Aircraft Window Frame Bonding for Composite Fuselage Skins
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Solution Overview
Problem
The existing methods for joining a window frame to an aircraft fuselage, typically using rivet joints, are time-consuming and labor-intensive, with a punctual connection that limits the load transfer and deformation behavior between the window frame and the fuselage skin.
Innovation Solution
A method involving a curable connecting layer around the window opening, where the window frame is pressed onto the layer and subjected to a curing process with the fuselage skin, creating a continuous, integral connection that eliminates the need for rivets and simplifies the structure and fiber alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rivet joints are used to connect the window frame to the fuselage skin, then the connection is simple to implement, but the connection is time-consuming and labor-intensive with limited load transfer
Solution Approach 1:
The patent replaces the mechanical rivet connection system with a chemical bonding system using a curable connecting layer. The window frame is bonded to the fuselage skin through a curing process that creates a continuous adhesive bond, eliminating the need for discrete rivets and the associated time-consuming operations of hole drilling, deburring, and rivet installation.
Solution Approach 2:
The patent merges the window frame, connecting layer, and fuselage skin into a single integral component through the curing process. This integration creates a unified structure where the boundaries between individual elements become indistinct, resulting in a continuous load path and eliminating the need for separate connection operations.
2Ease of manufacture
If rivet joints are used to connect the window frame to the fuselage skin, then the connection process is straightforward, but the connection is discrete and requires multiple processing steps
Solution Approach 1:
The patent extracts the discrete rivet elements and their associated processing steps (hole drilling, deburring, cleaning, sealant application, rivet insertion) from the connection process. Instead, a continuous connecting layer is applied around the window opening, simplifying the connection structure to essentially three components: the window frame, the connecting layer, and the fuselage skin.
Solution Approach 2:
The patent transitions from discrete punctual connections via rivets to a continuous connection through the curable connecting layer. The connecting layer provides uninterrupted bonding around the entire window opening, creating a continuous load transfer path and eliminating the gaps and discontinuities inherent in riveted joints.
3Device complexity
If a punctual connection is used between the window frame and fuselage skin, then the connection is simple, but the window frame requires sufficient size and rigidity to ensure strength
Solution Approach 1:
The patent changes the fundamental parameter of connection continuity from discrete (rivets) to continuous (adhesive layer). This parameter change allows the connection to distribute loads across the entire bonding area rather than concentrating them at discrete rivet locations, thereby reducing the required size and rigidity of the window frame while maintaining or improving connection strength.
4Reliability
If rivet joints are used for connection, then the connection method is well-established, but the process involves multiple steps including hole drilling, deburring, cleaning, sealant application, and rivet insertion
Solution Approach 1:
The connecting layer is applied in advance around the window opening before the window frame is positioned. This preliminary action eliminates the need for subsequent steps such as hole drilling, deburring, cleaning, and sealant application, as the pre-applied connecting layer serves all these functions simultaneously when cured.
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 results in a lighter, more resilient connection with improved deformation behavior, reducing the complexity and weight of the window frame while ensuring a strong bond between the window frame and the fuselage skin.
Implementation Method 1
arranging a curable connecting layer around the window opening, pressing the window frame onto the connecting layer, hardening the composite of fuselage skin, connecting layer and window frame
Data Source
AI summary
A method for joining a window frame to a fuselage skin of an aircraft made of a fiber composite material, includes providing the window frame, making a window opening in the fuselage skin, arranging a curable connecting layer around the window opening, pressing the window frame onto the connecting layer, hardening the composite of fuselage skin, connecting layer and window opening.