Split Core for Radar-Absorbing Wind Turbine Blades

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Solution Overview

Problem

Existing wind turbine blades face challenges in incorporating radar-absorbing materials (RAM) due to varying core thickness, which affects radar absorption performance, and require core materials that can drape to conform to curvature while maintaining functional layer separation and integrity.

Innovation Solution

A split core arrangement with a uniformly thick first core layer and a varying thickness second core layer, along with a functional interlayer, ensures consistent RAM performance across the blade, and hinge portions in the core layers facilitate draping without disrupting the interlayer functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the core thickness is varied across the blade for structural reasons, then the structural performance is improved, but the radar absorption performance deteriorates due to inconsistent separation between RAM layers

Engineering Contradiction:
Improvestructural performanceVSAvoidradar absorption performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The core is divided into two separate layers: a first core layer with substantially uniform thickness that maintains consistent separation between RAM layers for reliable radar absorption, and a second core layer with varying thickness that provides structural adaptation to different blade regions. This segmentation allows each layer to independently fulfill its specific function without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the core have different thickness characteristics tailored to local requirements. The first core layer maintains uniform thickness throughout to ensure consistent RAM functionality, while the second core layer varies its thickness locally to meet structural demands of different blade regions (root vs tip, leading edge vs trailing edge).

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the core is made drappable to conform to blade curvature, then the ease of manufacture is improved, but the integrity of embedded functional layers deteriorates due to disruption of layer separation

Engineering Contradiction:
Improvedraping capabilityVSAvoidlayer separation integrity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The core is segmented into two layers that can be independently configured. The first core layer with uniform thickness provides a stable platform that maintains RAM layer separation during draping, while the second core layer can be optimized for draping performance. This segmentation allows draping capability without compromising functional layer integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first core layer acts as an intermediary between the RAM layers and the varying structural requirements. By maintaining uniform thickness, it mediates the draping process while preserving the critical separation distance between RAM absorbing and reflecting layers, thus protecting functional integrity during manufacturing.

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

The solution allows for consistent radar absorption performance across the blade, simplifies RAM design, and enhances the ability of the core to conform to complex curvatures while maintaining the integrity of embedded functionalities like RAM and optical fibers.

Implementation Method 1

Incorporating RAM into blades ensures that the resulting blades have a reduced radar signature

Methodology Applied
Scientific EffectRadar absorption: Absorption (EM radiation)

Implementation Method 2

the radar reflecting layer 18 may suitably comprise a carbon cloth

Methodology Applied
Scientific EffectRadar reflection: Reflection

Data Source

PatentEP2421700B1Improvements in or relating to composite structures
Publication Date: 2016.12.21 QINETIQ LTD
  • EP2421700B1 patent drawingFigure 1a~1b
  • EP2421700B1 patent drawingFigure 2a~3b
  • EP2421700B1 patent drawingFigure 4a~4c

AI summary

A split core for a composite structure is described. The split core includes a first core layer, a second core layer, and a functional interlayer disposed between the first and second core layers. The first core layer separates the functional interlayer from a functional layer of the composite structure and/or from an outer surface of the composite structure. The thickness of the first core layer is substantially uniform across the composite structure and the distance between the functional interlayer and the functional layer and/or the outer surface of the composite structure is substantially constant across the composite structure.