Numerical Transfer Path Analysis for NVH System-Simulation Models

Abstract

For the assessment of the Noise, Vibration and Harshness (NVH) behavior of complex systems in early phases of the development process, validated modelling methods are available that allow the prediction of structure-borne and airborne noise at system level. However, due to large model sizes, the identification of weak spots in the vibroacoustic transfer behavior and the derivation of optimization measures are highly complex, time-consuming, and mostly not practical. In the field of experimental NVH analysis, transfer path analysis (TPA) has been established as target-oriented methods for identifying vibroacoustic anomalies at system level. In this contribution, TPA methods from the field of measurement technology are selected and applied to numerical NVH system models, aiming for high accuracy and low computational effort in post-processing. The applications of the methods are shown and discussed using an elastic multi-body simulation model of a tractor drivetrain with a transient run-up of the vehicle speed as an example. The classical direct-force and component-based blocked-force TPA methods selected and adapted for this study allow for efficient calculation of the sound contributions of numerical models. At the same time, they overcome typical challenges of experimental TPA, such as exact force determination or consideration of rotational degrees of freedom. In addition, the comparison of the two methods shows that the path contributions are in general different for classical and component-based TPA and only under specific conditions the same. Both numerical TPA methods allow for the identification of weak spots in the NVH behavior in an efficient and target-oriented way.