Aircraft Fuselage Structural Junction Using Tension Bolts
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Solution Overview
Problem
Conventional methods for assembling the structural junction at the rear pressure bulkhead interface in aircraft or spacecraft fuselages are complex, time-consuming, and require numerous separate parts, leading to lengthy assembly processes and high costs.
Innovation Solution
The use of first and second fittings with tension bolts for a shear attachment principle, allowing pre-assembly of fuselage sections and reducing the number of parts needed during assembly, while facilitating access and load transmission through the skin, thereby simplifying the assembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fasteners such as rivets are used to transmit shear loads at the pressure bulkhead interface, then the structural connection is reliable, but the assembly process becomes complex and time-consuming
Solution Approach 1:
The invention divides the load transmission function into two separate mechanisms: shear loads are transmitted through the skin and structural members, while tensile loads are transmitted through the tension bolts. This segmentation allows each fastener to be optimized for its specific function, simplifying the overall assembly process while maintaining structural reliability.
Solution Approach 2:
The tension bolts are pre-assembled with the pressure bulkhead and fuselage sections before final assembly. This preliminary action allows for pre-positioning and alignment, reducing the complexity and time required during final assembly operations.
2Adaptability or versatility
If numerous separate parts are used for the structural junction, then the structural functionality is comprehensive, but the number of assembly operations increases significantly
Solution Approach 1:
The invention combines multiple functions into integrated components. The tension bolts simultaneously provide tensile load transmission, positioning, and alignment functions. The skin and structural members are designed to work together as a unified shear load path, reducing the need for separate fasteners for each function.
Solution Approach 2:
The tension bolts serve multiple purposes: they transmit tensile loads across the joint, provide precise positioning of the pressure bulkhead relative to the fuselage sections, and enable alignment during assembly. This multi-functionality reduces the total number of components and assembly operations required.
3Strength
If complex assembly procedures are used to ensure proper alignment and load transmission, then the structural integrity is maintained, but the assembly cost and time increase
Solution Approach 1:
The tension bolts and skin structure are designed to self-align and self-position during assembly. The geometry of the tension bolt holes and the relationship between the skin and structural members automatically ensure proper alignment and load path continuity, eliminating the need for complex alignment procedures while maintaining structural integrity.
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 approach reduces assembly lead time, improves ergonomics, and enhances the efficiency of the assembly process by allowing pre-assembly of sections and efficient load transmission, while minimizing the number of components and complexity.
Implementation Method 1
transmitting tensile loads along the skin and across the joint
Implementation Method 2
loads between adjacent fuselage sections are transmitted mainly as shear loads e.g. using fasteners such as rivets
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
There is proposed a structural junction (11) in an aircraft or spacecraft fuselage (2), comprising a first fitting (13) attached to a portion (17a) of a fuselage skin (17) in a first fuselage section (2a), a second fitting (23) attached to a portion (17b) of the fuselage skin (17) in a second fuselage section (2b), and a pressure bulkhead skin (19) attached to an inner flange (29) of the first fitting. The inner flange is spaced apart from the fuselage skin towards an inner space (10) of the fuselage. The first and second fittings are connected or configured for being connected at least using a plurality of tension bolts (37). The tension bolts each are arranged and adapted to transfer at least tensile loads, in a direction across adjacent edges (12a, 12b) of the first and second fuselage sections in a region where the first and second fuselage sections are joined, between the first and second fittings. Furthermore, the invention relates to an aircraft or spacecraft (1) comprising a fuselage including such a structural junction, and to a method of forming a structural junction in an aircraft or spacecraft fuselage. The invention may in particular contribute to reducing the number of parts and the assembly lead time during fuselage section assembly and to improving ergonomics during the assembly process.