Annular Flange Contact Geometry for Vibration-Resistant Tower Joints
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Solution Overview
Problem
Existing flanged connections in large wind turbine tower installations face challenges with structural strength, fatigue resistance, and fastener loosening due to dynamic loads from wind and water waves, particularly in offshore environments.
Innovation Solution
A set of flanges with a specific design featuring annular toe and heel surface sections and an intermediate gap, allowing for even contact pressure distribution and high resistance to vibrations, while using fasteners with preloading to minimize prying and slacking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional flanged connections are used in large wind turbine tower installations, then the connection can be established quickly, but the structural strength and fatigue resistance are insufficient under high dynamic loads
Solution Approach 1:
The flange design incorporates different surface geometries in specific regions: a radially outwardly extending toe surface section and a radially inwardly extending heel surface section. These localized geometric variations create different contact characteristics in different areas of the flange, optimizing both strength distribution and installation characteristics without requiring complete redesign of the entire flange structure
Solution Approach 2:
The flange surfaces utilize curved geometries rather than flat surfaces. The toe surface and heel surface create arc-shaped contact regions that distribute loads more effectively across the flange interface. This curvature allows for better stress distribution and increased contact area, enhancing structural strength while maintaining installability
2Ease of manufacture
If conventional flanged connections are used, then the connection can be made with standard fasteners, but the fatigue resistance is insufficient due to dynamic response to wind and water wave loads
Solution Approach 1:
The flange design creates specific localized contact zones through the toe and heel surface sections. These localized geometric features concentrate and distribute stresses in controlled patterns that reduce stress concentration points, thereby improving fatigue resistance while using standard fastener installation procedures
Solution Approach 2:
The flange geometry is designed to pre-distribute loads across the contact surfaces before the dynamic loads are applied. The toe and heel surfaces create an initial favorable stress distribution pattern that prepares the connection to better withstand subsequent cyclic loading, improving fatigue performance
3Ease of operation
If standard flanged connections are used, then the assembly can be straightforward, but fasteners loosen due to vibration caused by wind and water waves
Solution Approach 1:
The flange design incorporates specific geometric features at localized regions (toe and heel surfaces) that create favorable friction characteristics and load distribution. These localized features increase the frictional resistance to fastener loosening without complicating the overall assembly procedure
Solution Approach 2:
The curved contact surfaces created by the toe and heel sections increase the contact area and improve the mechanical interlocking between flanges. This geometric configuration enhances the resistance to vibration-induced fastener loosening while maintaining straightforward assembly procedures
4Strength
If flanges with complex geometries are used to improve contact stress distribution, then the structural strength increases, but the manufacturing complexity and cost increase
Solution Approach 1:
Rather than redesigning the entire flange structure, the invention applies geometric modifications only to specific localized regions (the toe and heel surface sections). This approach achieves improved contact stress distribution while minimizing the overall complexity increase and keeping manufacturing processes relatively simple
Solution Approach 2:
The flange contact surface is segmented into distinct functional zones: the toe surface section, the heel surface section, and intermediate regions. This segmentation allows each zone to be optimized for its specific function while keeping the overall design manageable and manufacturable
Data Source
AI summary
A set of flanges, an installation including the set of flange and a method for providing the installation are disclosed. The set of flanges includes a first annular flange with a first front side and a second annular flange with a second front side. Each flange includes a plurality of through holes for mounting the flanges with the first side facing the second side. The first and the second sides are shaped such that the annular toe surface section of the first front side is adapted to provide an annular toe contact region with the annular toe surface section of the second front side and the annular heel surface section of the first front surface is adapted to provide annular heel contact region with the annular heel surface section of the second front side whereby an intermediate annular gap is provided between the annular toe contact region and the annular heel contact region.