Composite Aircraft Window Frame Barrier Layer for Surface Homogeneity

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Solution Overview

Problem

Existing aircraft window frames made of composite materials with embedded fibers in a resin matrix exhibit non-homogeneous surfaces due to resin accumulation at high-curvature junctions, leading to visual inconsistencies in paintwork.

Innovation Solution

Incorporating a barrier layer between the reinforcement and the surface to prevent resin spread, and using offset seams to limit resin accumulation, ensuring a more uniform outer surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If reinforcement is positioned at the junction zone with high curvature, then structural strength is improved, but resin accumulation occurs causing surface non-homogeneity

Engineering Contradiction:
Improvestructural strengthVSAvoidsurface homogeneity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The reinforcement is segmented into multiple discrete elements positioned at the junction zone, allowing resin to flow around each segment rather than accumulating against a continuous barrier, thus maintaining strength while improving surface homogeneity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An intermediary layer or surface treatment is introduced between the reinforcement and the outer surface to prevent resin accumulation, allowing the reinforcement to remain at the high-curvature junction zone for structural strength while the intermediary prevents the harmful resin buildup that causes surface non-homogeneity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If seams are positioned at the first surface level, then assembly is simplified, but resin accumulation at seams creates visual inconsistencies

Engineering Contradiction:
Improveassembly simplicityVSAvoidpaintwork consistency
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The seams are extracted from the first surface level and repositioned to the second surface level, removing the source of visual inconsistency (resin accumulation at seams on the visible surface) while maintaining assembly simplicity through the offset positioning strategy

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The seam positioning is moved from a two-dimensional surface level consideration to a three-dimensional spatial arrangement, where seams are offset in the radial direction to the second surface, allowing resin to accumulate away from the visible first surface while maintaining manufacturing ease

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4385881B1Method for manufacturing an aircraft window frame comprising a barrier layer, window frame obtained from said method and aircraft comprising at least one such window frame
Publication Date: 2026.02.25 AIRBUS OPERATIONS (SAS)
  • EP4385881B1 patent drawingFigure 1~3
  • EP4385881B1 patent drawingFigure 4~5
  • EP4385881B1 patent drawingFigure 6~7

AI summary

The invention relates to a method for manufacturing an aircraft window frame (118.1), said frame comprising a first surface (S1) having a curved junction zone (133) extending around the entire perimeter of the frame (118.1), the latter being made of composite material and comprising a stack of fiber layers (132, 134, 134') as well as at least one reinforcement (136) located at the junction zone (133). The manufacturing method includes an assembly step of the different fiber layers (132, 134, 134') and the reinforcement (136) during which a barrier layer (138) is positioned between the reinforcement (136) and the first surface (S1) so as to form a barrier limiting the propagation of resin towards the first surface (S1). The invention also relates to a porthole frame obtained from this process and to an aircraft comprising said frame.