Event-triggered semi-active TLCD for ground motion-induced vibration control

One potential drawback of tuned liquid column dampers (TLCDs) is their relatively low control efficiency during the initial stage of structural vibration caused by external excitations. This is because satisfactory control effects can only be achieved when the liquid inside TLCD is fully oscillating, which is not the case during the initial stage. To solve this problem, in this study, an event-triggered semi-active technique is creatively proposed to improve the vibration reduction efficiency of TLCDs during the initial stage. The fundamental idea of the proposed approach is to provide an initial displacement to the liquid column via baffles, and then release the constraints on the initial liquid displacement at an appropriate time to achieve the rapid activation of TLCDs. A strategy from the standpoint of phase difference between liquid column motion and structural motion is proposed to determine the triggering conditions (i.e., when to release the constraints). The effectiveness of the proposed semi-active system is examined under both harmonic and stochastic excitations. The results show that the proposed strategy successfully improves the vibration suppression performance of TLCDs in the early stage of structural vibration.