Aircraft Passenger Door Frame Module Monolithic Design
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Solution Overview
Problem
The existing aircraft passenger door frame assembly process is time-consuming and complex, with a high number of parts leading to increased mass and cost, and suboptimal force distribution and thermal fatigue issues due to complex connections and additional reinforcements.
Innovation Solution
A one-piece main body with a curved design forming a box shape to integrate corner, side, and upper parts, reducing the number of components and eliminating complex connections, allowing for efficient force distribution and reduced mass through optimized thickness and internal reinforcing members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple separate parts are used to assemble the door frame, then the structure can be manufactured with standard processes, but the assembly time increases significantly and manufacturing complexity increases
Solution Approach 1:
The patent combines multiple separate frame parts (lintel, sill, vertical stiffeners, intercostal ribs) into a single integrated door frame structure. This merging eliminates the need for sequential assembly of numerous components, directly resolving the contradiction by maintaining manufacturability through monolithic construction while dramatically improving assembly rate by reducing the number of assembly operations to essentially one installation event.
2Adaptability or versatility
If numerous separate components are assembled to form the door frame, then structural flexibility is improved, but the total mass and manufacturing cost increase
Solution Approach 1:
By integrating all structural elements into a single monolithic door frame, the patent eliminates the cumulative mass of multiple separate components plus their connection hardware. The unified structure maintains structural flexibility through its integrated design while reducing total mass by removing redundant materials and connection elements.
3Strength
If complex connections and additional reinforcements are used at door corners, then force absorption capability is improved, but thermal fatigue problems increase and material costs rise
Solution Approach 1:
The integrated monolithic structure eliminates complex connections and reinforcement joints at door corners by making the corner regions continuous parts of the unified frame. This merging removes the interfaces where thermal expansion/contraction would cause differential stress and fatigue, thereby improving thermal fatigue resistance while maintaining force absorption capability through the continuous structure.
Solution Approach 2:
The patent extracts and eliminates the problematic elements (complex connections, additional reinforcements, multiple interfaces) from the door corner regions. By removing these extraneous components that create thermal fatigue vulnerabilities, the design achieves improved reliability without sacrificing structural strength.
4Strength
If precise connections are made between longitudinal stiffeners and skin with complex curvature, then structural integrity is improved, but assembly time and manufacturing complexity increase
Solution Approach 1:
By consolidating all connection points and structural elements into a single integrated door frame unit, the patent reduces the number of precise connections required from multiple separate joints to essentially one installation interface. This merging maintains structural integrity through the monolithic construction while dramatically reducing connection complexity and associated assembly time.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A frame module (M1) for a passenger door frame (5) configured to be connected to a skin (2) of an aircraft fuselage (1) (A), the frame module (M1) comprising a one-piece main body (6) having at least one corner portion (6d, 6e) curved at an angle between 70° and 110° so as to ensure the transition of forces between an upper and a lateral part of the frame (5), the one-piece main body (6) having an open section defining an inner wall (P1), an outer wall (P2) and a connecting wall (P3) connecting the inner wall (P1) to the outer wall (P2), the inner wall (P1) having an inner tab (61) and the outer wall (P2) having an outer tab (62) configured to be fixed to the skin (2) so as to form a box with an inner cavity.