Unidirectional Reinforcement with Transverse Flow Passages

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Solution Overview

Problem

Current unidirectional reinforcement methods face challenges in resin permeability and transverse stability, leading to inefficient resin flow and potential micro-cracks, especially in complex shapes like wind turbine blades, due to issues with stitching, weaving, and chemical bonding, which affect the strength and fatigue properties of the final product.

Innovation Solution

A novel unidirectional reinforcement with thin discrete flow passage forming means arranged transverse to the rovings, secured by additional yarns, enhances resin permeability and air escape during vacuum infusion, improving wet-out distance and fatigue properties by maintaining straight fibers and minimizing kinks and micro-cracks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If stitching or weaving is used to anchor rovings in unidirectional reinforcement, then transverse stability is improved, but resin permeability deteriorates and micro-cracks form

Engineering Contradiction:
Improvetransverse stabilityVSAvoidresin permeability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent removes the stitching and weaving elements from the unidirectional reinforcement structure. By extracting these transverse anchoring elements, the reinforcement allows direct resin permeability without the harmful effects of stitches creating micro-cracks or blocking resin flow paths.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a porous structure by spacing the rovings apart using spacers, forming channels that allow resin to flow through the reinforcement. This porous arrangement provides both transverse stability and excellent resin permeability, eliminating the need for stitching while maintaining structural integrity.

Inventive Principle:
Principle #31Porous materials

2Stability of the object's composition

If chemical bonding is used to anchor rovings, then transverse stability is improved, but resin flow is blocked and wet-out distance is reduced

Engineering Contradiction:
Improvetransverse stabilityVSAvoidresin flow speed
Core Design Contradiction:
Stability of the object's compositionVSSpeed

Solution Approach 1:

The patent eliminates chemical bonding agents and their associated blockers from the reinforcement structure. By removing these chemical anchoring mechanisms, the resin can flow freely through the reinforcement without encountering chemical barriers that would slow down wet-out.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The spacer-based porous structure provides mechanical support and transverse stability without blocking resin flow. The porous channels created by spacers facilitate rapid resin penetration throughout the reinforcement, achieving both stability and fast wet-out distance.

Inventive Principle:
Principle #31Porous materials

3Ease of operation

If traditional stitching is used to hold rovings together, then handling stability is improved, but resin permeability deteriorates and wet-out time increases

Engineering Contradiction:
Improvehandling stabilityVSAvoidwet-out time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent removes stitching elements from the reinforcement structure. By extracting these mechanical fasteners, the reinforcement achieves handling stability through the spacer-based porous structure, which also allows rapid resin flow without the time-consuming wet-out delays caused by stitches.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The porous structure formed by spacers provides both handling stability during manufacturing and rapid resin permeability during curing. The open channels allow resin to penetrate quickly, reducing wet-out time while the spaced arrangement maintains structural integrity for easy handling.

Inventive Principle:
Principle #31Porous materials

4Stability of the object's composition

If hot-melt coated yarns are used for weaving, then transverse stability is improved, but local disturbance in matrix curing occurs

Engineering Contradiction:
Improvetransverse stabilityVSAvoidmatrix curing
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent eliminates hot-melt coated yarns from the reinforcement structure. By removing these coated elements, the reinforcement provides transverse stability through spacers without introducing foreign materials that would cause local disturbances in the matrix curing process.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The spacer-based porous structure provides transverse stability without using hot-melt coated materials. This approach allows uniform matrix curing throughout the laminate by eliminating local chemical disturbances that would otherwise occur at the locations of coated yarns.

Inventive Principle:
Principle #31Porous 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 solution significantly increases resin flow speed and distance, reduces micro-cracks, and enhances the strength and fatigue properties of the laminate, allowing for more efficient production of complex shapes without the drawbacks of traditional stitching or chemical bonding.

Implementation Method 1

bonded to each other by a thermoplastic and/or thermoset binder

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

when wetting-out a stack of reinforcements, the impregnation of the reinforcement with resin

Methodology Applied
Scientific EffectVacuum: Vacuum

Data Source

PatentEP2875937B1A unidirectional reinforcement, a method of producing a unidirectional reinforcement and the use thereof
Publication Date: 2021.03.03 VITRULAN COMPOSITES OY
  • EP2875937B1 patent drawingFigure 1a~2
  • EP2875937B1 patent drawingFigure 3~4
  • EP2875937B1 patent drawingFigure 5

AI summary

The present invention relates to a unidirectional reinforcement and a method of producing a unidirectional reinforcement. The unidirectional reinforcement of the present invention may be used in all such applications where high quality and strength is required. The unidirectional reinforcement (20) of the invention comprises transversely arranged thin discrete flow passage forming means (40) for ensuring good resin flow properties in a direction transverse to the direction of the unidirectional rovings. The thin discrete flow passage forming means (40) are secured on the unidirectional rovings by means of additional yarns (42) running on the thin discrete flow passage forming (40) means and transverse thereto.