Vibration and noise reduction on a cover for power electronics for electric vehicles with vibroacoustic metamaterials

Electric vehicles represent a particular challenge in terms of noise, vibration and harshness, since there is no masking of the combustion engine anymore. For consumer acceptance, long distances need to be covered with electric vehicle, which makes lightweight structures necessary. Consequently, vibration problems occur during operation, as lightweight structures are more susceptible to vibrations. Common measures for vibration and noise reduction add a considerable amount of mass to the vehicle, counteracting the lightweight efforts. Vibroacoustic metamaterials as a novel approach promise greater vibration reductions than common measures like Alubutyl or bitumen and are accompanied by a lower weight. This study deals with the design of vibroacoustic metamaterials for the noise and vibration reduction of a cover for power electronics of an electric vehicle. The design process is demonstrated for two different kinds of vibroacoustic metamaterials made from sheet metal and a plastic film. The structural dynamic behavior of both approaches is experimentally investigated and compared with a cover equipped with Alubutyl. The vibroacoustic metamaterial, which is made from sheet metal, is furthermore tested in a vehicle under driving condition. A reduction of tonal noise components by 11 dB is achieved within the passenger compartment.