Abstract
This paper presents a dynamic system consisting of a float, fluid and a vessel for a tuned mass damper, TMD. The mechanism of the system is very simple because of that, the system fills the vessel with fluid, and only floats the float on the fluid. A theoretical formula for a natural period of the dynamic system is derived from Euler's equation of motion with perfect fluid and the float. The natural period of system is related to the fluid density and the cross section and the mass of float mainly, and is related to the cross section of vessel inconsiderably. Some experiments show that the proposed formula of natural period is accurate and useful, and show the damping characteristic of the system.
