Composite Aircraft Fuselage Fabrication via Internal Framework Molding

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Solution Overview

Problem

Traditional metal fuselage construction in aircraft is heavy and aerodynamically inefficient due to excess thickness and weight, and existing composite material techniques struggle with fabricating hollow bodies with changing shapes and require lengthy assembly processes.

Innovation Solution

The technique involves fabricating an aircraft fuselage with an internal framework that serves as a mold and support for the composite outer skin, allowing for the assembly of the framework before the skin, using shell fixtures to create a solid structure that is then covered with composite material and molded into shape, eliminating the need for post-fabrication internal framework installation and enabling seamless, one-piece construction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal panels are used to fabricate the fuselage, then the fuselage structure is strong and rigid, but the weight increases and aerodynamic drag increases due to excess thickness from joints

Engineering Contradiction:

Improvefuselage structure strengthVSAvoidfuselage weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent applies composite materials (fiber reinforcement + resin) to replace traditional metal panels for fabricating the fuselage outer skin. This allows creating a strong, lightweight structure without the excess thickness problems associated with metal joints, directly resolving the contradiction between strength and weight

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If composite material panels are fabricated using traditional molding techniques, then the outer skin can be created, but the internal framework must be assembled piece by piece which is time-consuming and complex

Engineering Contradiction:

Improveouter skin fabricationVSAvoidinternal framework assembly time

Core Design Contradiction:

Ease of manufactureVSLoss of time

Solution Approach 1:

The patent applies preliminary action by assembling the entire internal framework before fabricating the outer skin. The framework is prepared in advance as a complete structure, allowing the outer skin to be molded in one continuous operation around the entire framework, eliminating time-consuming post-assembly operations

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If the internal framework is assembled piece by piece during outer skin fabrication, then the framework can be adapted to the outer skin shape, but the fabrication process becomes complex and time-consuming

Engineering Contradiction:

Improveframework adaptation to outer skinVSAvoidfabrication process complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies inversion by reversing the traditional sequence: instead of assembling the framework during outer skin fabrication, the framework is assembled first, then the outer skin is fabricated around it. This simplifies the process while maintaining adaptability, as the outer skin conforms to the pre-assembled framework structure

Inventive Principle:

Principle #13The other way round (Inversion)

4Ease of manufacture

If traditional molding techniques are used for composite material fabrication, then panels can be produced, but hollow bodies with changing shapes are difficult to fabricate

Engineering Contradiction:

Improvepanel fabricationVSAvoidcapability to fabricate complex shapes

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent applies dimensionality change by transitioning from 2D panel fabrication to 3D hollow body formation. The internal framework provides a three-dimensional structure that enables the outer skin to be molded into complex hollow shapes with varying cross-sections, overcoming the limitations of traditional 2D molding techniques

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

This method reduces weight and assembly time, allows for complex shapes without seams, and improves aerodynamics by eliminating excess thickness and simplifying the construction process, resulting in a lightweight, aerodynamically enhanced fuselage.

Implementation Method 1

Under the effect of heat, the resin polymerizes, permitting the fiber reinforcement to preserve the shape of the mold

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

The mold thus wrapped with pre-coated fiber sheets is heated on order to polymerize the resin. After cooling, the laminate obtained shapes the outer skin of the aircraft

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS8220154B2Method for fabricating an aircraft fuselage in composite material

Publication Date: 2012.07.17 AIRBUS OPERATIONS (SAS)

AI summary

A method for manufacturing an aircraft fuselage includes an internal framework surrounded by an external skin made of composite material, in which the internal framework at least partially constitutes a mould for manufacture and/or the support for the mould for the external skin made of composite material. The disclosed embodiments also relate to an aircraft fuselage produced using this method.