Aircraft Door Hinge Assembly With Fastenerless Composite Bonding
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Solution Overview
Problem
Conventional aircraft door assemblies rely on labor-intensive manufacturing methods using mechanical fasteners, which add mass, inhibit homogeneity of mating surfaces, and require drilling and countersinking, limiting efficiency and weight reduction opportunities.
Innovation Solution
A door assembly featuring a stiffening structure made of thermoplastic fibre-reinforced composite materials with a fastenerless join design, utilizing Additive Manufacturing for the hinge member and a process that eliminates mechanical fasteners by using a thermoplastic polymer matrix with embedded short carbon fibres for bonding, allowing for a strong and lightweight assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If mechanical fasteners are used to assemble door components, then structural strength is ensured, but manufacturing complexity and labor intensity increase
Solution Approach 1:
The patent replaces mechanical fasteners (screws, bolts, rivets) with adhesive bonding to join door components. The bonding agent creates strong chemical and physical bonds between mating surfaces, eliminating the need for drilling, countersinking, and mechanical fastening operations, thereby reducing manufacturing complexity while maintaining structural strength
Solution Approach 2:
The patent combines multiple manufacturing operations (drilling, countersinking, fastener installation) into a single adhesive bonding process. This merging of operations simplifies the manufacturing workflow, reduces the number of steps required, and eliminates the complexity associated with mechanical fastening systems
2Reliability
If mechanical fasteners are used to attach hinge to door, then reliable connection is achieved, but mass of the assembly increases
Solution Approach 1:
The patent substitutes mechanical fasteners with adhesive bonding for attaching the hinge to the door. This replacement eliminates the mass of multiple fasteners, washers, and associated hardware while maintaining reliable connection through the bonding agent, thereby reducing overall assembly mass
3Strength
If drilling and countersinking holes for fasteners is performed, then secure fastening is enabled, but manufacturing time and labor increase
Solution Approach 1:
The patent replaces the multi-step mechanical fastening process (drilling, countersinking, fastener installation) with a single adhesive bonding operation. This eliminates time-consuming drilling and countersinking operations, significantly improving manufacturing efficiency while achieving secure fastening through the bonding agent
4Strength
If mechanical fasteners are used, then structural integrity is maintained, but homogeneity of mating surfaces is inhibited
Solution Approach 1:
The patent replaces mechanical fasteners with adhesive bonding, which allows for uniform distribution of bonding material across the entire mating surface. This creates homogeneous surface composition and consistent bonding characteristics, whereas mechanical fasteners create localized stress concentrations and disrupt surface homogeneity
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
The solution enables a strong, lightweight, and efficient door assembly with reduced manufacturing complexity and weight, improved bonding strength, and simplified assembly and maintenance, while minimizing the use of mechanical fasteners.
Implementation Method 1
adhesive bonding methods have been employed in certain applications
Data Source
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Figure 3
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AI summary
A door assembly for a vehicle, the door assembly comprising: a door; a stiffening structure fixed to a surface of the door, the stiffening structure comprising a first wall spaced apart from and substantially parallel to the surface of the door, and first side walls extending between the first wall and the surface of the door; and a hinge member comprising a base portion and a hinge arm extending from the base portion; wherein the base portion comprises a second wall and second side walls extending from the second wall, the second wall and second side walls defining a volume; at least a part of the stiffening structure is located in the volume; and outer surfaces of the first side walls are bonded to internal surfaces of the second side walls.