Triaxial Textile Armature Void Reduction via Segmented Axial Layers
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Solution Overview
Problem
Existing braiding machines for manufacturing triaxial composite materials face challenges in achieving uniform thickness and optimal fiber distribution, leading to suboptimal mechanical performance and increased costs due to complex mechanisms and high fiber voids.
Innovation Solution
A braiding process using a machine with two rows of adjacent notched wheels and three rows of tubes, where bias yarns pass through odd and even intervals of axial yarns without crossing, ensuring a constant thickness and smooth yarn paths, with axial yarns in the central layer being larger than those in side layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If regular braiding machines are used to manufacture triaxial fabric with equal fiber in three directions, then the fabric can be produced, but the axial yarns create large voids between them and the surface cannot be fully recovered by both axial and bias yarns simultaneously
Solution Approach 1:
The invention segments the axial yarns into multiple independent layers (first axial layer, second axial layer, third axial layer) that are disposed at different positions and orientations. This segmentation allows each layer to be optimized independently, with the first and third layers providing axial coverage while the second layer fills voids between them, achieving complete surface recovery without large voids.
Solution Approach 2:
The invention transitions from a single-layer axial yarn structure to a multi-layer three-dimensional architecture. By stacking axial yarn layers at different positions (first axial layer at bottom, second axial layer in middle, third axial layer at top) and combining with bias yarns in +60° and -60° directions, the structure achieves complete volumetric coverage and eliminates voids.
2Quantity of substance
If the thickness of axial yarns is doubled to cover the surface, then more fiber can be placed in axial direction, but the fabric structure becomes complex with alternate ribbons and multiple layers, reducing manufacturing efficiency
Solution Approach 1:
Instead of using fewer thick axial yarns, the invention segments the axial fiber content into multiple thinner yarns arranged in separate layers. The first, second, and third axial layers each contain multiple axial yarns that work together to provide sufficient axial fiber content while maintaining a manageable, non-complex structure that is easier to manufacture.
Solution Approach 2:
The invention applies different yarn configurations to different local regions and layers. Each axial layer has its own optimized yarn arrangement, and the bias yarns are strategically placed to link specific layers together. This localized optimization achieves high axial fiber content without requiring uniform thick yarns throughout the entire structure.
3Reliability
If multilayer braiding machines with concentric rows of notched wheels and gears are used, then reliable functioning is achieved, but the bias yarn crossings create many axial voids that cannot be filled, decreasing fiber volume ratio
Solution Approach 1:
The invention segments the axial reinforcement into multiple separate layers (first, second, and third axial layers) that are strategically positioned to fill the voids created by bias yarn crossings. Each layer serves a specific function: the first and third layers provide axial coverage, while the second layer specifically targets and fills the axial voids, achieving high fiber volume ratio despite the inherent voids from bias yarn intersections.
Solution Approach 2:
The invention converts the harmful effect of bias yarn crossings (which create axial voids) into a beneficial opportunity. Instead of trying to eliminate the voids created by the reliable multilayer braiding process, the design strategically places the second axial layer to fill these voids, transforming the defect into a feature that demonstrates the effectiveness of the multi-layer architecture.
4Ease of manufacture
If axial yarns are introduced inside tubes disposed in the center of each wheel, then the braiding process can be simplified, but the machine cannot create high quality fiber armature due to unavoidable axial voids from bias yarn crossings
Solution Approach 1:
The invention maintains the simple tube-based axial yarn introduction system but segments the axial reinforcement into multiple layers. The first, second, and third axial layers are introduced through the tube system at different stages or positions, allowing each layer to be optimized for its specific function while using the same simple manufacturing approach.
Solution Approach 2:
The invention adds the vertical dimension with multiple axial layers while maintaining the simple horizontal tube introduction system. By stacking axial yarn layers at different heights/positions (first layer at bottom, second layer in middle, third layer at top) and combining with bias yarns, the simple manufacturing process achieves high-quality fiber armature that fills all voids.
Data Source
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AI summary
Triaxial textile armature for making high quality composite materials comprising a central layer of axial yarns and at least two side layers of axial yarns. The side layers of axial yarns are placed on opposite sides with regard to the central layer of axial yarns. The axial layers are crosslinked by two directions of bias yarns. The bias yarns of the first direction pass through the central layer of axial yarns in even intervals between axial yarns. The bias yarns of the second direction pass through the central layer of axial yarns in odd intervals between axial yarns. An elementary pattern is formed of twelve axial yarns arranged in three layers, wherein the yarns of the central layer are placed in quincunxes with regard to the axial yarns of the side layers, linked by two crossed sets of N bias yarns each, wherein each bias yarn passes alternatively over six axial yarns and under six axial yarns while crossing 2*N yarns of the other bias direction. The invention also relates to a process for making such armature and a composite material part comprising such armature