Surface-Opened Prepregs for Faster Debulking and Lower Porosity
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Solution Overview
Problem
Fiber-reinforced polymer composites face challenges in removing trapped gases during fabrication, leading to porosity and reduced mechanical properties due to the matrix resin inhibiting gas movement, which prolongs debulk time and increases costs.
Innovation Solution
Curable prepregs with surface openings created by thermal treatment of resin-impregnated woven fabrics allow for enhanced gas removal during consolidation, reducing debulk time and porosity through specific weave pattern-based openings that facilitate gas flow and vacuum penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional resin-impregnated prepregs are used, then the fabric is substantially impregnated with resin, but gases become trapped inside the prepreg and between layers, resulting in porosity and requiring extended debulk time
Solution Approach 1:
The patent applies preliminary action by creating surface openings in the prepreg before the debulking process. The openings are formed by partially impregnating the fabric with resin and then applying heat to create controlled surface openings that allow gases to escape during subsequent debulking, eliminating the need for extended debulk time while maintaining structural integrity
Solution Approach 2:
The patent utilizes porous materials by creating a controlled porous structure on the prepreg surface. The surface openings act as gas escape pathways, allowing trapped gases to vent during debulking and curing processes, thereby reducing porosity and eliminating the need for prolonged debulk time
2Strength
If traditional resin-impregnated prepregs are used, then the fabric is substantially impregnated with resin, but porosity develops in the final composite, negatively affecting mechanical properties
Solution Approach 1:
The patent applies porous materials by creating controlled surface openings in the prepreg that serve as gas escape pathways. These openings allow gases to vent during debulking and curing, preventing porosity formation in the final composite and thereby maintaining high mechanical properties
Solution Approach 2:
The patent applies the extraction principle by removing the harmful element (trapped gases) through surface openings. The openings provide designated escape routes for gases, extracting them from the composite structure before curing, thereby preventing porosity and preserving mechanical integrity
3Object-generated harmful factors
If edge breathers are used to remove trapped gases, then vacuum is applied to draw out gases, but the process is slow and cannot substantially remove all trapped gases
Solution Approach 1:
The patent applies dimensionality change by transitioning from edge-only gas removal (2D surface approach) to multi-dimensional gas removal. Surface openings distributed across the prepreg create three-dimensional gas escape pathways throughout the material, enabling simultaneous gas removal from multiple locations and dramatically increasing debulk speed
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 use of surface openings in prepregs significantly reduces porosity and debulk time, resulting in improved mechanical properties and reduced production costs by enabling more efficient gas removal during composite fabrication.
Implementation Method 1
Each curable prepreg is a resin-impregnated, woven fabric that has been treated to create an array of openings in at least one major surface
Implementation Method 2
heat may be applied to cause the matrix resin to flow, enabling consolidation of the prepreg layers
Implementation Method 3
edge breathers may be employed to apply vacuum to the edge of prepregs in order to draw out gases from the sides of prepreg layers
Data Source
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AI summary
Curable prepregs possessing enhanced ability for the removal of gases from within prepregs and between prepreg plies in a prepreg layup prior to and/or during consolidation and curing. Each curable prepreg is a resin-impregnated, woven fabric that has been subjected to a treatment to create an array of openings in at least one major surface. The location of the openings is specific to the weave pattern of the fabric. Furthermore, when these prepregs are laid up and subjected to a debulking process to form a composite part, a shorter debulking time can be achieved as compared to using prepregs without the same surface openings.