Prediction of surface mobility of a finite plate with uniform force excitation by structural intensity

Abstract

The prediction of the surface mobility of a finite plate by the structural intensity using finite element analysis (FEA) has been investigated. The formulation of the structural intensity in a thin plate was first introduced. Then the structural intensity vectors and rms velocity distributions of a simply-supported thin finite plate have been determined using finite element harmonic response analysis for three excitation conditions: point force excitation with an attached damper but without structural damping, point force excitation with structural damping and force excitation over a finite area with structural damping. Although the rms velocity distributions give some indication of the vibration mode at a particular frequency, the structural intensity vectors reveal the power flow pattern. Finally the surface mobility of a simply-supported thin finite plate due to force excitation over a finite area with structural damping was calculated from the total injected power determined using the structural intensity and the excitation force. The results show good agreement with the theoretical prediction of the surface mobility.