Composite Longitudinal Beam Joint for Pressure Deck Assembly

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Solution Overview

Problem

Aircraft fuselage pressure deck assemblies face challenges in achieving corrosion resistance and weight reduction while maintaining structural integrity under pressure loads, as corrosion-resistant metals are heavy and composite materials may not adequately withstand inter-laminar tension.

Innovation Solution

The pressure deck assembly incorporates longitudinal beams fabricated from composite materials, featuring a central member with opposing flanges and compliant deck segments that distribute load through joints designed to reduce inter-laminar tension, allowing for the use of lighter materials and enhanced structural performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If corrosion resistant metals are used for longitudinal beams, then corrosion resistance is improved, but weight increases

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidweight of longitudinal beams
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies composite materials (specifically carbon fiber reinforced polymers) to fabricate longitudinal beams instead of traditional corrosion resistant metals. This resolves the contradiction by providing both corrosion resistance and weight reduction, as composites offer protective surfaces while maintaining structural integrity with lower density materials.

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If corrosion resistant composite materials are used for longitudinal beams, then weight is reduced, but inter-laminar tension capability becomes insufficient

Engineering Contradiction:
Improveweight of longitudinal beamsVSAvoidinter-laminar tension capability
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent applies local quality by implementing specific structural features at critical locations where inter-laminar tension occurs. This includes designing flange configurations, joint geometries, and layer orientations in the composite beams to locally enhance ILT resistance without increasing overall weight, addressing the weakness of composite materials at specific stress points.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3838741B1Longitudinal beam joint for a pressure deck assembly
Publication Date: 2023.08.23 THE BOEING CO
  • EP3838741B1 patent drawingFigure 1
  • EP3838741B1 patent drawingFigure 2
  • EP3838741B1 patent drawingFigure 3

AI summary

A pressure deck assembly for a fuselage includes a longitudinal beam extending a length along a roll axis of the fuselage. The longitudinal beam includes a central member and opposing first and second flanges extending from the central member. The first flange includes a first upper side and a first lower side. The second flange includes a second upper side and a second lower side. The pressure deck assembly includes a pressure deck that includes first and second deck segments. The first deck segment is joined to the first flange of the longitudinal beam along the first lower side of the first flange. The second deck segment is joined to the second flange of the longitudinal beam along the second lower side of the second flange.