Non-stitched Fiber Material for Wind Turbine Blade Manufacturing
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Solution Overview
Problem
Existing methods for manufacturing wind turbine blades using vacuum-assisted resin transfer molding (VARTM) face challenges with air permeability issues due to stitching yarns, which can lead to insufficient vacuum pressure and 'hovering glass' phenomena, especially in complex mold geometries.
Innovation Solution
A non-stitched fiber material bonded with an adhesive, featuring zigzag-shaped beads to enhance air tightness and generate sufficient pressure drops, preventing 'hovering glass' and ensuring the layup adheres to the mold surface, even when the mold is inverted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If stitching yarn is used to hold fiber rovings together, then the fiber material can be manufactured and handled, but air permeability increases and vacuum pressure becomes insufficient
Solution Approach 1:
The patent removes the stitching yarn from the fiber material structure entirely. Instead of using yarn to bind rovings, the invention uses adhesive applied directly to the roving surface, which then bonds adjacent rovings together without creating penetrating stitches that compromise vacuum integrity.
Solution Approach 2:
The patent introduces adhesive as an intermediary substance between rovings to provide binding functionality. The adhesive layer acts as a mediator that holds rovings together while maintaining the airtightness of the composite structure, replacing the mechanical stitching function with a chemical bonding mechanism.
2Ease of manufacture
If stitching yarn is used to bind fiber rovings, then the fiber material can be assembled, but openings form between rovings reducing air tightness
Solution Approach 1:
The patent extracts the stitching yarn element that creates harmful openings. By eliminating the yarn-based binding system, the invention removes the source of cavities and channels that allow air leakage between rovings during vacuum processing.
Solution Approach 2:
The adhesive serves as an intermediary that fills the gaps between rovings rather than creating channels through them. The adhesive material bonds the roving surfaces together while maintaining continuity of the fiber mass, preventing air penetration paths.
3Manufacturing precision
If vacuum is applied to force layup against mold surface, then mold conformity is achieved, but hovering glass occurs in complex geometries
Solution Approach 1:
The patent employs a disposable adhesive layer that is applied to the roving surface and then consumed in the bonding process. This adhesive layer provides the necessary bonding function during manufacturing and is then integrated into the final composite structure, eliminating the need for removable stitching elements.
Solution Approach 2:
The adhesive acts as an intermediary bonding agent that ensures complete contact between the layup and mold surface by eliminating air pockets and hovering glass. The adhesive material flows into and fills any voids, ensuring intimate contact between the fiber reinforcement and mold geometry.
4Reliability
If non-woven fiber glass material with low air permeability is used, then vacuum pressure is improved, but stitching yarn creates local constrictions and deformations
Solution Approach 1:
The patent removes the stitching yarn that causes local constrictions and deformations. By eliminating the yarn-based binding system, the invention prevents the mechanical distortion and localized compression that occurs where yarn penetrates and binds the fiber structure.
Solution Approach 2:
The adhesive serves as a gentle intermediary that bonds rovings without creating localized stress concentrations. Unlike stitching yarn that penetrates and constricts fibers, the adhesive layer provides distributed bonding pressure that maintains the natural shape and alignment of fiber bundles.
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 provides improved air tightness and pressure drops sufficient to counteract gravity, ensuring accurate mold conformity and secure adhesion of the fiber layup, enhancing the manufacturing process for wind turbine blades.
Implementation Method 1
The non-stitched fiber material comprises a plurality of fibers bonded together by an adhesive to improve the air tightness of the non-stitched fiber material
Implementation Method 2
a vacuum ensures that said layers 9, 10 are firmly positioned against the mold 8
Implementation Method 3
The non-stitched fiber material is configured to produce a pressure drop sufficient to force the layup of fiber material against the mold surface when vacuum is applied
Implementation Method 4
When the mold is inverted, gravity may cause the mold and/or the fiber material to deform
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
A non-stitched fiber material (20), a method for manufacturing a component (5) for a wind turbine and an apparatus for manufacturing a non-stitched fiber material are provided. The non-stitched fiber material (20) is configured to produce a pressure drop sufficient to force a layup (9) of fiber material against the mold surface (7) when vacuum is applied to the space between the non-stitched fiber material (20) and the mold surface (7), the non-stitched fiber material (20) comprising a plurality of fibers (22) bonded together by an adhesive (23,30). The method is advantageous in that it avoids openings as found in stitched fiber materials, which allows air through flow. Thus, the non-stitched fiber material has a low air permeability.