Composite Fuselage Skeleton Co-Curing Tooling
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Solution Overview
Problem
The existing methods for fabricating aircraft fuselages with composite materials are labor-intensive and require extensive positional tooling, leading to inefficiencies and increased costs due to the need for individual tooling and caul sheets for bonding stringers and frames to the skin.
Innovation Solution
A method involving the partial curing of frames and stringers with locking features, which are then assembled on a solitary skeleton tool, allowing for a support system to be formed and fully cured with the skin, eliminating the need for extensive tooling and caul sheets, and utilizing the prepreg skin as an adhesive for secure bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If individual tooling and caul sheets are used for bonding each stringer and frame to the skin, then structural integrity is achieved, but labor time and manufacturing complexity increase significantly
Solution Approach 1:
The patent combines multiple separate bonding operations into a single integrated co-curing process. All stringers and frames are bonded to the skin simultaneously in one autoclave cycle, eliminating the need for individual tooling and multiple bonding steps. This merging of operations maintains structural integrity while dramatically improving productivity.
Solution Approach 2:
The patent employs universal support blocks and positioning fixtures that can accommodate multiple different stringer and frame configurations. These reusable tools serve multiple functions across different bonding operations, eliminating the need for custom individual tooling for each component while ensuring proper structural alignment and bonding quality.
2Productivity
If extensive positional tooling is used to co-cure components simultaneously, then manufacturing time is reduced, but device complexity and initial costs increase
Solution Approach 1:
The patent segments the tooling system into simple, modular components: support blocks positioned at specific locations, basic positioning fixtures, and standard clamping mechanisms. This segmentation avoids the need for complex integrated tooling while enabling simultaneous co-curing of multiple components through a straightforward setup process.
Solution Approach 2:
The patent uses replicated support blocks and positioning elements that can be reused across multiple bonding operations. Instead of designing complex custom tooling for each configuration, standardizable copying elements are employed that maintain precision while reducing overall system complexity and initial investment costs.
3Productivity
If bond mandrels are used for co-curing, then some components can be bonded simultaneously, but mandrel removal and additional bonding steps are required
Solution Approach 1:
The patent extracts and eliminates the mandrel element from the bonding process entirely. Instead of using removable bond mandrels that require subsequent removal and additional bonding steps, the system employs direct support blocks and positioning fixtures that remain in place throughout the process, simplifying the manufacturing sequence while maintaining bonding efficiency.
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 reduces labor and material costs, achieves tighter tolerances, and simplifies the fabrication process by eliminating the need for individual component bonding, resulting in a more efficient and cost-effective method for constructing composite fuselage sections.
Implementation Method 1
forming a first frame, a second frame, and a third frame by partially curing a composite material
Implementation Method 2
A support system is formed by securing using adhesive the first, the second, and the third frames to each of the first, second, and the third stringers
Implementation Method 3
The skin and the support system are then fully cured to form the fuselage section
Data Source
AI summary
A method for making a fuselage section comprises the steps of assembling a support system. The support system comprises fiber reinforced composite material and includes at least three frames and six stringers. The support system is partially cured such that the support system attains about eighty percent of its fully cured strength. A skin comprising fiber reinforced composite material is globally positioned such that an inner surface of the skin corresponds to an outer surface of the support system. The skin and the support system are fully cured together. The support system is assembled on a skeleton assembly tool having a bonding surface corresponding to an inner surface of the skin.