Efficient estimation of tuned liquid column damper inerter (TLCDI) parameters for seismic control of base‐isolated structures

Abstract

This paper presents an enhanced base-isolation (BI) system equipped with a novel passive control device composed of a tuned liquid damper and an inerter (TLCDI). With the aim of reducing the seismic response of BI systems, this contribution focuses on the design of the TLCDI providing analytical solutions for the optimal TLCDI parameters, easily implementable in the design phase. The effectiveness of the proposed approach in terms of seismic response reduction and computational gain is validated by comparison with classical numerical optimization techniques. The control performance of two different base-isolated TLCDI-controlled structures is assessed by employing real-ground motion records, and relevant comparisons with both uncontrolled base-isolated structures and equipped with a conventional TLCD are presented.

Sliding TLCD for vibration control of base-isolation systems: experimental comparison with traditional TLCD and TMD

“…It is worth noting that the governing equations of the BI & STLCD system can be retrieved from the study on the use of the Tuned Liquid Column Damper Inerter (TLCDI) for BI structures [14] by assuming that the parameter characterizing the inerter, i.e., the inertance, is zero. Accordingly, the equations of motion of the BI & STLCD system are:…”

“…[ [12,15], which models the resulting turbulent eddies that cause viscous dissipation. Similarly to TLCDs, which also exhibit weakly nonlinear behavior, equivalent mechanical models can be adopted to simplify the analyses required for optimal design of the device [10,14]. In the following sections, the reliability of using an equivalent linear model is verified through experimental tests.…”

“…The sliding liquid tank is connected to the base plate through two springs (length 50mm, diameter 10mm, stiffness 0.2 N/mm) arranged in parallel. The springs and the total mass of the device were chosen according to the optimal tuning described in [14]. The dashpot depicted in the mathematical model in Figure 1 was not realized, thus, the inherent damping was estimated based on the intrinsic properties of the system.…”

“…As for the procedure to determine the parameters of the STLCD device, it is worth noting that a preliminary investigation of the corresponding fixed TLCD is unavoidable. Since, as previously mentioned, the mathematical formulation of the STLCD device can be considered as a simpler version of the TLCDI device [14], deprived of the inerter mechanism, the same damping ratio of the liquid l ] of the conventional fixed TLCD can be considered, as already numerically demonstrated in [14]. Moreover, as proposed in [14], the frequency of the liquid can be arbitrarily chosen according to the admissible liquid quantity and dimensional/structural constraints, since the task of tuning can be assigned to the spring of the STLCD device.…”

“…On the other hand, when employing a TLCD endowed with a spring-dashpot system, the tuning procedure is more versatile since the spring can be used for tuning and additional damping can be achieved by the dashpot. Notably, the equations of motion of the proposed BI & STLCD system can be retrieved from the formulation of a hybrid control strategy recently introduced by the authors, which couples the BI system with a moving variant of the TLCD connected to an inerter mechanism (TLCDI) [14]. Specifically, the mathematical model of the BI & STLCD control strategy results from neglecting the inerter characteristics by assuming a value of zero for its inertance.…”