抄録
The nonlinear vibrations of a structure coupled with water sloshing in a circular cylindrical tank are theoretically and experimentally studied.For the purpose of vibration control the liquid tank is installed on the structure subjected horizontally to a sinusoidal excitation.In the theoretical analysis, the only nonlinearity of fluid force due to large sloshing amplitude is considered.The theoretical resonance curve for the harmonic oscillation is presented when the water surface is in a state of planar motion(i.e., when the excitation is small).When the excitation is comparatively large, the resonance curve is obtained by a swept sine test in a numerical simulation.As a result, it is found that the resonance curve changes from a soft spring type to a hard spring type as the water level decreases.In the case of a large excitation, a swirl motion of water surface and an almost periodic oscillation of the structure appear in certain regions of the excitation frequencies.Also, a super-summed-and differential harmonic oscillation can occur at the tuning frequency due to the nonlinearity of the fluid force.These theoretical results agreed quantitatively well with the experimental results.
