and the thickness of the thickened section is 1.1 to 1.8 times the thickness of the tower section. The thickened section provides reinforcement relative to the tower section, and the thickened section is welded to the longitudinal flange connecting plate using a full penetration welding method. Controlling the thickness of the thickened section to be 1.1 to 1.8 times the thickness of the tower section ensures the reinforcing effect of the thickened section, and because the thicknesses of the thickened section and the tower section are similar when welded together, the welding reliability is good.

[0012] Preferably, the thickened section includes a fixed section connected to the upper end of the longitudinal flange connecting plate. The fixed section has an integrally formed stress-reducing section above the longitudinal flange connecting plate, and the projection of the transition arc surface in the radial direction of the tower is located on the fixed section. The fixed section is connected to the longitudinal flange connecting plate, and the stress-reducing section, together with other fixed section areas outside the longitudinal flange connecting plate, forms a stress buffer zone surrounding the upper end of the longitudinal flange connecting plate, thereby significantly reducing the stress on the longitudinal flange connecting plate.

[0013] Preferably, the lower end of the fixed section is arc-shaped. This facilitates the welding of the thickened section and the tower sections, avoids welding dead angles, and improves welding reliability.

[0014] Preferably, the longitudinal flange connecting plate has several connecting holes arranged in a linear array, with the thickened portion corresponding to at least three connecting holes on the longitudinal flange connecting plate. The thickened portion corresponding to at least three connecting holes reliably reinforces the position of the connecting block at the upper end of the longitudinal flange connecting plate.

[0015] Preferably, a transition fillet is provided between the edge of the thickened section and the tower section. This improves the reliability of the connection between the thickened section and the tower section, enhances the quality of the outer surface of the tower, and prevents stress damage.

[0016] The beneficial effects of this invention are: it can reduce the connection stress between the end of the longitudinal flange connecting plate and the tower, thereby improving the reliability of the tower; the radius of the transition arc surface is set relatively large compared to the height of the longitudinal flange connecting plate, forming a large rounded corner structure, and the length of the longitudinal flange connecting plate corresponding to the transition arc surface is relatively long, effectively avoiding the problem of stress concentration. Attached Figure Description

[0017] Figure 1 It is the connection structure of the segmented flange in the existing technology.

[0018] Figure 2 This is a schematic diagram of the structure of the present invention.

[0019] Figure 3 yes Figure 2 The illustrated embodiment is shown from another angle.

[0020] Figure 4 This is an internal sectional view of the present invention.

[0021] Figure 5 yes Figure 4 Enlarged diagram of point A in the middle.

[0022] Figure 6 This is an enlarged schematic diagram of the welding position between the thickened part and the tower section in this invention.

[0023] In the diagram: Tower section I 101, Tower section II 102, Longitudinal flange connecting plate 103, Flange section I 104, Flange section II 105, Flange connecting plate 106, Tower section 1, Thickened section 2, Longitudinal flange connecting plate 3, Connecting hole 4, Transition arc surface 5, Fixed section 6, Stress section 7, Transition fillet 8, Flange section 9. Detailed Implementation

[0024] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0025] Example 1,

[0026] like Figures 2 to 6As shown, a stress concentration relief structure for the end of a segmented tower of a wind turbine is provided. On the segmented tower segments 1, thickened portions 2 are provided on adjacent sidewalls of adjacent tower segments 1. The inner side of the thickened portions 2 is coplanar with the inner side of the tower segment 1, and the thickness of the thickened portions 2 is 1.1 to 1.8 times the thickness of the tower segment 1. The cross-sectional shape of the thickened portions 2 is an arc concentric with the tower segment 1. The thickened portions 2 are fully penetrated and welded to the tower segment 1. A longitudinal flange connecting plate 3 is provided on the tower segment 1, and the thickened portions 2 correspond to the upper end of the longitudinal flange connecting plate 3. The longitudinal flange connecting plate 3 has several connecting holes 4 arranged in a linear array, and the thickened portions 2 correspond to at least three connecting holes 4 on the longitudinal flange connecting plate 3. A transition arc surface 5 is provided at the upper end of the longitudinal flange connecting plate 3, and the upper end of the transition arc surface 5 is tangent to the wall surface of the tower segment 1 on which it is located. The transition arc surface 5 has a circular arc cross-section, and its radius is between 2 and 3 times the height of the longitudinal flange connecting plate 3. The thickened part 2 includes a fixed section 6 connected to the upper end of the longitudinal flange connecting plate 3, and the lower end of the fixed section 6 is circular arc-shaped. The fixed section 6 has an integral stress section 7 above the longitudinal flange connecting plate 3, and the projection of the transition arc surface 5 in the radial direction of the tower is located on the fixed section 6. A transition fillet 8 is provided between the edge of the thickened part 2 and the tower section 1.

[0027] In the manufacturing process of this application, a certain size of plate is first cut off from the end position of the original tower segment 1 corresponding to the welding position between the longitudinal flange connecting plate 3 and the tower segment 1; then, a plate of the same shape and material but with a larger thickness is welded on, which is the thickened part 2. The thickened part 2 ensures that the inner side of the tower is flush with the outer side; then, the end of the longitudinal flange connecting plate 3 is rounded and tangent to the inner wall of the tower; finally, the longitudinal flange connecting plate 3 and the end of the tower body are fully penetrated welded.

[0028] In use, this application employs the same connection method as traditional tower section 1, connecting adjacent longitudinal flange connecting plates 3 on adjacent tower sections 1 using high-strength bolts and nuts. The high-strength bolts correspond one-to-one with the connecting holes 4 on the longitudinal flange connecting plates 3. Flange sections 9 are respectively provided at the upper end of the tower section 1, and the flange sections 9 are bolted together via flange connecting plates.

[0029] This application reduces stress concentration at the welded end of the longitudinal flange connecting plate 3 and the tower section 1 by thickening the part 2; increases the welding reliability at the welded end of the longitudinal flange connecting plate 3 and the tower section 1; reduces the overall weight of the tower; reduces transportation difficulty; and makes it feasible to build a large-diameter tower.

Claims

1. A stress concentration relief structure at the end of a segmented tower for a wind turbine, characterized in that, For tower sections used in segmented connections, thickened portions are provided on adjacent sidewalls of adjacent tower sections. The thickened portions are flush with the inner side of the tower and protrude on the outer side. The tower sections are provided with longitudinal flange connecting plates, and the thickened portions are located at the ends of the longitudinal flange connecting plates. The thickened portion includes a fixed section connected to the upper end of the longitudinal flange connecting plate. The fixed section is integrally provided with a stress section above the longitudinal flange connecting plate. The stress section, together with other fixed section areas outside the longitudinal flange connecting plate, forms a stress buffer zone surrounding the upper end of the longitudinal flange connecting plate.

2. The stress concentration relief structure at the end of a segmented tower of a wind turbine according to claim 1, characterized in that, The upper end of the longitudinal flange connecting plate is provided with a transition arc surface, and the upper end of the transition arc surface is tangent to the wall surface of the tower section.

3. The stress concentration relief structure at the end of a segmented tower of a wind turbine according to claim 2, characterized in that, The cross-sectional shape of the transition arc surface is circular arc, and the radius of the transition arc surface is between 2 and 3 times the height of the longitudinal flange connection plate.

4. The stress concentration relief structure at the end of a segmented tower of a wind turbine according to claim 1, characterized in that, The thickened section is fixed to the tower section by full-penetration welding.

5. A stress concentration relief structure for the end of a segmented tower of a wind turbine according to claim 1, characterized in that, The inner side of the thickened portion is coplanar with the inner side of the tower section, and the thickness of the thickened portion is 1.1 to 1.8 times the thickness of the tower section.

6. A stress concentration relief structure for the end of a segmented tower of a wind turbine according to claim 2 or 3, characterized in that, The projection of the transition arc surface in the radial direction of the tower is located on the fixed section.

7. A stress concentration relief structure for the end of a segmented tower of a wind turbine according to claim 6, characterized in that, The lower end of the fixed section is arc-shaped.

8. A stress concentration relief structure for the end of a segmented tower of a wind turbine according to claim 1 or 4, characterized in that, The longitudinal flange connecting plate is provided with a number of connecting holes arranged in a linear array, and the thickened part corresponds to at least three connecting holes on the longitudinal flange connecting plate.

9. A stress concentration relief structure for the end of a segmented tower of a wind turbine according to claim 1 or 5, characterized in that, The thickened section has a transition rounded corner between its edge and the tower section.

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