Composite duct with reinforcement
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Solution Overview
Problem
Composite ducts in aircraft Environmental Control Systems face buckling and undesirable physical changes under negative pressure, which existing reinforcement methods fail to adequately address, particularly in terms of weight reduction and cost-effectiveness.
Innovation Solution
The method involves forming a composite duct with reinforcement using a circular cross-section inner ply, an outer ply, and a plurality of cellular core rings positioned at set intervals, which provides additional strength without significantly increasing weight or cost by using honeycomb material and beveled strips to prevent stress risers and ensure airtight seals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional reinforcement methods are used to prevent buckling under negative pressure, then structural integrity is improved, but weight and cost increase
Solution Approach 1:
The patent employs a honeycomb core material with cellular structure that provides high strength-to-weight ratio. The porous honeycomb structure resists buckling under negative pressure while adding minimal weight compared to solid reinforcement materials. The cellular geometry distributes stress effectively across the duct surface.
Solution Approach 2:
The patent creates a composite structure by bonding the honeycomb core between inner and outer composite plies. This multi-material construction combines the flexibility and airtightness of composite materials with the rigid reinforcement of the honeycomb structure, achieving both structural integrity and weight reduction.
2Strength
If traditional reinforcement methods are used to prevent buckling under negative pressure, then structural integrity is improved, but manufacturing cost increases
Solution Approach 1:
The honeycomb core material is available as a standardized, mass-produced component with consistent cellular geometry. This standardization reduces material costs and simplifies procurement, making the reinforcement solution more cost-effective than custom-designed solid reinforcement structures.
Solution Approach 2:
The composite construction method allows for efficient manufacturing through layer-by-layer assembly. The honeycomb core is sandwiched between plies and bonded using standard composite manufacturing techniques, enabling integration into existing production workflows without requiring expensive custom tooling or complex assembly processes.
3Strength
If reinforcement is added to composite ducts, then resistance to buckling is improved, but device complexity increases
Solution Approach 1:
The honeycomb core provides uniform reinforcement across the duct surface through its repeating cellular pattern. This regular geometry simplifies design calculations and stress analysis compared to irregular reinforcement patterns, reducing engineering complexity while maintaining structural performance.
Solution Approach 2:
The sandwich composite structure follows a simple three-layer configuration (inner ply-honeycomb core-outer ply) that is easy to visualize, design, and manufacture. This straightforward architecture reduces design complexity compared to more complex reinforcement schemes while effectively preventing buckling.
Data Source
AI summary
A composite duct with reinforcement comprises an inner ply, an outer ply, and a plurality of cellular core rings. The inner ply forms a channel with a circular cross-section. The plurality of cellular core rings is positioned at set intervals along a length of the composite duct and between the inner ply and the outer ply.