Easy-to-tune reconfigurable liquid column vibration absorbers with multiple cells

This study proposes a retunable liquid column vibration absorber (LCVA) that can handle a wide range of natural frequencies while maintaining its original shape. The LCVA's vertical tubes are divided into several smaller tubes (i.e., cells). Sealing a cell makes the liquid in it stand still so that only part of the liquid contained within the LCVA participates in the motion. By selecting appropriate configurations of sealed cells, the sectional area ratios of the vertical and horizontal tubes and the effective horizontal tube length are changed, which yields new natural frequencies to accommodate shifts in the natural frequency of a primary building. The proposed retunable LCVA is analytically evaluated and experimentally verified by using various patterns of sealed cells and a shake-table test to provide various natural frequencies while maintaining control performance. (paper)