Deformable Peripheral Frame for Aircraft Pressure Bulkhead
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Solution Overview
Problem
Existing pressure bulkhead systems in vehicles, particularly aircraft, face challenges in managing differential pressures between pressurized and unpressurized cabin spaces, leading to high stresses on peripheral frames and potential separation issues due to rigid designs.
Innovation Solution
A pressure bulkhead system with a deformable peripheral pressure frame that connects the pressure bulkhead to the fuselage, featuring a flexible section with curved junctions to accommodate cabin pressure, reducing stress and providing a secure, lightweight connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid peripheral pressure frame is used to connect the pressure bulkhead to the fuselage, then the connection strength is improved, but the stress concentration and risk of separation increase under cabin pressure loads
Solution Approach 1:
The peripheral pressure frame transitions from a rigid structure to a dynamic, deformable structure. The frame is designed with flexible sections that allow controlled deformation under cabin pressure loads, enabling the structure to adapt to pressure changes while maintaining connection integrity and reducing stress concentration at rigid joints.
Solution Approach 2:
The stiffness parameter of the peripheral pressure frame is varied along its length. Certain sections are designed with reduced stiffness to allow deformation, while other sections maintain higher stiffness for structural support. This gradient in stiffness parameters enables the frame to distribute stresses more evenly and prevent localized stress concentration that could lead to separation.
2Weight of stationary object
If a dome-shaped pressure bulkhead is used, then the skin thickness can be reduced, but the cabin space is compromised
Solution Approach 1:
The invention introduces curved junctions at critical points where the peripheral pressure frame connects to the pressure bulkhead and fuselage. These curved transitions distribute stress more effectively than sharp angles, allowing for thinner skin sections while maintaining structural integrity. The curvature enables the frame to deform smoothly under pressure without creating stress concentration points.
3Volume of stationary object
If a flat pressure bulkhead is used, then the cabin space is improved, but the stress distribution on the peripheral frame worsens
Solution Approach 1:
The peripheral pressure frame is segmented into distinct functional sections: rigid sections for structural support and flexible sections for stress accommodation. The flexible sections are strategically positioned at the junctions between the pressure bulkhead and fuselage, where stress concentration is most likely to occur. This segmentation allows the frame to handle both the spatial requirements of a flat bulkhead and the stress management needs of pressure differential.
Solution Approach 2:
The flexible sections of the peripheral pressure frame act as intermediary elements between the rigid structural components. These sections absorb and redistribute stresses that would otherwise concentrate at the junction points, mediating the interaction between the flat pressure bulkhead and the fuselage structure while preventing stress-related failures.
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 flexible design of the peripheral pressure frame effectively reduces stress and ensures a reliable, lightweight connection between the pressure bulkhead and the fuselage, preventing separation and accommodating thermal expansion differences.
Implementation Method 1
the peripheral pressure frame is capable of deforming, to a certain extent, in response to a cabin pressure load acting on the pressure bulkhead and to thus reduce the stresses acting on the peripheral pressure frame
Implementation Method 2
accommodating thermal expansion differences
Data Source
AI summary
A pressure bulkhead system comprises a pressure bulkhead adapted to be connected to a fuselage of a vehicle to separate a pressurized cabin space of the vehicle from an unpressurized cabin space of the vehicle, and a peripheral pressure frame to sealingly connect the pressure bulkhead to the vehicle fuselage. The peripheral pressure frame comprises an attachment section sealingly attached to an outer rim portion of a first surface of the pressure bulkhead. The first surface, when the pressure bulkhead system is installed in the vehicle, faces the unpressurized cabin space of the vehicle. A flange section is adapted to be sealingly attached to an inner surface of the vehicle fuselage and extends in a direction facing away from the first surface of the pressure bulkhead. A flexible section interconnects the attachment section and the flange section and is flexible to accommodate cabin pressure acting on the pressure bulkhead.