Tire modelling for cavity noise prediction in a complete vehicle simulation environment: Evaluation of CDTire/NVH in NVH Director

Examensarbete för masterexamen
Carlsson, Maja
Idoffsson, Daniel
With an ongoing transition in industry to battery electric vehicles, interior noise will no longer be dominated by an engine sound but shift to mainly originate from road noise instead. Road noise is highly dependent on the tires however traditionally used tire models have been insufficient in accurately predicting cavity noise which is problematic due to it being highly noticeable for the customer. New tire models have arised in recent years where CDTire/NVH is one of the most prominent ones. This thesis aims to evaluate the predictive capability of CDTire/NVH in the software package NVH Director (NVHD) but also conclude whether it can be advised or not to implement it in the working procedures at Volvo Car Corporation (VCC). The evaluation was performed by comparing the performance of CDTire/NVH with the spindle load method as well as physical measurements. Primary focus of the comparisons were made on the complete vehicle, focusing on cavity noise in terms of predicted absolute values, trends and critical transfer paths. In addition to these comparisons, an evaluation of a stand alone tire were also made in order to capture the direct response. Results show that CDTire/NVH in NVHD can capture the split of the cavity modes for a stand-alone tire but with unexpected sensitivity to the load case configuration. When implemented in the complete vehicle simulation model, there are ripples in the frequency response of interface forces. Furthermore, the transfer path analysis possibilities when using CDTire/NVH in NVHD is currently more restricted and fewer than the ones available with the spindle load method. All simulation results were obtained for one tire parameterization and simplified shaker excitation was used for the stand-alone tire. Due to the challenges encountered when adding the tires to the complete vehicle model in NVHD, it was neither possible to verify the performance of CDTire/NVH in NVHD by comparison with the established spindle load method nor possible to validate the tire model against full vehicle measurements. All results obtained in this thesis were obtained with NVHD version 21.2. Consequently, it is currently not advised to VCC to implement evaluated version of CDTire/NVH in NVHD into their working procedures. However, due to the potential of using CDTire/NVH in NVHD, it is also recommended to evaluate a revised version of the software addressing the issues identified in this thesis.
CDTire, NVH, Road noise, Tire model, Hyperworks, Volvo Car Corporation
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