On improving weakly coupled cavity models for vibro-acoustic predictions and design

The vibro-acoustic characteristics of a cavity based on its vibro-acoustic FE model at times do not correlate well with the corresponding measured vibro-acoustic characteristics. Structural dynamic modeling errors that are often associated with the structural domain of the cavity are the main reasons for this discrepancy. This paper addresses this issue and deals with the improvement of the vibro-acoustic FE models of weakly coupled cavities. This particular application, hitherto, has not been much addressed, though the improvement of purely structural dynamic systems has been researched a lot. An experimental example of a 3D rectangular-box cavity with a flexible plate is considered. The study demonstrates that the improvement of the vibro-acoustic FE models through FE model updating can be an effective approach to obtain more accurate vibro-acoustic predictions. The study further addresses the question whether these improved vibro-acoustic models are suitable for vibro-acoustic design. This is answered by analyzing the accuracy with which the improved vibro-acoustic FE model predicts the effects of the structural modifications. It is finally concluded that the predictions based on the unimproved vibro-acoustic models may not be reliable and can have significant error, while the improved vibro-acoustic models give an improvement in the predictive capability of the model and are also found suitable for vibro-acoustic design.