Road noise improvement of a passenger vehicle through end-to-end CAE-Simulation using Transfer Path Analysis (TPA) approach

Refined NVH performance of a vehicle is a mark of premium quality. Achieving the desired NVH performance in different vehicle operating conditions is always a Herculean task and early stage “CAE design recommendations” play crucial role in overall vehicle design development. This becomes tougher when the program is very much cost, weight and timeline sensitive. This paper explores simulation approach for addressing a major noise issue for a vehicle running at a constant speed on a rough road. The first and the most critical step is to identify the exact root cause of the issue. Hence, we propose a detailed full vehicle level “contribution analysis (CA) + transfer path analysis (TPA)” methodology (everything done through the simulation) and then go for the design recommendations to improve the performance. We used road excitation power spectral density (PSD) as the input at all the four wheels (spindle locations) calculated through MBD software. The first step i.e. contribution analysis, pointed out the dominant spindle location (out of 4 wheel-spindles) and the direction of the excitation. The second step i.e. TPA, gave the exact attachment point on the BIW with direction through which forces will be passed on to the vehicle cabin. The operational deflection shape (ODS) based on above root cause identification highlighted the weak design zone. With proposed design modifications the critical noise was reduced significantly to meet target performance level. In summary, given correct inputs, CA + TPA approach at full vehicle (FV) level in CAE simulations is very effective approach to track down any issue. This methodology can be extended to all the different CAE load cases (vehicle operating scenarios).