Quieter lining

German researchers are using computer simulations to perfect the acoustics inside cars without having to perform extensive tests on prototype interiors.

The roof lining has a decisive effect on the acoustics inside a car, because it reflects and amplifies noise. Linings made of porous absorbent materials such as felt or natural and synthetic fibres help to improve acoustics by resisting the propagation of sound waves. Their porous structure damps noise by creating a frictional barrier that stops air molecules from bouncing back into the car’s interior. The problem is that this roof lining is usually made up of several different types of material, making it difficult to recycle.

Scientists at the Fraunhofer Institute for Industrial Mathematics (ITWM) in Kaiserslautern have succeeded in resolving this dual challenge.

Using an acoustics simulator, they have developed a roof lining that is not only better at absorbing noise inside a car than the commonly used methods but is also made of a single type of material, and thus easily recycled.