Variable Thickness Composite Fibrous Structure with Segmented Zones
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Solution Overview
Problem
Existing methods for producing composite material parts with variable thickness, such as aeronautical engine blades, face issues with fiber content porosity and unbalanced warp/weft ratios, leading to inadequate mechanical properties and dimensional limitations in the thick central portions.
Innovation Solution
A 3D or multilayer fibrous structure with a separation zone allowing for strands of greater size than warp threads, providing extra thickness while maintaining homogeneous fiber content and warp/weft ratios, and allowing flexibility in strand number and size within the unbinding zone, enabling varied dimensions and shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the yarn count is increased in thicker sections to reduce thickness reduction during compression forming, then the thickness control is improved, but the fiber content becomes too high which increases porosity and prevents adequate matrix access to the core
Solution Approach 1:
The fibrous structure is segmented into distinct zones: a first zone with standard yarn count, a second zone with increased yarn count for thickness, and a third zone with reduced yarn count. This segmentation allows each zone to have optimized fiber content for its specific function, preventing excessive porosity in thick sections while maintaining thickness control.
Solution Approach 2:
Different zones of the fibrous structure have different yarn counts tailored to local requirements. The second zone has higher yarn count for thickness, while the third zone has lower yarn count to ensure adequate matrix access and proper fiber content, creating local quality variations that resolve the contradiction between thickness control and mechanical properties.
2Length of stationary object
If the number of warp threads is increased in the central section to achieve desired thickness, then the thickness is improved, but the warp-to-weft ratio becomes unbalanced which reduces mechanical properties in lateral sections
Solution Approach 1:
The structure is divided into zones with different warp thread densities. The central second zone has increased warp threads for thickness, while the lateral third zones have reduced warp threads to maintain proper warp-to-weft ratio balance, ensuring mechanical properties are preserved in all sections.
Solution Approach 2:
Each zone has locally optimized warp thread count: the central zone prioritizes thickness with higher warp density, while lateral zones prioritize mechanical properties with balanced warp-to-weft ratios. This local quality approach allows thickness variation without compromising overall structural integrity.
3Length of stationary object
If high-count yarns are used locally to increase fiber content, then the thickness is improved, but the porosity network becomes insufficient which prevents adequate matrix constituent access to the core
Solution Approach 1:
The fibrous structure is segmented into zones with different yarn counts. The third zone specifically uses reduced yarn count to create sufficient porosity and pore connectivity, ensuring matrix constituents can adequately access the core while the second zone maintains higher yarn count for thickness requirements.
Solution Approach 2:
Different zones have locally optimized yarn counts that balance thickness and matrix infiltration needs. The third zone's reduced yarn count creates optimal porosity for matrix access, while the second zone's increased yarn count provides thickness, with each zone's properties tailored to its specific functional requirements.
Data Source
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AI summary
A fibrous reinforcing structure for a part made of composite material woven as a single piece by three-dimensional or multi-layer weaving between a plurality of layers of weft filaments (202) and a plurality of layers of warp filaments (201). The fibrous structure comprises, in a transverse direction (DT): - first and second portions (210, 211) in each of which all the layers of warp filaments (201) are associated with one another by weft filaments (202) of the plurality of layers of weft filaments, the first and second portions respectively forming first and second longitudinal edges of the fibrous structure, and - a third portion (212) present between the first and second portions (210, 211), the third portion comprising a dissociated region (214) delimiting a housing (220) inside the fibrous structure (200) extending over a determined distance in the longitudinal direction (DC) and in the transverse direction (DT). The dissociated region separates a first skin (221) from a second skin (222), each of the skins comprising part of the layers of warp filaments associated with one another by weft filaments of the plurality of weft filaments. Strands (230, 231, 232) extend inside the housing (220) in the longitudinal direction (DC), the strands having a size greater than or equal to the size of the warp filaments (201) of the plurality of layers of warp filaments so as to give the third portion (212) a thickness greater than the thickness of the first and second portions.