Vibration mitigation of structures subjected to random wave forces by liquid column dampers

The effective performance of two passive vibration mitigating devices namely tuned liquid column damper (TLCD) and tuned liquid column ball damper (TLCBD) are studied for control of wave induced vibration. The stochastic dynamic analysis of structure with and without damper is first presented in frequency domain for parametric study on the performance of both the dampers to control wave induced vibration response. The optimum performance of TLCD and TLCBD systems is further investigated to study the effectiveness of a particular damper system over the other. In order to obtain optimal damper parameters to yield the best possible TLCD and TLCBD performance under a given condition, optimization is performed by minimizing the root mean square displacement of the structure. Numerical study is taken up to explore the effectiveness of both the TLCD and TLCBD. Though there is a wide gap between structural frequency and frequency of wave load, the performances of both the dampers are found to be potential for wave vibration mitigation. The optimum performance study in general shows that TLCBD perform better than TLCD. The performances of both the damper system are further verified in time domain under random wave load. (C) 2014 Elsevier Ltd. All rights reserved.