Wind Turbine Blade Shell Thickness Sensing With Eddy Currents

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Solution Overview

Problem

The existing ultrasound thickness measurement methods for wind turbine blades are not sufficiently precise, leading to blades being scrapped even though they meet specifications, due to smearing and reflections from structural components, resulting in a minimum error of 2%.

Innovation Solution

A method using an electrically conductive element and a magnetic field generator to induce an Eddy current, allowing for precise thickness measurement of fibre-reinforced wind turbine blade components through induced magnetic field signals, which can be converted to thickness or fibre volume fraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional multi-component resin system is used for manufacturing wind turbine blades, then the structural integrity and fatigue life are improved, but the manufacturing complexity and production time increase significantly

Engineering Contradiction:
Improvestructural integrity and fatigue lifeVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The resin system is segmented into distinct functional components: a polyol component and an isocyanate component, each stored separately in different cartridges. This segmentation allows each component to be optimized independently while simplifying the overall manufacturing process by enabling separate storage and controlled mixing, thereby reducing contamination risks and extending shelf life without compromising structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The polyol and isocyanate components are prepared and stored in advance in separate cartridges with pre-installed mixing mechanisms. This preliminary action eliminates the need for on-site mixing preparation and ensures that components are ready for immediate injection into the mold, reducing manufacturing complexity and production time while maintaining reliability.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a conventional multi-component resin system is used for manufacturing wind turbine blades, then the structural integrity and fatigue life are improved, but the production time increases due to multiple mixing and injection steps

Engineering Contradiction:
Improvestructural integrity and fatigue lifeVSAvoidproduction time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The mixing and injection operations are merged into a single integrated step. The polyol and isocyanate components are mixed and injected into the mold simultaneously through a unified injection mechanism, eliminating sequential processing steps. This merging reduces production time while maintaining the structural integrity achieved by using the multi-component resin system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The injection process maintains continuous flow of both resin components throughout the mold cavity without interruption or pause for separate mixing steps. This continuous action ensures complete mold filling in a single operation, reducing production time while preserving the structural quality benefits of the polyol-isocyanate resin system.

Inventive Principle:
Principle #20Continuity of useful action

3Reliability

If separate storage and mixing of polyol and isocyanate components is implemented, then contamination is reduced and shelf life is extended, but the device complexity increases

Engineering Contradiction:
Improvecontamination controlVSAvoidstorage and mixing system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A mixing chamber serves as an intermediary element between the separate polyol and isocyanate storage cartridges and the mold cavity. This intermediary receives both components, performs controlled mixing, and then injects the combined resin into the mold. This approach maintains contamination control through separate storage while managing device complexity by using a single integrated mixing and injection mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If a single-component resin system is used for manufacturing wind turbine blades, then the manufacturing process is simplified and production time is reduced, but the fatigue life and structural integrity deteriorate

Engineering Contradiction:
Improvemanufacturing simplicity and production speedVSAvoidfatigue life and structural integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The resin system parameters are changed by using a reactive polyol component that undergoes chemical transformation upon mixing with isocyanate. This parameter change enables the resin to achieve superior structural properties and fatigue resistance that single-component systems cannot provide, while the rapid mixing and injection process maintains manufacturing efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The final cured resin forms a composite material structure resulting from the chemical reaction between polyol and isocyanate components. This composite structure provides enhanced structural integrity and fatigue life compared to single-component resins, while the one-step mixing and injection process maintains manufacturing simplicity and production speed.

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 method provides more precise thickness measurements, reducing the number of false negatives and ensuring blades meet specifications without unnecessary scrapping, with minimal impact on blade strength.

Implementation Method 1

a mixing device for mixing a polyol component and an isocyanate component

Methodology Applied
Scientific EffectMechanical mixing:

Implementation Method 2

an injection device for injecting the polyol component and the isocyanate component into a mold

Methodology Applied
Scientific EffectPressure-driven injection:

Data Source

PatentEP3969266B1Manufacturing a wind turbine blade shell part
Publication Date: 2026.04.29 LM WIND POWER AS
  • EP3969266B1 patent drawingFigure 1
  • EP3969266B1 patent drawingFigure 2
  • EP3969266B1 patent drawingFigure 3

AI summary

The present invention relates to a method for manufacturing a wind turbine blade part. The method comprises providing one or more wind turbine blade components including a wind turbine blade component comprising a fibre material element, an electrically conductive element, a magnetic field generator for generating an Eddy current in the electrically conductive element; arranging the electrically conductive element, the magnetic field generator, and the fibre material element such that at least a part of the fibre material element is positioned between the electrically conductive element and the magnetic field generator; generating an Eddy current in the electrically conductive element using the magnetic field generator; generating, using a magnetic sensor, a signal representing a magnetic field induced by the generated Eddy current, and forming the wind turbine blade part by assembling the wind turbine blade components.