SIMULATED STUDIES IN FE MODEL UPDATING WITH APPLICATION TO VIBRO- ACOUSTIC ANALYSIS OF THE CAVITIES

Vibration and noise in passenger vehicles have become more important factors due to customer demands and stringent regulations on the generated noise. The excitation of the structural modes causes excitation of the cavity acoustic modes depending upon the coupling between the structural and the acoustic domains. Both uncoupled, (Sung, 1981), and coupled, (Sung, 1984), finite element based procedures have been proposed for Vibro-acoustic analysis. However, the effectiveness of these approaches greatly depends on the accuracy of the predictions made using such a model. At times the deviations between the Structural FE model predictions and the measurements could be significantly large calling for improvement of the numerical models (Friswell, 1995). It is seen from the literature that a large number of methods have been proposed for structural finite element model updating and the studies conducted with focus on structural dynamic applications. However, there are no studies reported on the application of structural model updating in the context of Vibro-acoustic modeling of cavities. This paper presents a simulated comparative study about structural finite element model updating using a Direct and an Iterative method for improving the predictive capability of the Vibro-acoustic models and to evaluate the effectiveness of the updated Vibro-acoustic models for the diagnosis of the noise sources.