Wind Turbine Blade Root Inserts and Mounting Flange

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Solution Overview

Problem

Wind turbine blades made from composite materials face structural integrity issues at the blade root portion, leading to deformations during storage and manufacturing, which can result in misalignment and vulnerability of the attachment to the hub, necessitating additional reinforcement like metal flanges and fasteners that add complexity and stress.

Innovation Solution

Incorporating a plurality of inserts with protruding ends embedded in the blade root portion and a mounting flange with complementary holes, forming a rigid structure that reduces deformations and ensures proper alignment and attachment without additional fastening means, allowing for faster manufacturing and reduced storage-related issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a metal flange with small bolts or screws is used to reinforce the blade root, then the mounting surface becomes more even and alignment is improved, but the device complexity increases and local stresses are introduced that may shorten blade lifetime

Engineering Contradiction:
Improvemounting surface alignmentVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The mounting flange is integrated directly into the blade root portion as a single composite structure, eliminating the need for separate reinforcement components. The flange and blade root form a unified structure that maintains alignment without requiring additional bolts or screws, thus reducing device complexity while preserving manufacturing precision.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The mounting flange is constructed using composite materials that match the blade root portion, allowing the flange to be manufactured as an integral part of the blade. This composite construction provides the necessary structural integrity and alignment stability without introducing metal fasteners that would create local stresses and increase complexity.

Inventive Principle:
Principle #40Composite materials

2Productivity

If the blade is removed from the mould quickly to accelerate manufacturing, then productivity increases, but the blade root portion deforms due to incomplete curing and shrinkage

Engineering Contradiction:
Improvemanufacturing speedVSAvoidblade root dimensional stability
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The mounting flange is designed with pre-established geometric features and reinforcement structures that maintain the blade root's dimensional stability during the curing process. The flange's structural design prevents deformation even when the blade is removed from the mould before complete curing, allowing early demoulding without sacrificing precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The blade manufacturing process utilizes controlled curing parameters and gradual curing progression. The blade is allowed to cure to a sufficient degree in the mould before removal, at which point the mounting flange provides structural support to prevent further deformation. This parameter control enables faster manufacturing while maintaining blade root precision.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If additional small bolts or screws are used to attach the mounting flange, then the attachment robustness is improved, but the blade root portion is subjected to local stresses that may reduce its lifetime

Engineering Contradiction:
Improveattachment robustnessVSAvoidblade lifetime
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The mounting flange is integrated into the blade root portion as a single unified structure, eliminating the need for separate fastening components. This integration removes the sources of local stress concentration that would be introduced by bolts or screws, thereby preserving blade lifetime while maintaining attachment robustness through the unified structural design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The mounting flange and blade root are constructed from compatible composite materials that bond seamlessly, creating a unified structure without requiring mechanical fasteners. This composite integration eliminates stress concentrations at fastener holes and prevents the local damages that would reduce blade lifetime, while maintaining reliable attachment capability.

Inventive Principle:
Principle #40Composite materials

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

The rigid structure formed by the inserts and mounting flange minimizes deformations, ensures proper alignment, and enhances the robustness of the blade root, facilitating a secure and efficient attachment to the hub, thereby extending the lifespan of the blades and simplifying the manufacturing process.

Implementation Method 1

the resin may not be fully cured yet and the blades may still be relatively soft

Methodology Applied
Scientific EffectCuring: Photopolymerisation

Implementation Method 2

composite materials are well-known for shrinking upon curing

Methodology Applied
Scientific EffectShrinkage: Thermal Contraction

Data Source

PatentEP2674612B1Blade for a wind turbine
Publication Date: 2016.10.05 ALSTOM RENEWABLE TECH
  • EP2674612B1 patent drawingFigure 1
  • EP2674612B1 patent drawingFigure 2~3
  • EP2674612B1 patent drawingFigure 4

AI summary

A blade for a wind turbine comprising a blade root portion is described. The blade root portion defines an mounting surface for coupling to a hub or extender of the wind turbine and comprises a plurality of first holes provided with an insert, the blade root portion further comprises a mounting flange arranged in the periphery of the mounting surface and provided with second holes, wherein the inserts comprise a first end embedded in the blade root portion and a second end opposite to said first end, the second end protruding beyond the mounting surface of the blade root portion, and wherein the second ends are fitted in the second holes of the mounting flange and the mounting flange is attached to the blade by means of the inserts. Furthermore, a wind turbine rotor comprising such a blade is described. Methods of manufacturing half a wind turbine blade and a whole wind turbine blade are also described.