Autoclave Composite Co-Curing Manifold System
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Solution Overview
Problem
Existing methods for co-curing composite skins and stiffeners in an autoclave require venting bladders through the vacuum bag, leading to potential leakage, pre-loading issues, and distortion of fiber stiffeners, as well as resin starvation.
Innovation Solution
A manifold system distributes autoclave pressure to bladders through vent tubes that pass through the vacuum bag outside the area overlying the parts, reducing the number of bag penetrations and avoiding pre-loading, with a reconfigurable design for different part assemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bladders are vented through the vacuum bag by placing holes in the bladders, then the internal pressure in the bladders can be equalized with autoclave pressure, but this increases the possibility of leakage into the bag, causes pre-loading of vent pipes, and leads to distortion of fiber stiffeners
Solution Approach 1:
The venting function is extracted from the bladder material itself and relocated to a separate vent tube that passes through the vacuum bag. This separates the pressure equalization function from the bladder structure, eliminating the need for holes in the bladder and preventing leakage and distortion issues.
Solution Approach 2:
A vent tube is introduced as an intermediary element between the autoclave environment and the bladder interior. This mediator allows pressure equalization while maintaining the integrity of both the bladder and vacuum bag, avoiding direct penetration and associated problems.
2Ease of operation
If multiple penetrations are made in the vacuum bag for venting purposes, then each bladder can be vented individually, but this increases the complexity of the vacuum bag and the risk of leakage
Solution Approach 1:
Multiple vent tubes are bundled together and passed through a single penetration in the vacuum bag. This consolidates multiple venting functions into one location, reducing the number of penetrations required and simplifying the vacuum bag structure while maintaining individual venting capability for each bladder.
Solution Approach 2:
The manifold system is designed to serve multiple bladders through a single vent tube penetration, making the system multi-functional. The same vent tube infrastructure can accommodate different numbers and configurations of bladders, reducing overall system complexity.
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 ensures even pressure distribution to bladders, minimizing leakage, distortion, and resin starvation, while allowing for easy reconfiguration for various part assemblies.
Implementation Method 1
the bladders may be vented to the autoclave environment so that the internal pressure in the bladders is substantially that applied by the autoclave
Implementation Method 2
a vacuum bag and autoclave pressure
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A composite skin (30) and composite stiffeners (32) are co-cured in an autoclave (44). Uncured stiffeners are placed in channels of a tool (46), and an uncured skin is placed on the tool contacting the stiffeners. The vacuum bag (48) is sealed over the tool. Bladders (52) placed in the stiffeners are exposed to autoclave pressure through a manifold system (54) employing vent tubes (56) that pass through the vacuum bag along a side of the tool.