Polyurethane Layer Structures for Wind Turbine Rotor Blades

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Solution Overview

Problem

The production of rotor blades for wind power plants using conventional resin-based fibre-reinforced plastics is labor-intensive, time-consuming, and costly due to lengthy curing times and high labor requirements, limiting productivity and quality control.

Innovation Solution

The use of polyurethane as the plastics material in a layer structure for rotor blades, including a release agent, gel coat, fibre layers treated with polyurethane, and optional spacer and film layers, with a reaction mixture of polyisocyanates and polyols, allowing for faster curing and reduced production time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional resin-based fibre-reinforced plastics are used for rotor blade production, then the structural strength and durability are ensured, but the curing time is very long (up to 12 hours) and productivity is severely restricted

Engineering Contradiction:
Improvestructural strengthVSAvoidproductivity
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent changes the chemical parameters of the matrix material from conventional slow-curing resins to fast-curing resin systems with modified chemistry. This parameter change reduces the curing time from up to 12 hours to significantly shorter durations, thereby increasing productivity while maintaining the structural strength requirements through appropriate resin formulation and fibre reinforcement design.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials consisting of fibre reinforcements (such as glass fibres, carbon fibres, or aramid fibres) combined with specially formulated fast-curing resin matrices. This composite structure ensures that the mechanical strength and durability requirements are met while the optimized resin system enables rapid curing, resolving the contradiction between strength and productivity.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If hand lamination process is used for rotor blade production, then investment in machinery is low and defects are easy to identify, but the process is very labour-intensive and manufacturing costs are very high

Engineering Contradiction:
Improveease of manufactureVSAvoidproductivity
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent replaces the manual mechanical hand lamination process with automated resin injection systems. The injection apparatus automatically delivers resin into the mould containing the fibre reinforcement, eliminating the need for manual resin application and consolidation. This substitution reduces labour intensity and manufacturing costs while improving productivity and consistency, though it requires investment in specialized equipment.

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

3Manufacturing precision

If prepreg technology is used for rotor blade production, then quality consistency is improved, but protection from volatile compounds requires significant safety outlay

Engineering Contradiction:
Improvequality consistencyVSAvoidvolatile compounds exposure
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent employs disposable dry fibre mats that are placed in the mould and then infused with resin through injection. This approach eliminates the need for pre-impregnated prepregs that contain volatile compounds. The dry fibre mats are inert and safe to handle, while the resin is injected and cures quickly, reducing exposure risks. This method maintains quality consistency through controlled resin injection while eliminating the safety hazards associated with volatile prepreg materials.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 approach significantly reduces demoulding time and enhances productivity by accelerating the curing process, enabling faster production of rotor blades with improved quality and lower costs.

Implementation Method 1

a reaction mixture of polyisocyanates and polyols, allowing for faster curing and reduced production time

Methodology Applied
Scientific EffectPolymerization: Chemical Bonding

Data Source

PatentUS11904582B2Use of layer structures in wind power plants
Publication Date: 2024.02.20 COVESTRO DEUTSCHLAND AG

AI summary

The invention relates to the use of layer structures in the production of rotor blades for wind power plants, and to rotor blades for wind power plants.