Aircraft Fuselage Sheet Entity with Stepped Composite-Metal Joints
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Solution Overview
Problem
The connection between carbon fiber-reinforced plastic laminates and aluminum laminates in aircraft fuselages is problematic due to corrosion issues and non-optimal stress distribution, leading to potential stress peaks and mechanical property alterations at the interface, which complicates manufacturing and increases costs.
Innovation Solution
A sheet entity with a carbon fiber laminate embedded in a plastic matrix and an aluminum laminate with glass fiber layers, forming an overlap joint through an electrically insulating adhesive bond, where both laminates are stepped back to ensure identical mechanical properties and optimal stress transfer without the need for inserts, thus avoiding corrosion and simplifying manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid metallic insert (titanium or aluminum profile) is used to connect carbon and aluminum laminates, then the connection reliability is improved and corrosion is prevented, but the stress distribution becomes non-optimal with stress peaks occurring at the insert regions and manufacturing complexity increases
Solution Approach 1:
The invention extracts and eliminates the solid metallic insert from the connection structure. Instead of using titanium or aluminum profiles that create stress concentrations, the patent employs a direct laminate-to-laminate bonding approach where the carbon laminate and aluminum laminate are connected through their respective edge regions without intermediate metallic inserts, thereby removing the source of stress peaks and manufacturing complexity
Solution Approach 2:
The invention uses composite material structures on both sides of the joint: a carbon fiber-reinforced plastic laminate with glass fiber edge region and an aluminum laminate with glass fiber edge region. These composite structures enable direct bonding while maintaining structural integrity and optimal stress distribution, replacing the need for solid metallic inserts with a composite-based solution
2Object-affected harmful factors
If a solid metallic insert is used to connect the laminates, then corrosion between aluminum and carbon fiber layers is prevented, but the mechanical properties of the laminates are altered in the edge region and stress peaks occur
Solution Approach 1:
The invention introduces glass fiber layers as intermediary elements in the edge regions of both laminates. These glass fiber-reinforced edge regions serve as mediating structures that enable direct bonding between the carbon and aluminum laminates without metallic inserts, preventing galvanic corrosion while maintaining uniform mechanical properties throughout the laminate structure
Solution Approach 2:
The invention changes the material parameters at the laminate edges by replacing pure aluminum or carbon fiber layers with glass fiber-reinforced composite edge regions. This parameter change in material composition at the boundary zones enables direct bonding while preserving the mechanical properties of the main laminate bodies and preventing stress concentrations
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 solution enables an optimal stress profile between carbon and aluminum laminates, ensuring consistent mechanical properties, reducing the risk of corrosion, and simplifying the manufacturing process while maintaining aerodynamic integrity and robustness, particularly in high-force regions like underfloor areas.
Implementation Method 1
an electrically insulating adhesive bond
Implementation Method 2
an electrically insulating adhesive bond
Data Source
AI summary
A sheet entity, in particular for use as a skin panel for an aircraft fuselage, with a carbon fiber-reinforced plastic laminate and an aluminum-based metal laminate in the edge region, which are connected with one another by means of an adhesive bond, and thereby are electrically insulated from one another, and are stepped back by layers. Also disclosed is a fuselage cell of an aircraft with at least one sheet entity of this type.