Managing noise inside aircraft or within any enclosed space for that matter has been a challenge for engineers for a long time. At present, drywall, foam sheets, end-grain balsa like materials are used as sound dampeners.
The problems with these solutions are that they don’t absorb sound on the basis of their shape but on the basis of their density. If you increase the thickness of these materials, their sound absorbing power gets increased.
Hence, they become bulky and heavy. Further, manufacturing them is expensive and complicated. To give you an example, honeycomb panels are widely used in aerospace industry as sound absorber inside an aircraft. They are lightweight, too.
However, their manufacturing process is quite expensive as these structures demand to be adhesively bonded and cut in desired shape to fit inside a particular space of an aircraft.
A recent patent application by Boeing indicates a solution to these problems. The invention discloses a specially designed 3D printed sound absorbing structure.
The patent application mentions a use of thermoplastic material to manufacture these panels using fused deposition modeling technique. These panels will be placed at different section inside an aircraft.
As different locations inside an aircraft have different level of noise, sound to be absorbed in those sections vary. Thus, different locations are going to have a different sound profile.
On the basis of these sound profiles, geometrical shape and density of different layers of a sound absorbing panel will be determined. Thus, unlike conventional sound absorbers, their sizes, shape, and density will vary as per the location.
If there is any industry that’s going to get benefited out of additive manufacturing then that’s the aerospace Industry signals one of the reports by GreyB Research, a technology research, and intelligence firm, on patent filing in 3D metal printing domain. GE, for example, used additive manufacturing to produce 25% lighter and 5 times stronger fuel nozzle.
And this patent application by Boeing also signals an increasing interest of the industry in the domain.
Besides this, I would like to share another interesting invention of Boeing where it is converting airport noise into electricity.