Study of composite plate in water with transient and steady state motions

Hydrodynamic loading and dynamic response of a composite plate were measured inside a tow tank while the speed of the plate increased from zero to various steady-state values and remained at the steady state values. Strain responses of the plate were recorded using strain gages. To determine the effect of the composite plate with fluid-structure interaction, a stiffer and heavier aluminum plate was compared to the composite plate. The composite plate was tested under various setting angles relative to the towing direction. Some experimental data were compared to numerical results at steady state motions, and they agreed well each other. The study showed that the hydrodynamic loading was greater on the polymer composite plate than on the aluminum plate of the same size. Furthermore, the hydrodynamic force was much greater during the transient period of the increasing speed than at the final steady state speed. The ratio of the peak strain in the composite plate during the transient period to the strain at the steady state motion depended on the plate speed and the setting angles significantly. Therefore, design and analysis of composite structures moving in water should consider the hydrodynamic loading during the transient motion including fluid-structure interaction.