Parameter Uncertainty Effects of Stiffeners on the Vibration of Plates

The paper concerns parameter uncertainty effects of rib-stiffeners on the vibro-acoustics of thin plate structures. To gain a deep insight into the uncertainty propagation mechanism, a simple beam-stiffened plate model is built up in the first instance. By a simple mode-based hybrid technique, both the dynamic response of the beam and the statistical energy response of the plate can be approximated as functions of the beam natural frequency variations. It is found that if the amount of beam uncertainty is small enough (e.g., the generated set of natural frequency variations is narrower than the corresponding half-power bandwidth of the resonant modes), the real part of the beam mobility tends to be affected relatively little compared to the imaginary part. As a result, only the phase part of the dynamic response of the beam tends to be affected while the amplitude part can be affected relatively slightly. This is especially true when the beam and the plate have a large dynamic mismatch. One can thus deduce that, for stiffened-panel structures, the parameter uncertainties of stiffeners tend to affect little the structure-borne-sound transmission between ribs and the panel foundations. Numerical investigations of different rib-stiffened plates were conducted to validate the main conclusions.