Mock Leno Weave Fibrous Structure for Composite Thickness Variation
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Solution Overview
Problem
The production of composite material parts with varying thickness, such as aeronautical engine blades, faces challenges including complex manufacturing processes, high material losses, and difficulties in achieving homogeneous mechanical properties due to the use of high fiber content in thickened areas, which complicates the formation of blade roots and increases production costs.
Innovation Solution
A fibrous structure with a Mock Leno weave texture is used, featuring a multilayer three-dimensional weave with varying thickness, where the Mock Leno weave provides an airy structure for matrix infiltration and maintains a non-zero spacing between warp yarns, allowing for controlled fiber distribution and reduced fiber content in thickened areas, eliminating the need for inserts and enhancing mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If high count yarns are used to increase fiber content in thickened parts, then thickness variation is improved, but porosity and matrix infiltration are worsened
Solution Approach 1:
The fibrous structure is divided into distinct zones: thickened parts with Mock Leno weave texture for volume control, and standard density regions for structural integrity. This segmentation allows each zone to perform its specific function without compromising the other.
Solution Approach 2:
The Mock Leno weave texture is applied locally only in thickened parts where volume increase is needed, while other regions maintain standard weave density. This local application of different weave patterns optimizes both thickness variation and porosity control in their respective zones.
2Shape
If inserts are used to form bulb-shaped root portions, then thickness variation is improved, but manufacturing complexity and cost are worsened
Solution Approach 1:
The Mock Leno weave texture is integrated directly into the preform structure during weaving, merging the thickness control function with the base material formation. This eliminates the need for separate inserts and their associated handling, positioning, and bonding operations.
Solution Approach 2:
The Mock Leno weave texture inherently provides the bulb-shaped geometry through its woven structure, allowing the preform to self-form the required shape without requiring additional forming tools or inserts. The weave pattern itself serves the dual purpose of structural reinforcement and geometric formation.
3Loss of substance
If Mock Leno weave texture is used in thickened parts, then matrix infiltration is improved, but fiber content control is worsened
Solution Approach 1:
The Mock Leno weave texture changes the physical parameters of the fibrous structure by creating a more open, grid-like pattern with larger inter-yarn spaces. This parameter change increases porosity and facilitates matrix infiltration while the localized application controls overall fiber content.
Data Source
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AI summary
The invention relates to a fibrous structure (200) comprising a plurality of weft layers and of warp layers bound together by the multi-layer three-dimensional weaving, the fibrous structure (200) comprising at least first (203) and second (204) parts which are adjacent in the warp direction, the first part (203) having, in a direction perpendicular to the warp and weft directions, a thickness that is greater than the thickness of the second part (204), characterized in that the first part (203) comprises, at its heart (2031), at least one fibrous texture (ML) obtained by three-dimensional weaving of the warp and weft layers in the form of a Mock Leno weave, the said at least one texture (ML) being present between facings (2032; 2033) which are present at the surface of the first part (203) and being connected to the facings (2032; 2033) by warp threads (C3; C16) belonging to the said facings which are diverted locally into the said texture.