X-L-Flange Segmented Bolt Circle for Wind Turbine Tower Strength

Solution Overview

Problem

The limited load-bearing capacity of commonly used L-flange connections in wind turbine towers restricts the tower structure's height and stability, especially with the increasing length of rotor blades.

Innovation Solution

The development of an improved flange connection, referred to as the X-L-flange, which features an essentially planar annular connection face with a primary bolt circle comprising alternately inclined openings for enhanced load transfer and a secondary bolt circle for temporary connections to interim structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a T-flange is used to increase load-bearing capacity, then the strength of the flange connection is improved, but the assembly and lifetime servicing cost increases due to requiring external access

Engineering Contradiction:

Improveload-bearing capacityVSAvoidassembly cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The flange is segmented into two distinct body sections: a first body section with a primary bolt circle for permanent tower section connections, and a second body section with a secondary bolt circle for temporary handling connections. This segmentation allows each section to serve its specific function optimally without requiring external access for all operations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flange is designed with multi-functionality by incorporating both primary and secondary bolt circles, enabling it to serve dual purposes: permanent structural connections through the primary bolt circle and temporary handling/transport connections through the secondary bolt circle. This eliminates the need for separate external access points while maintaining high load-bearing capacity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Strength

If a T-flange is used to increase load-bearing capacity, then the strength of the flange connection is improved, but the assembly and lifetime servicing cost increases due to requiring external access

Engineering Contradiction:

Improveload-bearing capacityVSAvoidaccess requirement

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The flange is segmented into two distinct body sections: a first body section with a primary bolt circle for permanent tower section connections, and a second body section with a secondary bolt circle for temporary handling connections. This segmentation allows each section to serve its specific function optimally without requiring external access for all operations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flange is designed with multi-functionality by incorporating both primary and secondary bolt circles, enabling it to serve dual purposes: permanent structural connections through the primary bolt circle and temporary handling/transport connections through the secondary bolt circle. This eliminates the need for separate external access points while maintaining high load-bearing capacity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If an L-flange is used to maintain internal access advantage, then the ease of operation is improved, but the load-bearing capacity is limited

Engineering Contradiction:

Improveinternal accessVSAvoidload-bearing capacity

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The flange is segmented into two distinct body sections: a first body section with a primary bolt circle for permanent tower section connections, and a second body section with a secondary bolt circle for temporary handling connections. This segmentation allows each section to serve its specific function optimally without requiring external access for all operations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention adds a dimensional aspect by introducing a second body section with a secondary bolt circle that is spatially separated from the primary bolt circle. This creates a multi-dimensional connection system where internal access is maintained for primary connections while external handling is enabled through the secondary circle, effectively resolving the access-strength contradiction.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12297655B2Flange

Publication Date: 2025.05.13 SIEMENS GAMESA RENEWABLE ENERGY AS

AI summary

A flange is provided for connection to a complementary flange, and wherein the flange includes an annular connection face to lie against a complementary annular connection face of the complementary flange; a first body section with a primary bolt circle including an annular arrangement of inclined openings to receive a set of fasteners for connecting the flange to the complementary flange and a second body section with a secondary bolt circle including an annular arrangement of openings to receive a set of fasteners for connecting the flange to an interim structure. Also provided is a method of handling a cylindrical tower section equipped with such a flange.