Assembly of a tire and a vehicle model to predict vibrations at the bushings

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Examensarbete för masterexamen
Master Thesis
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Publicerad
2018
Författare
Westers, Michael
Johan, Rosholm
Modellbyggare
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This Master’s thesis targets the prediction of vibrations at the bushings of vehicle rear chassis due to an excitation at the tire patch for early analysis in the devel-opment stage at the Volvo Car Group. In the past a hybrid model has been used, which included a FEM model of a new vehicle design proposal and through mea-surements obtained spindle forces of an existing tire vehicle combination. However it is reasonable that these forces are di˙erent for a new tire vehicle coupling. In this thesis the measurement data is replaced by a modal tire model, which is provided by Continental AG, to become independent of testing existing vehicles. Recep-tance Coupling is used to assemble one tire to the vehicle in the frequency domain. Thereby the vibration levels at a chosen bushing are obtained due to an excitation at the tire patch for seven di˙erent harmonic excitation cases. In addition, a great focus is set on the sensitivity of the coupled solution to modal truncation errors in the tire model. Therefore an error metric is developed, which assesses the similar-ity between two FRFs using a floating bandwidth. As a result a minimum number of modes required for a desired frequency range and excitation case is given. In a second investigation uniform distributed random noise between ± 10 percent is added to the transfer functions of the tire and the vehicle model. The results show a deviation up to around 5 dB above the non-polluted case, for the major part of the frequency range, for some frequencies the coupled result show a greater sensitivity with deviation up to 20 dB for certain noise matrices.
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Ämne/nyckelord
Building Futures, Akustik, Building Futures, Acoustics
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