Abstract
Vibration control of an elastic structure subjected to horizontal harmonic excitation by using two square liquid tanks is investigated. These two modes are nonlinearly coupled with each other due to the autoparametric interaction because the natural frequencies of two sloshing modes (1,0) and (0,1) in a square tank are identical. When utilizing the autoparametric interaction of two square tanks, the performance of tuned liquid dampers (TLDs) could be significantly improved because two peaks on the both sides of the tuning frequency are simultaneously suppressed. In the theoretical analysis, the equation of motion for the structure and the modal equations for sloshing are derived considering the nonlinearity of sloshing. Then, van der Pol's method is employed to determine the frequency response curves. The influences of the system parameters, such as the aspect ratio of the tank cross-section and the liquid level, on the response curves are examined. Hopf bifurcations sometimes occur and amplitude modulated motions appear depending on the system parameters. It is found that utilizing two square tanks results in improving the performance of TLDs.
