Composite Stiffener Panel Flexible Bladder Molding
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Solution Overview
Problem
Existing methods for manufacturing stiffened composite panels face issues such as excessive play between stiffeners and cores leading to pressure gradients, surface defects, and the difficulty in extracting and reusing cores, which result in inefficiencies and increased scrap during polymerization.
Innovation Solution
A process involving a rigid counter-mold for each stiffener, a flexible and sealed bladder for compacting, and a sealable chamber to manage pressure and prevent defects, allowing for easier core extraction and reusability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rigid molding device with grooves is used to manufacture the stiffened panel, then the stiffeners can be properly shaped and positioned, but excessive play between the stiffener caps and the molding device causes pressure gradients during polymerization
Solution Approach 1:
The patent replaces the rigid molding device with a flexible bladder that can conform to the stiffener geometry. The flexible bladder eliminates play between the stiffener caps and molding surface, ensuring homogeneous pressure distribution during polymerization while maintaining proper stiffener positioning through its conformability to the stiffener shape.
Solution Approach 2:
The patent changes the physical state of the molding element from rigid to flexible. By using a flexible bladder that can deform and adapt to the stiffener profile, the system eliminates the play issue while maintaining manufacturing precision. The flexible bladder can be pressurized to provide uniform contact pressure across the stiffener caps.
2Shape
If rigid cores are used to maintain stiffener shape during polymerization, then the stiffeners retain their geometry, but the cores are difficult to extract and require dissolution
Solution Approach 1:
The patent replaces rigid cores with flexible bladders that can be easily deflated and removed. The flexible bladder maintains stiffener geometry during polymerization through its conformability and can be easily extracted by deflation without requiring dissolution, significantly simplifying the manufacturing process.
Solution Approach 2:
The patent transitions from static rigid cores to dynamic flexible bladders that can adapt their state. The flexible bladder can be inflated to maintain stiffener shape during polymerization, then deflated for easy removal. This dynamic approach allows the same element to serve both structural and removable functions.
3Shape
If a rigid molding device is used, then the panel surface can be properly formed, but surface defects occur due to pressure gradients perpendicular to the play between stiffener caps and device
Solution Approach 1:
The flexible bladder conforms to the stiffener profile and eliminates gaps between the stiffener caps and molding surface. This ensures homogeneous pressure distribution during polymerization, preventing the pressure gradients that cause surface defects like fiber deviations while maintaining proper panel surface formation.
4Manufacturing precision
If rigid cores with dimensions calibrated to stiffener recesses are used, then the stiffeners are properly supported, but multiple cores are needed for different stiffener shapes
Solution Approach 1:
The flexible bladder serves as a universal support element that can adapt to different stiffener shapes through its flexibility. A single type of flexible bladder can be used for various stiffener geometries, eliminating the need for multiple specialized rigid cores and simplifying inventory and manufacturing.
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 process simplifies core extraction, reduces surface defects by ensuring homogeneous pressure, and allows for the reuse of components, thereby improving manufacturing efficiency and reducing waste.
Implementation Method 1
subjecting the interior of said bladder to pressure during polymerization for compacting the stiffener and the panel
Implementation Method 2
polymerizing the unit by subjecting it to pressure
Data Source
AI summary
A process for the production of a stiffened panel made of composite material, includes the stages of depositing the fibers that constitute the panel on a rigid device (50), depositing the at least one stiffener (14), covering the unit with a sealed wall connected to the rigid device (50) on the periphery of the panel, and then polymerizing, and providing—for each stiffener (14)—a rigid counter-mold in contact with the convex surface of the stiffener (14), using—for each stiffener (14)—a core (66) in the form of a flexible and sealed bladder, and subjecting the interior of the bladder to pressure during polymerization for compacting the stiffener (14) and the panel.