Composite Bracket With Folded Stiffener for Lightweight Vibration Resistance
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Solution Overview
Problem
Metal fittings used in aerospace applications for fastening cabling and pipework are heavy due to their metal composition, leading to increased weight and vibration fatigue, and existing composite material solutions are costly to produce.
Innovation Solution
A composite material bracket with a slot and a folded stiffener, where the stiffener is fastened to the bracket using tabs, allowing for simplified production and reduced weight by using thermoplastic matrix composite materials or alternative materials with thermoplastic anchoring, and tooling for simultaneous folding and fastening of the bracket and stiffener.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal fittings are used, then strength and reliability are improved, but weight increases
Solution Approach 1:
The bracket is made from composite material (fiberglass reinforced plastic) instead of metal, providing sufficient strength and stiffness while significantly reducing weight. The composite material allows for weight reduction while maintaining the structural integrity required for aerospace applications.
Solution Approach 2:
The fitting is divided into distinct functional components: the bracket made from composite material and the stiffener made from metal or composite material. This segmentation allows each component to be optimized for its specific function while contributing to overall weight reduction.
2Reliability
If stiffeners are added to offset resonant frequencies, then vibration resistance is improved, but device complexity increases
Solution Approach 1:
The stiffener is integrated with the bracket through a slot and tab connection system, combining the stiffening function with the bracket structure. The tabs extend from the stiffener through the slot in the bracket, creating a unified assembly that reduces complexity compared to separate mounting operations.
Solution Approach 2:
The slot is pre-formed in the bracket at the appropriate location and orientation before the stiffener is installed. This preliminary preparation of the mounting path simplifies the assembly process and reduces the complexity of the fastening operation.
3Weight of moving object
If composite material is used, then weight is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The slot is pre-formed in the composite bracket with precise dimensions and orientation before stiffener installation. This preliminary preparation ensures accurate alignment and positioning, reducing the precision requirements during the final assembly operation.
Solution Approach 2:
The tab-and-slot connection system provides self-aligning and self-centering characteristics during assembly. The geometry of the slot and tabs guides the stiffener into the correct position, reducing the need for high-precision manual alignment and simplifying the manufacturing process.
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
The solution reduces the weight of fittings while simplifying production, providing effective fastening and resistance to vibration fatigue, and enabling the use of composite materials that are cost-effective and suitable for aerospace applications.
Implementation Method 1
the bracket may be produced by being folded at high temperature so as to melt the thermoplastic matrix at least in part in order to facilitate folding
Implementation Method 2
folding a first flat part along a straight line in order to form a bracket having two flat segments joined together by the edge and forming an angle less than 180°
Data Source
AI summary
A fitting including at least one composite material bracket with two flat segments forming an angle less than 180° on an inside of the bracket and an angle greater than 180° on an outside of the bracket, together with a stiffener extending on the inside of the bracket between the two flat segments is disclosed. The bracket presents a slot crossing a straight line between the two flat segments, the slot extending into the two flat segments. The stiffener is folded in register with the slot and includes tabs fastened to each of the two flat segments.