Tapered Rib Insertion in Composite Cavity Structure
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Solution Overview
Problem
Mechanically fastening internal stiffening components in composite aircraft structures is time-consuming and adds weight, while also interfering with molding techniques and tooling used in composite structure formation.
Innovation Solution
A composite structure design featuring a first and second composite skin with a longitudinal cavity, spars connecting them, and a rib inserted between spars, which is tapered to fit within the cavity, providing structural support without the need for mechanical fastening, and a method for forming this structure by curing the skins and spars before inserting the rib.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If mechanically fastening ribs within composite structures, then structural support is provided, but fabrication time increases and weight increases
Solution Approach 1:
The rib is pre-formed with a tapered configuration that enables it to be inserted into the composite structure before final curing. This preliminary preparation allows the rib to be positioned and integrated into the mold cavity before the composite material sets, eliminating the need for post-assembly mechanical fastening operations and significantly reducing fabrication time while maintaining structural support
2Strength
If mechanically fastening ribs within composite structures, then structural support is provided, but the structure weight increases
Solution Approach 1:
The invention replaces mechanical fastening systems (such as bolts, screws, or clips) with a tapered interference fit system. The rib's tapered geometry allows it to be pressed into place within the composite structure, creating a mechanical interlock through friction and geometric constraint rather than through separate fastening components. This substitution eliminates the weight of additional fastening hardware while providing equivalent structural support
3Strength
If using internal stiffening components, then structural support is provided, but molding techniques are interfered with and tooling is obstructed
Solution Approach 1:
The rib is prepared in advance with a tapered configuration that allows it to be inserted into the mold cavity before the composite material is applied and cured. This preliminary positioning ensures that the rib is already in its final location when molding begins, eliminating interference with the molding process and allowing tooling to operate unobstructed. The rib's tapered design also facilitates easy removal from the mold after curing without damaging surrounding structures
Data Source
AI summary
A composite structure includes a first composite skin and a second composite skin spaced from the first composite skin. The first composite skin and the second composite skin define a longitudinal cavity therebetween. The composite structure further includes a plurality of spars located in the longitudinal cavity and laterally spaced from one another. The plurality of spars extends between and connects the first composite skin and the second composite skin. The composite structure further includes at least one rib located within the longitudinal cavity between a first spar and a second spar of the plurality of spars. The first spar is laterally adjacent the second spar. The at least one rib is in contact with the first composite skin, the second composite skin, the first spar and the second spar.