Composite Aircraft Fuselage Frame Fiber Orientation
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Solution Overview
Problem
Existing structural frames for aircraft fuselages face challenges in achieving high mechanical performance, particularly in circumferential rigidity and buckling resistance, while maintaining simplicity of construction and avoiding complex fiber arrangements.
Innovation Solution
A structural frame with unidirectional fibers oriented at angles between 25 degrees and 35 degrees, and between -35 degrees and -25 degrees relative to the circumferential axis, distributed symmetrically over the thickness, along with additional fibers at 90 degrees, to enhance circumferential rigidity and maintain critical buckling flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If unidirectional fibers are arranged in the circumferential direction to obtain high rigidity, then circumferential rigidity is improved, but critical buckling flux decreases and manufacturing difficulty increases
Solution Approach 1:
The patent changes the fiber orientation angle parameter from the conventional +45/-45 degrees to a new range of +25 to +35 degrees and -35 to -25 degrees. This parameter optimization simultaneously improves circumferential rigidity while maintaining adequate buckling resistance, resolving the contradiction between these two mechanical properties.
Solution Approach 2:
The patent uses composite material structure with unidirectional fibers arranged at optimized angles in the main part, combined with secondary parts (heels) that provide additional structural support. This composite arrangement allows the frame to achieve both high circumferential rigidity and sufficient buckling resistance through the synergistic effect of different fiber orientations and structural components.
2Ease of manufacture
If unidirectional fibers are arranged at +45/-45 degrees to avoid folding issues, then manufacturing ease is improved, but circumferential rigidity is not optimal
Solution Approach 1:
The patent optimizes the fiber orientation angles from the conventional +45/-45 degrees to a narrower range of +25 to +35 degrees and -35 to -25 degrees. This parameter change maintains manufacturing feasibility by avoiding 0-degree arrangements while achieving superior circumferential rigidity through the optimized angle range.
3Device complexity
If fiber arrangement is simplified to reduce production complexity, then ease of manufacture is improved, but mechanical performance may be compromised
Solution Approach 1:
The patent simplifies the fiber arrangement by using a consistent angle range (+25 to +35 degrees and -35 to -25 degrees) throughout the main part, avoiding the need for multiple different orientation patterns. This parameter standardization reduces manufacturing complexity while the optimized angle values ensure high mechanical performance, particularly circumferential rigidity.
Solution Approach 2:
The patent employs a composite structure where the main part uses unidirectional fibers at optimized angles, and secondary parts (heels) provide additional reinforcement. This composite approach maintains high mechanical performance while simplifying the overall manufacturing process compared to more complex multi-directional fiber arrangements.
Data Source
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AI summary
The invention relates to a structural frame (13) made of a composite material. The purpose of the invention is to obtain a structural frame having high mechanical performance while preserving the simplicity of production. The purpose is achieved by providing assemblies of unidirectional fibres (34) in the main portion (31) of the structural frame at a predetermined angle. The device can be used as a structural frame particularly for an aircraft fuselage.