Thin Thermostructural Composite Part Using Spread Multilayer Fabric
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Solution Overview
Problem
Existing methods for producing thin thermostructural composite material parts, such as those for aviation and space applications, face challenges in achieving uniform fiber preforms with sufficient mechanical properties and smooth surface finishes, often resulting in material loss and residual porosity due to the need for thick initial fiber structures and irregular surfaces.
Innovation Solution
A method involving multilayer weaving with a high number of layers and spreading yarns to reduce thickness while maintaining a fiber volume ratio of 25-45%, using yarns weighing at least 200 tex, and densifying with a ceramic or carbon matrix to produce parts with thicknesses less than 2 mm, which preserves mechanical properties and reduces macroporosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional fiber preform fabrication methods are used to produce thin parts, then material loss increases and surface irregularities occur, but achieving uniform fiber distribution and sufficient mechanical properties becomes difficult
Solution Approach 1:
The patent changes the fiber volume ratio parameter to a specific range (25-45%) optimized for thin parts, and controls the number of fabric layers relative to thickness (ratio ≥ 4). These parameter changes enable uniform fiber distribution while minimizing material loss and achieving sufficient mechanical properties in thin composite parts.
2Length of stationary object
If the number of fabric layers is reduced to achieve thin parts, then thickness decreases, but mechanical strength and surface quality deteriorate
Solution Approach 1:
The patent optimizes the fiber volume ratio to 25-45% and establishes a minimum ratio between the number of layers and thickness (≥ 4), ensuring that even with reduced layer counts for thin parts, sufficient mechanical strength is maintained through improved fiber distribution and reduced porosity.
Solution Approach 2:
The patent uses composite fabric structures combining different fiber orientations (warp and weft layers) to maintain mechanical strength in thin parts. The multilayer composite structure provides enhanced strength-to-thickness ratio while achieving smooth surfaces and uniform fiber distribution.
3Strength
If fiber volume ratio is increased to improve mechanical properties, then strength improves, but pore accessibility for densification decreases
Solution Approach 1:
The patent identifies and applies an optimal fiber volume ratio range (25-45%) that balances mechanical properties with manufacturability. Within this range, sufficient fiber content provides strength while adequate porosity remains for matrix infiltration during densification processes.
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
This approach enables the production of thin composite parts with improved mechanical properties and surface smoothness, reducing material loss and porosity, and achieving thicknesses as low as 1 mm while maintaining a sufficient number of layers for strength.
Implementation Method 1
CVI densification is performed by placing the fiber preform in an enclosure and admitting a reaction gas into the enclosure under determined conditions in particular of pressure and temperature so that the gas diffuses into the preform and enables a deposit of the matrix material to be obtained as a result of one or more ingredients of the gas decomposing or as a result of a reaction between a plurality of its ingredients
Implementation Method 2
polymerizing and pyrolyzing the resin in order to obtain a carbon or ceramic residue
Data Source
AI summary
A thermostructural composite material part including carbon or ceramic fiber reinforcement densified by a matrix having at least one thin portion in which: the thickness of the part is less than 2 mm, or indeed less than 1 mm; the fiber reinforcement is made as a single thickness of multilayer fabric made of spread yarns having a weight of not less than 200 tex; the fiber volume ratio lies in the range 25% to 45%; and the ratio between the number of layers of the multilayer fabric and the thickness in millimeters of the part is not less than four.