Aircraft Fuselage Lintel Structure for Window Zone Uncoupling

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Solution Overview

Problem

Aircraft fuselage structures face structural irregularities and reinforcement challenges due to window and exit openings, which weaken the structure and complicate assembly, while eliminating windows is not feasible due to psychological and safety concerns.

Innovation Solution

The implementation of a fuselage structure with separate upper and bottom sub-structures connected by lintels, allowing for optimized window zones and uncoupling the constraint between frame spacing and window spacing, enabling independent optimization of window and fuselage zones, and simplifying assembly and production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If window openings are provided in the fuselage to allow passengers to see outside and provide emergency exits, then passenger comfort and safety are improved, but the structural integrity is weakened due to fatigue from pressurization cycles

Engineering Contradiction:

Improvepassenger comfort and safetyVSAvoidstructural integrity

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The fuselage is divided into modular sections with standardized lintel structures that can be independently designed and manufactured. Each lintel acts as a self-contained reinforcement element that can be produced separately and assembled into the fuselage, allowing the window openings to be structurally managed in discrete units rather than as a continuous weak point.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Lintel structures serve as intermediary elements between the window openings and the fuselage skin. These lintels act as mediators that transfer and distribute the structural loads around the openings, preventing stress concentration at the window edges while maintaining the overall fuselage integrity during pressurization cycles.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If reinforcements are added around window openings to compensate for structural weakness, then structural integrity is improved, but the device complexity and assembly difficulty increase

Engineering Contradiction:

Improvestructural integrityVSAvoidassembly complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The lintel structure combines multiple functions into a single integrated component: it provides structural reinforcement, serves as a mounting frame for windows, and acts as a load-transfer element. By merging these functions into one piece, the number of separate reinforcement components and assembly steps is reduced, simplifying both the device complexity and assembly process.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The lintel is designed as a universal component that can be used across different fuselage sections and window configurations. The standardized lintel design allows it to perform multiple roles simultaneously - structural reinforcement, window support, and stress distribution - making it applicable throughout the fuselage without requiring custom-designed reinforcements for each window.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Strength

If frames are arranged in the axis of windows with Y-shaped divisions to ensure continuous force flow, then structural integrity around windows is improved, but the frame complexity and production difficulty increase

Engineering Contradiction:

Improveforce flow continuityVSAvoidframe production ease

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

Instead of making the frames complex with Y-shaped divisions to accommodate windows, the approach is inverted: simple straight frames are used, and the lintel structure is designed to accommodate the frames while providing the necessary force flow continuity around the windows. This reverses the complexity from the frame to the lintel, which is a separate, easily manufactured component.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The force-flow management function is extracted from the frame structure and placed into the lintel structure. By taking out the complexity of force redistribution from the frames and concentrating it in the lintels, the frames themselves can remain simple, straight, and easy to manufacture, while the lintels handle the sophisticated stress management around the window openings.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS11312469B2Lintel structure for aircraft fuselage and fuselage comprising such a lintel

Publication Date: 2022.04.26 AIRBUS ATLANTIC (SAS)

AI summary

An aircraft fuselage includes a structure, considered in respect of all or part of the fuselage, with fuselage upper sub-structure constituting an upper part of the fuselage and a fuselage bottom sub-structure constituting a lower part of the fuselage. Openings in the structure of the fuselage are intended for the installation of windows or doors for exiting the fuselage. Furthermore, the fuselage upper sub-structure and the fuselage bottom sub-structure form fuselage sub-structures that are assembled with one another via at least one lintel in which all or some of the openings intended for installing the exit doors or windows are formed.