Segmented Wind Turbine Rotor Blade Connection for Flapwise Load Transfer

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Manufacturing very long wind turbine rotor blades is constrained by manufacturing errors, transportation, installation, and structural limitations, particularly in segmented blades, which face challenges in transferring flapwise loads and require complex assembly for lightning protection.

Innovation Solution

A connecting interface using double-end stud bolts with aligned bores and threaded nuts, embedded in precast spar caps, effectively transfers flapwise and edgewise loads, and facilitates seamless assembly with integrated lightning protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rotor blades are manufactured as one piece, then manufacturing precision and structural integrity are improved, but manufacturing complexity and cost increase significantly for very long blades

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The rotor blade is divided into multiple segments that can be manufactured separately and then connected. This segmentation allows each segment to be manufactured with controlled complexity while the overall blade achieves the required length and structural integrity through proper connection interfaces.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If rotor blades are segmented, then transportation and installation costs are reduced, but the ability to transfer flapwise loads is limited

Engineering Contradiction:
Improvetransportation easeVSAvoidload transfer capability
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

Connection elements such as bolts, keys, or interlocking features are pre-integrated into the blade segment designs during manufacturing. This preliminary integration ensures that when segments are assembled, the load transfer paths are already established, enabling effective flapwise load transfer without requiring complex field assembly operations.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If conventional connection methods are used for segmented blades, then assembly is simplified, but complex assembly measures are required for lightning protection systems

Engineering Contradiction:
Improveassembly easeVSAvoidlightning protection assembly complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The connection interface between blade segments is designed to serve multiple functions: mechanical load transfer, structural alignment, and integration of lightning protection conductors. By incorporating conductor connection capabilities directly into the mechanical connection elements, the system eliminates separate assembly steps for lightning protection while maintaining structural integrity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3581790B1Wind turbine rotor blade
Publication Date: 2025.08.06 SIEMENS GAMESA RENEWABLE ENERGY AS
  • EP3581790B1 patent drawingFigure 1
  • EP3581790B1 patent drawingFigure 2
  • EP3581790B1 patent drawingFigure 3

AI summary

The invention describes a wind turbine rotor blade (2) comprising at least a first rotor blade segment (21) and a second rotor blade segment (22) connected by means of a connecting interface (1), which connecting interface (1) comprises a plurality of bores (11) formed in a connecting face (21F, 22F) of each rotor blade segment (21, 22), each bore (11) extending in a longitudinal direction (L) of the rotor blade (2) and terminating in a cavity (12) dimensioned to accommodate a threaded nut (13); a threaded nut (13) arranged in each of the plurality of cavities (12); and a plurality of double-end stud bolts (10), wherein a double-end stud bolt (10) comprises a shaped portion (100) formed between a first threaded end (101) and a second threaded end (102), which shaped portion (100) is shaped to engage with a bolt tightening means; and wherein the first threaded end (101) of each double-end stud bolt (100) is screwed into a threaded nut (13) held in a cavity (12) of the first rotor blade segment (21), and the second threaded end (102) of each double-end stud bolt (100) is screwed into a threaded nut (13) held in a cavity (12) of the second rotor blade segment (22). The invention further describes a method of manufacturing such a wind turbine rotor blade (2); a method of assembling a wind turbine rotor blade (2); and a wind turbine (3) comprising a number of such rotor blades (2).