Riassunto analitico
The electrification revolution has introduced a paradigm shift in the design and research of vehicles. The initial conjecture was that the introduction of electric cars would ultimately diminish the area of NVH analysis. However, on the contrary, it has revealed an unknown and extensive domain in this field. The differences such as powertrain and packaging are the most noticeable game-changers. Removal of ICE powertrain comes at the cost of the absence of the masking noise, giving rise to other noise sources. Significant noise contribution has shifted from powertrain noise (ICEV) to road noise (BEV). It is hinted that at roughly about 50 km/hr [1], BEV is not quieter as expected because the road noise increases with speed and now becomes the dominant noise source. The most well-known technique to handle road noise is Transfer Path Analysis (TPA). This technique identifies the critical noise paths on the chassis and car body contributing to the interior noise. Different CAE practices currently used road noise prediction, such as the wheel centre force method and full FEM models; a brief comparative study will be presented. Nevertheless, the main scope of this thesis is dedicated to the prediction of structure-borne road noise by applying a merely new hybrid methodology involving both multibody and FEM together using a specific tire model CD-tire.
The Multi-disciplinary methodology[2] is based on a CAE approach that combines the finite element method and multibody simulation and uses the MATLAB postprocessing tool for the final calculation. The Multibody simulation is used to extract dynamic forces induced on to body structure via suspension system from the tyre-road interaction. The Finite element part is used to simulate the Noise transfer function generated from the FEM model, including vehicle cavity and trimmed body, representing the body. Moreover, FE is also used for generating flexible bodies used in Multibody simulations. Finally, MATLAB is implemented for final calculations and postprocessing aspects. The decoupling of different disciplines allows experts to focus on their domains. Additionally, primitive psychoacoustics analysis is also included to demonstrate the extensive functionality and efficacy of the methodology. Hence superior simulation approach is introduced, which reduces complexity and time, and guarantees reliable accuracy.
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