Investigations on the performance of a liquid column damper (LCD) with different orifice diameter ratios

An experimental investigation was carried out of the influence of the orifice in a liquid column damper (LCD) in changing the vibration-suppression characteristics of a structure subjected to earthquake excitations. An analytical solution has been presented for the transfer function of the maximum displacement of the structure, modelled as a single-degree-of-freedom (SDOF) system, with applied harmonic base motion. A standard equivalent linearization technique has been employed to cater for the nonlinear damping of the orifice in the LCD. The experimental results are validated. The performance of the orifice has been evaluated through the experimental testing of various base displacement amplitudes and frequencies. An SDOF system was built on a platform capable of generating sinusoidal excitations of predefined input frequencies and displacements. An LCD was also built with the ability to change its orifice size. Both theoretical and experimental results are plotted to examine and compare the performance of the LCD. It was observed that structural response may increase at off-resonant frequencies due to inappropriate selection of orifice ratios in some cases.