Flexible Wind Blade Root Bulkhead Flange Ovalization

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Solution Overview

Problem

Wind turbine blades experience significant ovalization, leading to potential damage at the blade root and bulkhead connection, with existing rigid attachment methods prone to failure, additional material costs, and secondary sealing issues.

Innovation Solution

A flexible flange made of layered materials such as epoxy resin, biaxial glass, and a rim structure that absorbs forces and maintains a durable seal between the blade root and bulkhead, eliminating the need for secondary seals and additional material, while being resistant to rot and oil damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid bulkhead attachment is used to ensure structural support, then the blade root and bulkhead connection strength is improved, but the damage to the attachment joint from ovalization increases

Engineering Contradiction:
Improveblade root and bulkhead connection strengthVSAvoidattachment joint durability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The bulkhead attachment transitions from a rigid static connection to a dynamic flexible connection that can adapt to ovalization movements. The flexible flange material allows the bulkhead to move with the blade root during ovalization while maintaining attachment, preventing joint damage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The attachment method changes from rigid to flexible by altering the physical parameters of the connecting material. The flexible flange material has different stiffness and elasticity parameters compared to rigid connections, allowing it to accommodate ovalization-induced deformations without failing.

Inventive Principle:
Principle #35Parameter changes

2Strength

If steel rods or composite brackets are used to connect the bulkhead to the blade root, then the connection strength is improved, but the device complexity and maintenance requirements increase

Engineering Contradiction:
Improvebulkhead to blade root connection strengthVSAvoidnumber of parts and sealing requirements
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The flexible flange integrates multiple functions into a single component: structural attachment, sealing, and accommodation of ovalization movement. This eliminates the need for separate steel rods, composite brackets, and secondary sealing systems, reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The flexible flange serves multiple purposes simultaneously: it provides structural connection between the bulkhead and blade root, seals the interface to prevent debris ingress, and accommodates ovalization-induced movements. This multi-functionality replaces multiple specialized components.

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

3Force

If the bulkhead is rigidly attached to the blade wall to resist high loads, then the resistance to ovalization forces is improved, but the cost of additional material and risk of joint failure increase

Engineering Contradiction:
Improveresistance to ovalization forcesVSAvoidmaterial cost and manufacturing complexity
Core Design Contradiction:
ForceVSEase of manufacture

Solution Approach 1:

The flexible flange uses a thin flexible material to resist ovalization forces, replacing the need for thick rigid reinforcements. The flexible material distributes and absorbs forces through elastic deformation, achieving force resistance with minimal material thickness and cost.

Inventive Principle:
Principle #30Flexible shells and thin films

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 flexible flange provides cost-effective stress relief and sealing, preventing damage from ovalization and unwanted pollution, and supports the blade root and bulkhead without requiring extra material or secondary sealing, ensuring durability and reliability.

Implementation Method 1

A flexible flange made of layered materials such as epoxy resin, biaxial glass, and a rim structure that absorbs forces

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2235364B1Flexible wind blade root bulkhead flange
Publication Date: 2013.10.23 GENERAL ELECTRIC CO
  • EP2235364B1 patent drawingFigure 1
  • EP2235364B1 patent drawingFigure 2~3
  • EP2235364B1 patent drawingFigure 4~5

AI summary

A flexible flange (300) for a blade root wall (302) allows movement of the blade root (209) toward and away from the bulkhead (304). The flexible flange provides flexibility and support for the blade wall and also provides a sealant, thereby protecting the machinery in the hub (110). The flexible flange has a top portion (306) configured to be secured to a blade root wall, a bottom portion (310) configured to be secured to a bulkhead (304) and an angled portion (308) configured to offset the top portion from the bottom portion, a gap (312) being between the blade root wall and the bottom portion to allow for movement of the blade root wall toward and away from the bulkhead.