Compound Mass Liquid Column Damper for Attenuating the Vibration of the Structures

This study deals with the mitigation of the vibration of the structure using a compound mass liquid column damper (MLCD). To study the damping efficiency of the MLCD, the mathematical model of the single degree of freedom structure integrated with MLCD including the damping due to the moving mass in the horizontal portion of the damper is derived. The equivalent-damping factor of the MLCD is determined by simulating the interaction between the moving mass and the liquid using the fluid-structure interaction (FSI) technique. A 3D FSI model is solved numerically using the ANSYS Workbench-CFX package. The global search optimization algorithm is applied to find the optimum tuning frequency and the optimum mass diameter ratio over a wide range of mass ratio and excitation amplitude. The optimization issue is solved with considering the limits of the maximum displacement of the liquid and the mass. Design charts for the optimum parameters and their corresponding performance index for the mass ratio from 3% to 10% and excitation intensity from 0.1% to 2% are presented. The results obtained show that the efficiency of the MTCD to mitigate the structure vibration is higher than that for the traditional liquid damper especially for excitation intensity factor over than 1 %. The efficiency of the MLCD to reduce the structure vibration reached about 95% using the proposed optimum parameters.