Thermoplastic Elastomer Repair Patch for Wind Turbine Blade Erosion

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Solution Overview

Problem

Existing methods for repairing erosion protection layers on rotor blades and aircraft wings are inefficient, requiring frequent suspension of operations and resulting in economic losses, as they often necessitate the replacement of entire protection tapes, which can be prone to erosion themselves, and do not effectively address localized damage.

Innovation Solution

A method involving the removal of damaged protection layers, optional reconstruction of the composite substrate, application of a primer and polymer solutions, and application of a thermoplastic elastomer repair patch that melts and covers the damaged area, forming a new protection layer without the need for adhesive layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the entire protection tape is replaced to repair erosion damage, then the erosion protection is restored, but the repair time and operational downtime increase significantly

Engineering Contradiction:
Improveerosion protectionVSAvoidrepair time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The protection system is divided into modular segments: the base protection tape and the overlay repair patch. This allows only the damaged portion to be repaired with an overlay patch rather than replacing the entire protection tape system, significantly reducing repair time while maintaining erosion protection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of performing complete replacement (excessive action), the method applies partial repair by placing an overlay patch only on the damaged area. This partial action restores protection where needed without the time cost of full replacement.

Inventive Principle:
Principle #16Partial or excessive action

2Ease of manufacture

If polyurethane tapes with pressure-sensitive adhesive are used for protection, then the tape can be easily applied, but the tapes themselves become prone to erosion and require frequent replacement

Engineering Contradiction:
Improveapplication easeVSAvoiderosion resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The solution uses a composite structure consisting of a base protection tape layer and an overlay repair patch layer. The overlay patch is made from thermoplastic elastomer material that provides superior erosion resistance, while the combination maintains ease of application through the overlay process.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The method changes the material parameters of the repair layer by using thermoplastic elastomer overlay material with different properties than the base polyurethane tape. This material parameter change provides enhanced erosion resistance while maintaining application feasibility.

Inventive Principle:
Principle #35Parameter changes

3Loss of time

If localized repair is performed instead of complete replacement, then the repair time is reduced, but the repaired area may not achieve the same erosion protection as the original layer

Engineering Contradiction:
Improverepair timeVSAvoiderosion protection uniformity
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The overlay repair patch is designed to be homogeneous with the surrounding original protection layer in terms of material composition and protective properties. Both layers are made from compatible thermoplastic elastomer materials that provide uniform erosion resistance across the entire surface, including the repaired area.

Inventive Principle:
Principle #33Homogeneity

Solution Approach 2:

The repair method merges the overlay patch material with the surrounding original protection layer through heat activation and pressure application. This merging creates a unified, homogeneous protective surface where the repaired area becomes indistinguishable from the original layer in terms of erosion protection.

Inventive Principle:
Principle #5Merging (Combining)

4Strength

If adhesive layers are used to attach repair patches, then the patches can be secured to the surface, but the adhesive layers add complexity and potential failure points

Engineering Contradiction:
Improveattachment strengthVSAvoidrepair structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The method extracts and eliminates the adhesive layer from the repair structure. Instead of using adhesive to attach the overlay patch, the patch is secured through direct mechanical bonding achieved by heating and pressing the thermoplastic elastomer material, simplifying the overall repair structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The chemical bonding mechanism of adhesive is replaced with a thermal-mechanical bonding system. The overlay patch is attached through heat activation that melts the thermoplastic elastomer, followed by mechanical pressure to secure the bond, eliminating the need for separate adhesive materials and application steps.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 method allows for quick, cost-effective, and efficient repair of localized damage on rotor blades and aircraft wings, maintaining the same erosion protection properties as the original layer, reducing downtime and operational losses.

Implementation Method 1

applying heat so that the polymer tape melts and covers the damaged area, thereby forming a protection layer

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

applying a polymer solution, preferably in at least one organic solvent

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3403812B1Repair strip and process for wind turbine leading edge protection tape
Publication Date: 2019.11.20 3M INNOVATIVE PROPERTIES CO

AI summary

A method is described for repairing the surface of rotor blades or aircraft wings, comprising (a) a composite substrate; and (b) a protection layer having at least one area of at least partial damage, the method comprising (i) removing at least part of the damaged part of the protection tape; (ii) optionally, reconstructing the surface of damaged composite substrate; (iii) optionally, applying primer solution to the surface of the composite substrate; (iv) optionally, applying a polymer solution, preferably in at least one organic solvent; (v) applying a repair patch of a polymer tape comprising at least one thermoplastic elastomer onto at least of a part of the composite surface; (vi) applying heat so that the repair patch of a polymer tape melts and covers the damaged area, thereby forming a protection layer or applying a repair solution, preferably in at least one organic solvent, so that the repair patch of a polymer tape at least partially dissolves and covers the damaged area.