In this work we present basic approaches of building a sequentially coupled model of the alternator to evaluate the vibro-acoustic response resulting from different excitations, such as engine vibration, rotor unbalance and magnetic forces. A special emphasis is given to the set-up and verification of the three-dimensional (3D) structural finite element (FE) model for the whole alternator and for the alternator components. The verification of structural model was carried out by using the experimental modal analysis (EMA), which was applied also for the estimation of the modal damping and for the structural FE model updating. A special emphasis is given to the evaluation of magnetic noise, generated due to the magnetic force excitation in the alternator. To estimate the magnetic forces and their harmonic components a 3D magnetic FE model of the alternator was prepared. Finally, the exciting magnetic forces, calculated for specific operation conditions of the alternator, were transferred into a structural FE model, where structural and acoustic responses were calculated and analysed.
Head of Laboratory for noise, vibration and durability