NVH-Engineering of Shock Absorber Modules 2010-01-0505
One of the main reasons for unsatisfactory perception of vehicle interior acoustics is the vibration transfer through the suspension into the vehicle body structure. The interaction between the different chassis components and between chassis components and the vehicle body plays a decisive role in vibration generation. Suspension layout, body impedance at the attachment points, body properties and interior acoustic properties are the main parameters which should be considered when optimizing chassis components in regards to NVH behavior.
In past practice, test measurements of individual chassis components were used for NVH optimization. A disadvantage of this process is that analysis and improvement of vehicle acoustics are performed in a rather late phase of development and thus involve great expenses.
A new approach to targeted acoustics improvement of chassis components will be shown based on examples of shock absorber optimization. This approach combines different well-established methods, such as running mode analysis, modal analysis and measurement of vehicle noise sensitivity. These methods were developed and adapted taking suspension specifics into account (stochastic excitation, transient operations). The installation conditions of the shock absorber in the vehicle were also taken into account during the investigation of structural characteristics (experimental and computational modal analysis). NVH analyses of the entire vehicle (sub-) system were performed and are illustrated by numerous examples.