An Experimental Investigation of Mode Shift of Cantilever Flexible Plate Coupled with Fluid

[摘要] The vibration of a structure coupled with liquid is an important problem that has many significant engineering applications such as the bionics of flapping fin, harvest of tide energy, and the conventional areas of marine and offshore structures. It is critical to experimentally validate the dynamic parameters of structures coupled with fluid so as to accurately and efficiently model, design and develop related engineering systems. This paper presents an experimental study to quantify the shifts of multiple modes of cantilever flexible plate under water due to hydrodynamics effects. This goal is accomplished by using free-decay response measurement of a cantilever flexible plate exposed in air and submerged in water. Free-decay responses are used to identify the plate dynamic properties. The FFT, power spectrum, spectrogram, empirical modal decomposition are used to quantify plate spectrum signatures. The hydrodynamic effects of liquid on the natural frequencies and the damping of plates are characterized. A comparison between the power spectra of response and empirical mode shows a good correlation. The nonlinear hydrodynamic effects on the plate response are also discussed based on experimental results.

[关键词] Fluid-structure interactions;flexible plate;hydrodynamics effects