Vertical-horizontal vibration control using a novel tuned liquid column mass damper (TLCMD) system : nonlinear coupling dynamics

Abstract

Although conventional tuned liquid column dampers (TLCDs) are effective for horizontal vibration control in structures, their lack of vertical damping mechanisms may restrict their effectiveness in engineering applications, where vertical vibration suppression is also critical. To address this gap, this study proposes an enhanced TLCD system by integrating spring elements in the vertical direction. This new vibration control system integrates the damping mechanisms of TLCDs in the horizontal direction and tuned mass dampers (TMDs) in the vertical direction, it is thus termed tuned liquid column mass damper (TLCMD) in the present study. The basic design of this study involves deriving the equations of motion for TLCMDs using Lagrangian mechanics, followed by rigorous validation of the analytical model through computational fluid dynamics (CFD) simulations. Comprehensive parametric analyses are conducted to investigate the nonlinear system response, examining cases both with and without the effects of negative liquid stiffness. These analyses reveal that the occurrence of negative liquid stiffness can degrade the horizontal control efficiency of the TLCD component. Finally, numerical simulations of a TLCMD-bridge system under stochastic seismic excitations are performed to evaluate the vibration reduction performance of the proposed hybrid damper in both vertical and horizontal directions. Notably, numerical results indicate that, under seismic excitations, the proposed TLCMD achieves, on average, a reduction of 40 % in the root mean square (RMS) vertical displacement and 20 % in the RMS horizontal displacement of the bridge, highlighting its effectiveness in mitigating both vertical and horizontal vibrations. These results establish the TLCMD as a practical, analytically predictable device for simultaneous vertical and horizontal vibration control and provide new insight into nonlinear interaction mechanisms in orthogonal TLCD-TMD systems.