Composite Partial Plies with Through-Thickness Vents
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Solution Overview
Problem
Existing composite manufacturing processes face challenges in efficiently removing entrapped gas from localized reinforcement plies, leading to porosity issues, especially when doubler plies do not extend to the edge of the laminate, as conventional methods like edge breathing and extended vacuum dwells are ineffective.
Innovation Solution
Incorporating a preform design with full-length and partial plies, where vents are created through the partial plies to allow direct extraction of air, volatiles, or resin using a release film with perforations and vacuum application, reducing the distance for air to escape and eliminating the need for extended vacuum dwells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods like edge breathing and extended vacuum dwells are used, then processing time is extended, but air removal effectiveness from trapped doubler plies remains insufficient
Solution Approach 1:
The invention segments the laminate structure by introducing discrete vent channels through the doubler plies, dividing the continuous air extraction path into multiple localized exit points. This segmentation allows air to be removed directly from trapped regions without relying on slow diffusion to edges, effectively solving the air removal problem while avoiding extended processing times.
Solution Approach 2:
The invention extracts air directly from the interior of the laminate by creating vent channels that provide direct pathways from trapped air pockets to the external environment. This extraction method eliminates the need for extended vacuum dwells required by conventional edge breathing methods, resolving the contradiction between air removal effectiveness and processing time.
2Productivity
If vents are created through partial plies, then air extraction efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The vent channels are incorporated into the laminate structure during the layup process itself, rather than being added as a separate post-processing step. This preliminary action integrates the air extraction functionality into the manufacturing process, improving air extraction efficiency without significantly increasing overall manufacturing complexity.
Solution Approach 2:
The invention uses an intermediary material or structure (such as a venting layer or channel-forming element) that facilitates air extraction through the partial plies. This intermediary component simplifies the creation of vent channels compared to direct mechanical drilling or cutting, thereby improving air extraction efficiency while managing manufacturing complexity.
3Manufacturing precision
If extended vacuum dwells are used, then air removal is attempted, but porosity issues persist in trapped ply regions
Solution Approach 1:
The vent channels provide direct extraction pathways for air and volatiles from trapped ply regions during the curing process. This direct extraction prevents porosity formation by removing gases before they can become entrapped in the resin matrix, achieving superior porosity control without requiring extended vacuum dwells that would increase processing time.
Solution Approach 2:
The vent channels enable continuous air removal throughout the curing process, maintaining effective gas extraction from trapped regions throughout the entire resin infusion and curing cycle. This continuous action ensures consistent porosity control without the need for prolonged vacuum holding periods, reducing overall processing time while maintaining manufacturing precision.
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 method effectively reduces porosity by directly extracting gases through the laminate thickness, enabling efficient air removal from trapped doubler plies without the need for autoclave processing, thus saving costs and processing time.
Implementation Method 1
Vacuum is applied to a preform having a vent and a plurality of sets of partial plies, the vent extending through the plurality of sets of partial plies. At least one of air, volatiles, or resin is drawn out of the plurality of sets of partial plies through the vent and into a breather.
Implementation Method 2
Debulk is performed on the preform such that at least one of air, volatiles, or resin is drawn from the plurality of sets of partial plies through the vent and the perforations of the release film
Data Source
AI summary
Methods of forming a composite structure from a preform with a vent are presented. A preform comprises a plurality of sets of full length plies, a plurality of sets of partial plies alternating with the plurality of sets of full length plies, and a vent extending through the plurality of sets of partial plies.