Curable prepregs with surface openings
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Solution Overview
Problem
Fiber-reinforced polymer composites face challenges in removing trapped gases during consolidation, leading to porosity issues that affect their mechanical properties, as traditional methods like edge breathers are inefficient in removing all gases.
Innovation Solution
The development of curable prepregs with resin-impregnated woven fabrics treated to create specific surface openings, allowing for enhanced gas removal through these openings during consolidation and curing, facilitating the escape of gases and vacuum penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional consolidation methods are used, then the composite can be manufactured, but trapped gases remain causing porosity
Solution Approach 1:
The prepreg is designed with a porous structure containing interconnected voids that serve as gas storage and transport channels. These pores allow gases to move from trapped locations to the surface for removal during consolidation, directly addressing the porosity problem while maintaining structural integrity.
Solution Approach 2:
The invention introduces a third dimension (depth) for gas removal by creating subsurface pores and channels within the prepreg structure. Instead of relying solely on surface-level gas escape, gases can now be removed through interconnected pathways extending throughout the volume of the prepreg, significantly improving gas removal efficiency.
2Productivity
If edge breathers are used to remove gases, then some gas removal is achieved, but the process is slow and incomplete
Solution Approach 1:
The gas removal system is segmented into multiple pathways: surface pores for direct escape, subsurface pores for intermediate storage and transport, and interconnected channels for distributing gases to various exit points. This segmentation allows simultaneous gas removal from multiple locations, dramatically increasing efficiency compared to single-point edge breather methods.
Solution Approach 2:
The porous structure acts as an intermediary system between trapped gases and the external environment. The interconnected pores and channels provide a dedicated transport network that facilitates efficient gas migration from the interior of the prepreg to the surface, where gases can be removed by vacuum or pressure differential.
3Strength
If the matrix resin is dense, then structural integrity is maintained, but gas movement is inhibited causing trapped gases
Solution Approach 1:
The matrix resin exhibits different properties at different locations: in the bulk material, it maintains high density and structural integrity, while in the pore regions, it forms a less dense, more permeable structure. This local variation in quality allows the matrix to simultaneously provide strength and facilitate gas movement through the porous pathways.
Solution Approach 2:
The matrix resin structure is designed as a composite of dense regions (providing strength) and porous regions (providing gas transport pathways). This composite structure combines the benefits of both dense and porous materials, maintaining overall structural integrity while enabling efficient gas removal throughout the prepreg volume.
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 significantly reduces porosity in the final composite, improving its mechanical properties by effectively removing gases from within prepregs and between layers, resulting in composites with residual porosity of less than 1% volume.
Implementation Method 1
enhanced gas removal through these openings during consolidation and curing, facilitating the escape of gases
Implementation Method 2
facilitating the escape of gases and vacuum penetration
Data Source
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. Furthermore, the location of the openings is specific to the weave pattern of the fabric.