Wind Turbine Blade With Multiple Spar Caps for Fibre Alignment

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Solution Overview

Problem

The manufacturing of large wind turbine blades is challenging due to the alignment of fibre-reinforced materials in spar caps, which can lead to fibre misalignments and structural integrity issues, particularly in blades exceeding 70 meters in length.

Innovation Solution

A wind turbine blade design featuring a recess with varying widths and a transition region to minimize fibre misalignments, using two spar caps with different widths and a smooth transition, along with a method of manufacturing that includes gelcoat application to simplify the process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single wide spar cap is used to reduce manufacturing complexity, then ease of manufacture improves, but fibre misalignment and structural integrity deteriorate due to difficulty in aligning large continuous fibre sheets

Engineering Contradiction:
Improveease of manufactureVSAvoidfibre alignment precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The spar cap is divided into multiple segments (first spar cap and second spar cap) that can be manufactured and positioned separately. This segmentation allows each segment to be more easily aligned and bonded to the shell, reducing the complexity of handling large continuous fibre sheets while maintaining structural integrity through the bonding interfaces between segments

Inventive Principle:
Principle #1Segmentation

2Strength

If multiple spar caps with different widths are used to optimize structural performance, then strength and stability improve, but device complexity increases due to multiple components with varying dimensions

Engineering Contradiction:
Improvestructural strengthVSAvoidstructural complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The spar cap structure employs different widths at different locations along the blade span. The first spar cap has a first width and the second spar cap has a second width that is different from the first width. This local variation in dimensions optimizes the structural performance by providing appropriate stiffness and strength at different positions along the blade, where different spanwise locations experience different loading conditions

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If a recess with sudden width changes is used to accommodate spar caps, then manufacturing simplicity improves, but fibre misalignment increases at the transition regions

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidstructural reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The recess incorporates a transition region with a tapered width that gradually changes between the first region and the second region, rather than having sudden sharp transitions. This curved/tapered geometry allows fibre sheets to be laid up with gradual orientation changes, minimizing fibre misalignment and wrinkling while maintaining manufacturing feasibility

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP3643912B1A wind turbine blade with multiple spar caps
Publication Date: 2025.10.15 LM WIND POWER AS
  • EP3643912B1 patent drawingFigure 1
  • EP3643912B1 patent drawingFigure 2~3
  • EP3643912B1 patent drawingFigure 4a~5

AI summary

The present invention relates to wind turbine blade and a method of manufacturing the wind turbine blade. An aerodynamic shell is provided with a recess (70) at its inner surface, the recess (70) extending with-in the shell along a spanwise direction of the blade. A first region of the recess (70) has a first width and a second region of the recess (70) has a second width exceeding the first width. A transition region is provided between the first region and the second region of the re-cess. A first and a second spar cap (80, 82) are arranged within the shell.