Segmented Tower Flange Assembly for High-Load Connections
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Solution Overview
Problem
The limited load-bearing capacity of conventional L-flange connections in wind turbine towers restricts the height of tower structures, and the XL-flange, while offering improved load transfer, results in increased material costs and complex manufacturing due to larger forgings and machining waste.
Innovation Solution
The design of a flange connection using two separate segments, a primary bolt circle with inclined openings forming an X-flange configuration and a secondary bolt circle for an L-section, allowing for reduced material usage and simpler manufacturing by minimizing machining waste and enabling non-destructive testing from below, thus reducing the size of the forging and weld neck.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If XL-flange is used to improve load-bearing capacity, then load transfer capability is improved, but material cost and manufacturing complexity increase due to larger forgings
Solution Approach 1:
The flange is divided into two separate segments (first flange-segment and second flange-segment) that can be manufactured independently from smaller forgings and then assembled together. This segmentation allows each segment to be forged at a reduced size, significantly decreasing the amount of raw material required and reducing machining waste, while still achieving the high load-bearing capacity of an XL-flange through the combined structure with primary and secondary bolt circles
2Strength
If XL-flange is used to improve load-bearing capacity, then load transfer capability is improved, but manufacturing complexity increases due to elaborate manufacturing process
Solution Approach 1:
By segmenting the flange into two separately manufacturable parts, the manufacturing process becomes less complex. Each segment can be forged and machined independently using standard processes, avoiding the need for a single large, complex forging operation. The segments are then assembled using conventional connection methods (bolts, welding, or adhesive), simplifying the overall manufacturing workflow while maintaining high load-bearing capacity
Solution Approach 2:
The two flange-segments are manufactured separately in advance using optimized, simpler processes before final assembly. This preliminary manufacturing of separate components allows for better process control, reduced machining waste, and easier quality inspection, particularly enabling non-destructive testing from below the first flange-segment, thereby reducing overall manufacturing complexity while achieving the desired structural performance
3Strength
If L-extension is added to create XL-flange, then load-bearing capacity is improved, but forging width increases requiring larger raw material
Solution Approach 1:
The L-extension structure is achieved by combining two separately forged segments rather than creating one large monolithic forging. The first flange-segment contains the primary bolt circle and the second flange-segment contains the L-extension with secondary bolt circle. This segmentation allows each segment to be forged at a manageable width, significantly reducing the size of raw material required compared to a single large XL-flange forging, while still providing the full load-bearing capacity through the combined structure
4Strength
If larger forging is used for XL-flange, then load-bearing capacity is improved, but machining waste increases due to height restrictions
Solution Approach 1:
By dividing the flange into two segments, each with reduced dimensions, the amount of material that needs to be machined away is significantly reduced. The first flange-segment and second flange-segment can be forged closer to their final dimensions since they don't need to accommodate the full height and width requirements of a single large XL-flange. This segmentation directly reduces machining waste while maintaining the load-bearing capacity through the combined structure with both primary and secondary bolt circles
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances the load-bearing capacity comparable to T-flanges while reducing material costs and manufacturing complexity, allowing for efficient load transfer and assembly without external access requirements, particularly beneficial for offshore installations.
Implementation Method 1
a welding neck adapted to connect the flange to a tower section
Implementation Method 2
an intermediate layer arranged between the first flange-segment and the second flange-segment
Data Source
AI summary
Provided is a flange for connecting to a complementary flange, and wherein the flange includes a first flange-segment and a second flange-segment, wherein a) the first flange-segment includes a primary bolt circle including an annular arrangement of inclined openings; and a first annular connection face adapted to lie against a complementary second annular connection face of the second flange-segment; and b) the second flange-segment includes on two opposite sides annular connection faces adapted to lie against complementary annular connection faces; a primary aperture circle including an annular arrangement of openings; and a second body section with a secondary bolt circle including an annular arrangement of openings. Also provided is respective flange-segments, a method for manufacturing such flange and a tower construction.