Vehicle interior noise transfer function predictions applying semi-analytical, finite element and boundary element approaches

The vehicle interior noise transfer functions that affect structure-borne paths critically are analysed using three different numerical techniques, namely the fast numerical modelling, finite element and boundary element. Firstly, the interior noise transfer function predictions employing the fast numerical modelling for simple rectangular cavity model are validated by comparison to the classical finite element calculations. Secondly, the finite element model is used to construct a more realistic cavity model to determine the viability of using rectangular cavity approximation in expressing the dynamics of a practical vehicle system. Results show that the rectangular cavity approximation performs quite well overall except in a narrow frequency range. These predictions are also compared to a limited set of experimental results performed in an earlier study. Thirdly, the computational times for all three numerical methods are also examined. The analysis reveals that the pure finite element method solves faster than the mixed finite-boundary element method in which the body structure is modelled using finite elements while the cavity is represented by boundary elements. On the other hand, the fast numerical modelling technique out-performs both the finite and boundary element approaches significantly due to its inherent modal superposition approach and use of only major cavity acoustic modes.