Wind Turbine Blade Shell Preforms for Steep-Mold Wrinkle Reduction

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Solution Overview

Problem

Existing methods for manufacturing wind turbine blade shells face challenges with fibre roving handling, particularly in steep mold slopes, leading to material sliding and undesired wrinkles, which affect structural integrity and are costly.

Innovation Solution

A method involving preformed sheets made of fibre rovings joined by a binding agent, allowing for easier handling and reduced material costs, with improved stability and resin infusion channels, using Vacuum Assisted Resin Transfer Molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If glass fibre material is placed in a mold with steep slopes for manufacturing large blades, then the blade structure can be formed, but the fibre material slides down the mold walls causing wrinkles and structural weakness

Engineering Contradiction:

Improveshell structure qualityVSAvoidfibre material handling

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The fibre material is pre-impregnated with resin in a controlled environment before molding, creating a prepreg that maintains its shape and position. This preliminary impregnation prevents sliding during placement in steep mold slopes, eliminating wrinkles while maintaining manufacturing precision

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The fibre material's physical state is changed from dry to resin-impregnated, altering its adhesion properties and structural integrity. The resin impregnation increases the material's cohesion and friction against the mold surface, preventing sliding down steep slopes during the molding process

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If traditional molding processes are used for large blades, then manufacturing experience is available, but material costs are high and handling is difficult

Engineering Contradiction:

Improvehandling efficiencyVSAvoidmaterial cost

Core Design Contradiction:

Ease of manufactureVSQuantity of substance

Solution Approach 1:

Fibre mats are pre-cut and pre-impregnated with resin to exact specifications before delivery to the molding site. This preliminary preparation eliminates the need for expensive on-site material handling equipment and reduces waste, lowering material costs while improving handling efficiency through standardized, pre-configured components

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The complex mechanical handling systems traditionally required for large blade manufacturing are replaced by the chemical bonding properties of resin-impregnated fibre mats. The sticky resin allows materials to be held and positioned without expensive clamping or securing mechanisms, reducing equipment costs and simplifying operations

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Stability of the object's composition

If fibre rovings are used without binding agent, then material flexibility is high, but stability during handling and molding is poor

Engineering Contradiction:

Improvefibre roving stabilityVSAvoidpreform structure

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The fibre roving is combined with a binding agent to create a composite preform structure. The binding agent acts as a matrix holding the fibres in their intended configuration, providing stability during handling and molding while maintaining the flexibility needed for conforming to mold shapes. This composite approach achieves both stability and adaptability

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 results in cost savings of up to 30-45% and reduces irregularities in the shell laminate, enhancing structural stability and handling efficiency.

Implementation Method 1

A vacuum is typically used to draw epoxy resin material into a mold

Methodology Applied

Scientific EffectVacuum: Vacuum

Implementation Method 2

resin is forced to flow through the fibres using a vacuum pump

Methodology Applied

Scientific EffectPressure difference: Pressure Gradient

Implementation Method 3

each preformed sheet comprises a mixture of fibre rovings and a binding agent, wherein the fibre rovings are at least partially joined together by means of the binding agent

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3423266B1Method of molding a shell part of a wind turbine blade

Publication Date: 2025.07.30 LM WIND POWER AS

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AI summary

The present invention relates to a method of molding a shell part of a wind turbine blade comprising the steps of providing a mold (64) comprising a mold cavity (66) with a root end (68) and an opposing tip end (70), arranging one or more preformed sheets (72a, 72b, 72c) in the mold cavity (66), wherein each preformed sheet comprises a mixture of fibre rovings (82) and a binding agent, wherein the fibre rovings are at least partially joined together by means of the binding agent, and injecting the one or more preformed sheets (72a, 72b, 72c) with a resin to mold the shell part. The present invention also relates to a shell part of a wind turbine blade obtainable by said method, to a preformed sheet for use in said method and to a method of manufacturing said preformed sheet.