Curved Composite Fuselage Frame with Local Widening
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Solution Overview
Problem
Existing methods for manufacturing curved structural parts with composite reinforced-fiber materials face challenges in spreading fibers oriented perpendicular to the local radius of curvature, leading to pucker formation and difficulties in accommodating the necessary number of fasteners for mechanical load transfer in aircraft fuselage structures, which increases weight and reduces interior volume.
Innovation Solution
A curved structural part with a varying section width parallel to the local radius of curvature, featuring continuous fibers oriented between 30° and 60°, and local widening at connections, allowing for adequate fastener spacing without complex spliced parts, and a manufacturing process involving gradual application and tensioning of multidirectional fiber strips to prevent puckering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fibers are oriented perpendicular to the local radius of curvature (0° direction) in curved structural parts, then the structural strength is improved, but pucker formation occurs during spreading which damages the mechanical hold of the part
Solution Approach 1:
The patent changes the fiber orientation parameter from perpendicular (0°) to an angled orientation (30°-60°) relative to the local radius of curvature. This parameter modification eliminates pucker formation during spreading while maintaining structural strength, as the angled orientation allows fibers to follow the curved geometry without creating compressive stresses that cause puckers.
Solution Approach 2:
Instead of orienting fibers perpendicular to the radius of curvature as traditionally done, the patent inverts this approach by orienting them at an angle (30°-60°) to the radius of curvature. This inverted orientation strategy resolves the contradiction by preventing pucker formation while still providing adequate structural reinforcement.
2Strength
If the section width is increased to accommodate more fasteners for mechanical load transfer, then the connection strength is improved, but the interior volume of the aircraft fuselage is reduced
Solution Approach 1:
The patent applies local quality by creating local widening of the section width specifically at connection zones where fasteners are required, while maintaining the original narrow width in non-critical areas. This allows adequate fastener spacing and connection strength only where mechanically necessary, preserving interior volume in the overall structure.
Solution Approach 2:
The structural part is segmented into different zones: connection zones with increased width for fastener accommodation, and non-critical zones with reduced width for volume optimization. This segmentation allows the structure to have adequate connection strength without sacrificing overall interior volume.
3Strength
If complex spliced parts are used to accommodate fasteners, then the connection strength is improved, but the device complexity and weight increase
Solution Approach 1:
The patent extracts the fastener accommodation function from complex spliced parts and integrates it directly into the main structural element through local widening. This eliminates the need for separate complex spliced components, reducing overall device complexity and weight while maintaining connection strength.
Solution Approach 2:
The structural element is designed to serve multiple functions: it provides structural reinforcement, accommodates fasteners through local widening, and maintains structural continuity. This multi-functionality eliminates the need for separate specialized spliced parts, reducing complexity.
Data Source
AI summary
The disclosed embodiments concern a curved structural part composed of a composite material with reinforced, continuous fibers whose cross section includes at least two wings, with said fibers extending from one wing to the other, with said structural part having a variation in the width of its section parallel to the local radius of curvature. The structural element that results from assembling the parts in the disclosed embodiments therefore has local widening of the section at the connections between the parts constituting a structural element, such as an aircraft fuselage frame, and widening at the connection with the floor profiles, if such a profile is used to make an aircraft fuselage structure. The disclosed embodiments also concern a process for manufacturing such a part, as well as a device for advantageously implementing such a process.