Aircraft Fuselage Skin Expansion for Tolerance Compensation

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Solution Overview

Problem

Current methods for manufacturing aircraft fuselage sections, whether through monocoque construction or composite materials, lack tolerance compensation, leading to challenges in assembling rigid sections with varying dimensions due to manufacturing tolerances.

Innovation Solution

A method involving the manufacture of an outer skin segment with a continuous longitudinal opening, allowing for tolerance compensation by spreading or compressing the segment to form a seamless connection with a prefabricated rigid fuselage section, using materials like aluminum alloy or fiber-reinforced plastics, and joining through processes like friction stir welding or riveting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If rigid fuselage sections are manufactured by monocoque construction or composite materials, then manufacturing precision and structural integrity are improved, but tolerance compensation capability deteriorates

Engineering Contradiction:
Improvestructural integrityVSAvoidtolerance compensation
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The fuselage section is divided into multiple shell segments that are joined together by longitudinal seams. This segmentation allows the structure to be both rigid (through welding) and adaptable (through controlled flexibility in the seam areas) to compensate for manufacturing tolerances during assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the physical state of the fuselage section by introducing controlled flexibility through incomplete riveting of longitudinal seams. This parameter change allows the rigid structure to adapt to tolerance variations while maintaining overall structural integrity.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If fuselage sections are manufactured with complete longitudinal seam riveting, then structural rigidity is improved, but assembly adaptability deteriorates

Engineering Contradiction:
Improvestructural rigidityVSAvoidtolerance compensation
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

Different parts of the fuselage section have different qualities: areas with completely riveted longitudinal seams provide rigidity, while areas with incompletely riveted seams provide flexibility for tolerance compensation. This local differentiation allows both rigidity and adaptability to coexist in the same structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The fuselage section transitions from a completely static rigid structure to a dynamic structure where certain longitudinal seam areas can flex to accommodate tolerance variations during assembly, while other areas maintain rigidity for structural stability.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If conventional shell construction with riveting is used, then tolerance compensation is improved, but manufacturing precision and seam quality deteriorate

Engineering Contradiction:
Improvetolerance compensationVSAvoidseam quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent replaces traditional mechanical riveting with friction stir welding for longitudinal seams, achieving superior seam quality and structural integrity while maintaining the tolerance compensation capability through controlled flexibility in specific riveted areas.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The fuselage section combines different joining methods (friction stir welding for high-quality seams and selective riveting for flexibility) to create a composite construction that achieves both high manufacturing precision and tolerance compensation capability.

Inventive Principle:
Principle #40Composite materials

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

Enables seamless and rigid connections between fuselage sections, accommodating manufacturing tolerances and ensuring high-quality longitudinal seams, thereby improving the assembly efficiency and mechanical properties of aircraft fuselage cells.

Implementation Method 1

The aluminum shell segments are preferably welded together using the friction stir welding process in order to achieve a high longitudinal seam quality whose mechanical properties are comparable to those of the solid material.

Methodology Applied
Scientific EffectFriction stir welding: Friction Welding

Data Source

PatentEP2200897B1Method for the production of a fuselage airframe of an aircraft
Publication Date: 2015.11.11 AIRBUS OPERATIONS GMBH
  • EP2200897B1 patent drawingFigure 1~2
  • EP2200897B1 patent drawingFigure 3~4
  • EP2200897B1 patent drawingFigure 5~6

AI summary

Disclosed is a method for producing a fuselage airframe of an aircraft. Said method, in which several fuselage sections that are arranged one behind another are joined together, comprises the following steps: a) an external skin segment (1, 4, 9, 14, 20) is produced which encompasses a continuous longitudinal opening (3, 11, 22) on the bottom; b) the external skin segment (1, 4, 9, 14, 20) is expanded in order to introduce additional components; c) the external skin segment (1, 4, 9, 14, 20) is joined to an existing rigid fuselage section (23) such that a partial transverse seam (33) is formed; d) a prefabricated bottom shell (5, 17, 21) is placed in the longitudinal opening (3, 11, 22) to close the external skin segment (1, 4, 9, 14, 20); e) the partial transverse seam (33) is completed to form a transverse seam, and the bottom shell (5, 17, 21) and the external skin segment (1, 4, 9, 14, 20) are joined together such that at least two longitudinal seams (46, 47) are formed; and f) the floor frame (34) and the external skin segment (1, 4, 9, 14, 20) are joined together.