Duct Stringer Bulkhead Assembly for Tolerance-Tolerant Sealing
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Solution Overview
Problem
Existing duct stringer assemblies in aircraft wings face challenges with tolerance buildup during manufacturing and assembly, necessitating complex sealant application and complicating maintenance access, especially with composite components.
Innovation Solution
A duct stringer assembly featuring a bulkhead with a gasket and mechanical fixing, allowing for tolerance accommodation and simplified assembly, with a gasket sealing the gap between the bulkhead body and duct walls, and enabling removable bulkheads for easy maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bulkhead is installed in a duct stringer assembly to block fluid flow, then fluid flow control is improved, but tolerance buildup during manufacturing and assembly increases complexity
Solution Approach 1:
A gasket is introduced as an intermediary element between the bulkhead and the duct stringer assembly. The gasket accommodates tolerance buildup by providing a compliant sealing interface that compensates for dimensional variations, eliminating the need for complex tolerance control while ensuring reliable fluid flow blocking.
Solution Approach 2:
The gasket material properties are selected to change under compression, allowing it to deform and fill gaps caused by tolerance variations. This parameter change enables the sealing interface to adapt to manufacturing tolerances without requiring high precision assembly.
2Reliability
If curable sealant material is used to seal around the bulkhead body, then sealing is achieved, but manufacturing complexity and time increase
Solution Approach 1:
The chemical curing process of sealant material is replaced with a mechanical compression system. The gasket is compressed between the bulkhead and duct stringer using mechanical fasteners, eliminating the need for curable sealant material and associated complexity in application and curing processes.
3Reliability
If a fixed bulkhead design is used to block fluid flow, then fluid flow control is improved, but maintenance access to the duct becomes difficult
Solution Approach 1:
The bulkhead is segmented from the duct stringer assembly through the use of removable mechanical fasteners. This segmentation allows the bulkhead to be detached and removed independently, providing easy maintenance access to the duct interior while maintaining reliable fluid flow blocking when installed.
4Reliability
If a gasket is compressed between the bulkhead body and duct walls to seal the gap, then sealing is achieved and tolerance buildup is accommodated, but additional components are required
Solution Approach 1:
The gasket serves multiple functions simultaneously: it provides sealing against fluid leakage, accommodates tolerance buildup through deformation, and distributes compression forces across the bulkhead and duct interface. This multi-functionality reduces the need for additional specialized components.
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 need for curable sealant material, simplifies assembly, and facilitates easy maintenance by allowing bulkhead removal, thus addressing tolerance issues and enhancing manufacturing efficiency.
Implementation Method 1
The gasket may be compressed between the bulkhead body and the duct walls.
Implementation Method 2
The gasket may include an elastomeric material.
Data Source
AI summary
A duct stringer assembly with a bulkhead. The duct stringer assembly has duct walls providing a duct with a closed cross-section. The duct is adapted to transport fluid. A bulkhead is in the duct, and the bulkhead is adapted to block the flow of fluid along the duct. The bulkhead has a bulkhead body, and a gasket sealing a gap between the bulkhead body and the duct walls.