Deformable Junction Element for Aircraft Nacelle Lip and Pipe Assembly
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Solution Overview
Problem
The existing aircraft nacelle assembly methods face challenges with high manufacturing costs and extended assembly times due to tight tolerance intervals, and previous solutions that increase tolerance intervals lead to increased costs and assembly duration, while also lacking relative movement between subassemblies which can result in damage during impacts.
Innovation Solution
Incorporating a deformable junction element, or bridge, between the lip and pipe subassemblies that allows for relative movement and shock absorption, made of materials with high elongation coefficients like titanium, which can absorb impact energy and promote rupture in case of excessive stress, thereby reducing maintenance and repair costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If tight tolerance intervals are used for subassembly dimensions to enable direct assembly, then assembly precision is improved, but manufacturing costs and assembly time increase
Solution Approach 1:
The patent changes the dimensional parameters of the subassemblies by introducing a junction element that absorbs dimensional dispersions. This allows the lip and pipe subassemblies to have larger tolerance intervals while still achieving proper assembly, as the junction element compensates for the dimensional variations through its deformable properties.
Solution Approach 2:
The junction element acts as an intermediary component between the lip and pipe subassemblies. It mediates the connection by absorbing dimensional differences and providing a flexible interface that accommodates tolerance variations, thereby enabling assembly without requiring tight tolerances on the main subassemblies.
2Ease of manufacture
If tolerance intervals are increased to reduce manufacturing costs, then manufacturing precision deteriorates, but assembly time increases due to need for compensating blocks
Solution Approach 1:
The junction element is designed with specific material properties (high elongation coefficient) that allow it to change its dimensions to accommodate tolerance variations. This parameter change capability enables the use of larger tolerance intervals while avoiding the need for additional compensating blocks, thus reducing both manufacturing costs and assembly time.
Solution Approach 2:
The junction element is designed to be a sacrificial component that can be replaced if damaged during impact events. By discarding the junction element rather than the entire subassembly, maintenance costs are reduced and repair time is minimized, while allowing for larger operational tolerances.
3Strength
If rigid direct connection is used between subassemblies, then structural strength is improved, but impact damage risk increases due to lack of relative movement
Solution Approach 1:
The junction element introduces dynamic characteristics to the otherwise rigid connection between subassemblies. Its deformable nature allows it to absorb impact energy through elastic and plastic deformation, providing relative movement capability while maintaining structural integrity during normal operation. This dynamic behavior enhances impact resistance without compromising structural strength.
Solution Approach 2:
The junction element serves as a pre-installed cushioning element between the lip and pipe subassemblies. Its high elongation coefficient material properties enable it to absorb impact energy before the force can propagate to the main subassemblies, thereby protecting them from impact damage while maintaining structural strength during normal use.
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 deformable junction element enables assembly with greater dimensional tolerances without additional blocks, reduces the risk of damage during impacts, and minimizes maintenance and repair costs by absorbing impact energy and promoting controlled rupture.
Implementation Method 1
a deformable junction element, or bridge, between the lip and pipe subassemblies that allows for relative movement and shock absorption, made of materials with high elongation coefficients like titanium, which can absorb impact energy
Data Source
AI summary
An aircraft nacelle includes a first subassembly consisting of a pipe (112) channeling an airflow in the direction of an engine having a covering or panel (118) for acoustic treatment, including, from the inside to the outside, a reflecting layer (120), at least one cellular structure (122), and at least one acoustically resistive structure (124) forming the aerodynamic surface of the pipe (112), as well as a second subassembly consisting of a lip (116) and a front frame (126), characterized in that it includes at least one connection element (134) which is separate from the two subassemblies and connected to a portion of the pipe (112) and to a portion of the lip forming an extension of the portion of the pipe at different points so as to be capable of enabling a relative movement between the two subassemblies.