3D Fibrous Preform Thermoforming with Heat-Sensitive Polymer
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Solution Overview
Problem
Existing methods for producing 3D fibrous preforms face challenges in maintaining structural integrity and preventing deformation during resin infiltration, particularly for complex shapes and large thicknesses, as they often result in slippage and structural deformations, and previous solutions like electrostatic powdering are not flexible or adaptable to non-conductive fibers and lack controlled binder distribution.
Innovation Solution
A 3D fibrous preform is created using multilayer weaving with warp and weft yarns coated with a heat-sensitive polymer, allowing for controlled bonding at intersections and debonding zones to maintain structure and facilitate uniform resin penetration, enabling the preform to be thermoformed into complex shapes without pressure and ensuring consistent polymer distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multilayer weaving is used to create 3D fibrous preforms with large thickness, then the structural integrity and shape complexity are improved, but slippage and structural deformations occur during resin infiltration
Solution Approach 1:
The patent applies preliminary action by coating yarns with heat-sensitive polymer before weaving, and performing thermoforming before resin infiltration. This pre-bonding of intersections and pre-shaping of the preform prevents slippage and deformation during the subsequent resin infiltration process, maintaining dimensional accuracy while achieving complex 3D structures.
Solution Approach 2:
The patent utilizes parameter changes by employing heat-sensitive polymer that changes its bonding properties with temperature. During thermoforming, the polymer transitions from unbonded to bonded state, providing temporary flexibility during shaping and then locking the structure in place to prevent deformation during resin infiltration.
2Stability of the object's composition
If electrostatic powdering is used to stabilize preforms, then binder distribution is improved, but the method is not adaptable to non-conductive fibers and lacks flexibility
Solution Approach 1:
The patent replaces electrostatic powdering with a method based on heat-sensitive polymer that changes bonding state with temperature. This approach is universally applicable to both conductive and non-conductive fibers, providing adaptability while maintaining preform stability through controlled thermal bonding at yarn intersections.
Solution Approach 2:
The heat-sensitive polymer acts as an intermediary substance that enables bonding between fibers without requiring electrostatic properties. This intermediary approach works with all fiber types, providing versatility while achieving the desired preform stability through thermal activation rather than electrostatic mechanisms.
3Quantity of substance
If resin infiltration pressure is applied to penetrate the preform core, then resin penetration is improved, but yarn slippage and structural deformation increase
Solution Approach 1:
The patent applies preliminary action by pre-bonding yarn intersections with heat-sensitive polymer before resin infiltration. This pre-stabilization allows subsequent resin infiltration under pressure to proceed without causing yarn slippage or structural deformation, maintaining dimensional accuracy while achieving complete resin penetration.
4Stability of the object's composition
If yarns are coated with heat-sensitive polymer and thermoformed, then controlled bonding at intersections is achieved, but the process complexity increases
Solution Approach 1:
The patent uses parameter changes through heat-sensitive polymer that transitions from unbonded to bonded state with temperature. This provides precise control over bonding at yarn intersections during thermoforming, achieving the desired stability while the added process step is offset by the simplicity of thermal activation compared to alternative bonding methods.
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 preform is stabilized, easily manipulable, and allows for uniform resin infiltration, reducing mechanical performance issues and enabling the production of composite parts with precise geometries and complex shapes while maintaining fiber volume ratio consistency.
Implementation Method 1
the plurality of warp yarns and/or weft yarns bear a heat-sensitive polymer on a surface of the yarns... The fibrous structure is thermoformed at a temperature above the softening point of the polymer
Implementation Method 2
above the softening point of the polymer followed by cooling, whereby the warp yarns and the weft yarns are bonded to their intersections by polymer
Implementation Method 3
allows for uniform resin penetration
Data Source
AI summary
The preform made of a 3D fibrous structure comprises at least 3 layers (1, 2) of weft yarns and/or warp yarns, the structure being woven as a single part by multilayer weaving between a plurality of layers of warp yarns and a plurality of layers of weft yarns. It comprises a predetermined distribution of points of intersection of warp yarn and weft yarn that are bonded by polymer. The polymer represents a mass of less than or equal to 10%. The preform comprises at least one thermoformed portion in which the warp yarns and the weft yarns are bonded at the intersections thereof by polymer where at least one of the warp and/or weft yarns bears polymer.