Hybrid Substructuring for Vibro-Acoustical Optimisation: Application to suspension - Car Body Interaction

For the prediction of the vibro-acoustical vehicle behaviour up to higher frequency ranges, modal approaches are not very applicable. Hybrid frequency response function based substructuring methods are therefore proposed, in which the high modal density components are represented by experimental data, and in which the lower density components are represented by finite element models. The frequency response function synthesis of the lower denstty component can be based on modal synthesis. In this paper, an application of coupling a rear twist beam suspension with a car body is discussed. In this case the vibro-acoustical behaviour of the car body is the high density component, the low density component is the suspension finite element model. Aspects of accuracy, related to truncation, influence of rotational degrees of freedom, symmetry of the experimental matrix, and prestraining of the suspension springs are discussed. The relationship between transfer path analysis and FRF based substructuring produces an understanding of the contribution of component behaviour to acoustical interior response.