Abstract
Being able to predict the vibratory behaviour of a complex structure in the
mid-frequency field, has become nowadays a strong matter of concern in the automotive
industry. The mid-frequency field is defined as the domain where the stiff (respectively the
soft) subsystem will have a low frequency (respectively high frequency) response.
A hybrid formulation for investigating the vibro-acoustic response of a structure in the mid-frequency
field will be presented in this paper. A stochastic formulation called the Smooth
Integral Formulation, based on the classical boundary integral equations, is used to model the
high-frequency subpart of the structure. The random formulation is coupled with a finite
element formulation which models the low-frequency subpart.
The hybrid method enables to predict, in the mid-frequency field, the well separated peaks
non sensitive to any randomness and generated by the "low frequency" subsystems, as well as
a smooth trend of the strongly oscillating part of the response, due to the high frequency
behaving substructure.
Finally, the formulation will be validated and its effectiveness illustrated by running
simulations for assembled 2D structures.
Keywords - mid-frequency, hybrid method, uncertainties, boundary elements,
finite elements.