Holistic Approach to Axle NVH Assessment and Optimization

Two trends could currently be observed in the automotive industry which are affecting NVH development for new vehicles or platforms. On the one hand many axle systems are being adjusted for new electrified architectures, on the other hand virtualization and “front-loading” of the NVH tuning can be seen. The combination of both trends is challenging for OEMs. As a leading global automotive NVH development supplier, Vibracoustic has devised unique NVH axle test rigs and virtual approaches to support OEMs on their way to superior NVH performance.

Vibracoustic employs proprietary NVH test rigs to analyze and optimize entire axles without the surrounding vehicle. Load cells at all interface points, acceleration sensors and other signal sources permit a comprehensive characterization of an axle while it is either subjected to hydraulic shake inputs at the wheel hubs or running on a dyno. Having benchmarked more than eighty axles this way, using our proprietary NVH KPIs we are able to comparatively assess any new axle and assist our customers in their NVH performance judging and optimization.

If prototype hardware is already existing, the experimental axle results are used to validate simulation models, which are enabling the NVH optimization at an early stage of the development. For ride, shake and low frequency measures usually multi body models are used. Mostly handling-oriented multi-body simulation (MBS) models are enhanced to incorporate nonlinearities like friction and amplitude dependent rubber behavior. For higher frequencies, Finite Element models of the axle system or the entire vehicle are used. Both simulation approaches can be validated by Vibracoustic NVH axle analysis – and are the basis for further NVH optimization. The development process and unique contributions by NVH axle test rigs are explained in this paper. For a broader overview of our product and solutions portfolio, see [3].