Compressible Bonding Composite for Wind Turbine Blade Fairings

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Solution Overview

Problem

The existing methods for attaching aerodynamic fairings to wind turbine blades using adhesives often result in distortion of the fairings and tools due to high pressure, and are costly for larger blades, as they require stiff and expensive tools to prevent distortion, and also face issues with excess adhesive causing problems during use.

Innovation Solution

A method using a composite with a void volume of at least 20% comprising an uncured matrix and a compressible solid, which applies sufficient pressure for bonding without distorting the fairings, and a three-dimensional fibrous structure with a low-density layer to manage pressure and adhesion, allowing for a structural connection that resists buckling and reduces weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If adhesive is applied to bond fairings to spar cap, then structural connection is achieved, but high pressure causes distortion of fairings and tools

Engineering Contradiction:
Improvebonding strengthVSAvoidaerodynamic surface distortion
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The patent introduces a porous compressible material layer between the fairing and spar cap that absorbs excess adhesive and distributes pressure uniformly. This porous material compresses during bonding to accommodate the adhesive while maintaining low pressure on the fairing, preventing distortion while ensuring strong structural connection.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent changes the physical state and compressibility parameters of the bonding interface by introducing a compressible material layer. This layer transitions from a uncompressed state with high void volume to a compressed state during bonding, allowing pressure regulation that prevents fairing distortion while achieving adequate bond strength.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If stiff tools are used to prevent fairing distortion during bonding, then manufacturing precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvefairing positioning accuracyVSAvoidtooling complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces expensive, complex, reusable stiff tools with a disposable porous compressible material layer that performs the same function of preventing distortion. This single-use material eliminates the need for investing in and maintaining expensive tooling infrastructure while achieving the same manufacturing precision.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If excess adhesive is used to ensure complete bonding, then bonding reliability is improved, but harmful factors increase due to adhesive breaking off and clogging drainage holes

Engineering Contradiction:
Improvebonding reliabilityVSAvoidadhesive breakoff and drainage hole clogging
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The porous compressible material acts as an adhesive reservoir and distributor, absorbing excess adhesive and releasing it gradually during compression. This ensures complete bonding coverage while preventing adhesive accumulation that could break off and clog drainage holes, thus maintaining bonding reliability while eliminating harmful effects.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The porous compressible material serves as an intermediary between the adhesive and the fairing structure. It mediates the adhesive application process by controlling adhesive distribution, preventing both insufficient bonding and excessive adhesive accumulation that causes harmful breakoff and clogging.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach allows for a strong, lightweight structural connection between the spar cap and fairing without distorting the aerodynamic surface, reduces the need for expensive tools, and minimizes excess adhesive issues, enabling efficient assembly of wind turbine blades of any length.

Implementation Method 1

adhering the fairing to the spar cap as the matrix is cured

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

compressing the deformable solid so that the composite substantially occupies a space between the spar cap and the fairing

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

curing the matrix to maintain the compressible solid in its compressed state

Methodology Applied
Scientific EffectCuring: Photopolymerisation

Data Source

PatentEP2900456B1A method of forming a structural connection between a spar cap and a fairing for a wind turbine blade
Publication Date: 2020.08.05 BLADE DYNAMICS LTD
  • EP2900456B1 patent drawingFigure 1A
  • EP2900456B1 patent drawingFigure 1B
  • EP2900456B1 patent drawingFigure 1C

AI summary

A method of forming a structural connection between a spar cap (14) and an aerodynamic fairing (12). A composite comprising an uncured matrix and a compressible solid is applied between the spar cap and fairing and is then compressed and cured to adhere the fairing to the spar cap. The cured matrix composite has a void volume of at least 20%. The high void volume means that as the fairing is compressed into place and compresses the composite, it has space in which to deform so as not to place undue stress on the fairing and to produce a lightweight connection.