Aircraft Door Frame Toothing Load Transfer
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Solution Overview
Problem
Aircraft door systems face challenges in efficiently transmitting loads in both circumferential and longitudinal directions due to pressure differences at high altitudes, requiring innovative solutions to reduce structural weight and enhance load transmission without compromising mechanical integrity.
Innovation Solution
The door system incorporates a door frame with circumferential struts and frame stoppers featuring complementary toothing, allowing for direct load transfer between the door and frame, along with internal stiffening structures and arcuate stiffening beams to distribute and transmit loads effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If robust stiffening structures are used in the door frame to distribute loads, then structural strength is improved, but device complexity and weight increase
Solution Approach 1:
The door frame is segmented into circumferential struts and longitudinal struts that work together to distribute loads. The stop elements are segmented with multiple toothing patterns that engage with corresponding toothing on the door, creating distributed load paths rather than concentrated stress points.
Solution Approach 2:
The door system employs composite structural elements where the door frame and door are connected through engaging toothing patterns that create a composite load-bearing system. This allows the door itself to contribute to load distribution, reducing the need for additional stiffening structures.
2Ease of manufacture
If the door is suspended by stops allowing radial force transfer only, then ease of manufacture is improved, but strength is worsened due to inability to transfer longitudinal and circumferential loads
Solution Approach 1:
The stop elements are designed with toothing patterns that allow the connection between door and frame to adapt to different loading conditions. The engaging toothing enables the stops to transmit not only radial forces but also longitudinal and circumferential loads, transforming a static radial-only connection into a multi-directional load-bearing connection.
Solution Approach 2:
The stop elements combine multiple functions: they provide the radial suspension function while simultaneously enabling longitudinal and circumferential load transmission through the engaging toothing patterns. This merges previously separate load transmission paths into a unified connection system.
Data Source
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Figure 3
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AI summary
A door system for an aircraft comprises a door frame defining a door opening, with a first circumferential strut and a second circumferential strut spaced apart from the first circumferential strut, at least one first frame stop attached to the first circumferential strut, and at least one second frame stop attached to the second circumferential strut. Each frame stop has a first contact section projecting into the door opening, featuring a first toothed section. The first toothed sections are formed on an inner surface of each of the first contact sections. The door system further comprises a door movably mounted relative to the door frame, which is positioned in the door opening in a closed position, and a number of door stops corresponding to the number of frame stops, arranged on opposite sides of the door and connected to the door, each of which has a second contact section.The second section of the system comprises a second toothed section designed to complement the first. The first toothed section of each frame stop and the second toothed section of each door stop engage with each other when the door is closed.