Aircraft Nacelle Acoustic Panel Assembly Using Infrared Heating
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Solution Overview
Problem
Current methods for manufacturing structural and/or acoustic panels for aircraft propulsion nacelles face challenges such as long manufacturing cycles, inability to modulate temperatures, and potential damage to complex non-planar surfaces due to uneven heating and mechanical stress during assembly, particularly with techniques like electric resistance heating and cold hydroforming.
Innovation Solution
A method utilizing infrared or laser electromagnetic radiation for selective heating of metal skins to assemble with a honeycomb structure through brazing or diffusion welding, allowing for uniform deformation and reduced thermal gradients, along with a forming step to conform the skin to the cellular structure under controlled pressure, and vacuuming to prevent oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electric resistance heating is used to assemble the panel, then the skin and cellular structure can be joined together, but the manufacturing cycle becomes long and thermal gradients cause uneven heating
Solution Approach 1:
The patent replaces electric resistance heating with infrared electromagnetic radiation heating. This substitution enables direct, rapid, and uniform heating of the skin without thermal gradients, significantly reducing the manufacturing cycle time while maintaining reliable assembly quality through controlled brazing or diffusion welding temperatures.
Solution Approach 2:
The patent changes the heating parameter from indirect electric resistance heating to direct infrared electromagnetic radiation. This parameter change allows for rapid temperature rise, uniform heat distribution, and precise temperature control, resolving the contradiction between assembly quality and manufacturing time.
2Shape
If hot forming under gas pressure is applied to shape the skin, then complex non-planar surfaces can be achieved, but local crushing of the cellular structure occurs due to non-uniform mechanical constraints
Solution Approach 1:
The patent applies preliminary infrared heating to the skin before forming under gas pressure. This preliminary action softens the skin material uniformly, allowing it to conform to complex shapes under lower pressure, thereby preventing local crushing of the cellular structure while achieving the required surface complexity.
Solution Approach 2:
The patent changes the temperature parameter through infrared heating before applying mechanical pressure. This parameter change enables the skin to be formed at optimized temperature-pressure conditions, maintaining cellular structure integrity while achieving complex non-planar surfaces.
3Temperature
If thermal bells are used to limit thermal gradients during heating, then temperature distribution can be controlled, but the device complexity increases
Solution Approach 1:
The patent replaces the mechanical thermal bell system with infrared electromagnetic radiation heating. This substitution directly controls temperature distribution through selective radiation heating, eliminating the need for complex thermal bells while achieving uniform temperature control and reducing device complexity.
4Force
If cold hydroforming is used to form the skin, then water pressure can be applied, but the risk of water leaks and bursting occurs and complex shapes cannot be formed
Solution Approach 1:
The patent changes the temperature parameter through infrared heating before applying gas pressure for forming. This parameter change enables the skin to be formed at elevated temperatures where material ductility is improved, allowing complex shapes to be achieved with lower pressures and eliminating the risks associated with cold hydroforming.
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 manufacturing time, avoids the need for thermal bells, minimizes cellular structure damage, and enables the production of complex shapes with improved mechanical properties and acoustic performance.
Implementation Method 1
the working skin is heated by infrared electromagnetic radiation so as to assemble the working skin and the cellular structure by brazing or diffusion welding
Implementation Method 2
According to an unclaimed alternative, this radiation can be laser
Implementation Method 3
The first volume of the enclosure is placed under gas pressure so as to press and hold the working skin against the cellular structure
Implementation Method 4
Vacuuming to prevent oxidation
Data Source
Figure 1~3
Figure 4~6
Figure 7~8
AI summary
The invention concerns a method and a device for manufacturing a structural and/or acoustic panel for a nacelle of an aircraft propulsion assembly. The invention involves heating, by means of a heating means (3) producing electromagnetic radiation, at least one skin (11) of the structural and/or acoustic panel in such a way as to assemble this skin (11) with a cellular structure (13) of the structural and/or acoustic panel, by diffusion brazing or welding. This heating means (3) can also be used to shape the skin (11) to the cellular structure (13) prior to assembly.