Efficiency of tuned mass dampers with uncertain parameters on the performance of structures under stochastic excitation

Summary In a previous study, the authors studied a partial mass isolation (PMI) system that through isolating different portions of story masses can provide a building with multiple inherent vibration suppressors. It was shown that the PMI strategy with isolated mass ratios (IMRs) of 0.05 or 0.90 could perform as effectively as an equivalent tuned mass damper or a base isolation system, respectively. In the present paper, the PMI system is examined in structural models with different fundamental periods. PMI configurations in a wide IMR range of (0.05:0.025:0.90) are optimized illustrating that applying an IMR of 0.25–0.50 can provide an efficient system, simultaneously satisfying the constraints related to different performance objectives (i.e., mitigating the overall building seismic responses and controlling isolated components' (ICs) responses while integrating these components into the building architecture). Simulation results reveal that using identical ICs at different stories, which have the advantage of facilitating the design and construction of the system, can lead to a near‐optimal solution. It is also demonstrated that in terms of the spatial distribution of ICs, an adequate seismic performance improvement can be achieved by allocating ICs only at a subset of upper stories (e.g., top half stories), which can further simplify the PMI systems' construction.

Section: Ground Excitationmentioning

confidence: 90%

Partial mass isolation system for seismic vibration control of buildings

Anajafi

Medina

2017

“…In the latter cases, appropriate reduced‐order models are preliminarily necessary so as to reduce the computational effort before the tuning procedure. Although all these more accurate procedures are preferable, most of the literature studies dealing with the TMD tuning address only a single mode of vibration in a simplified way, especially in the context of framed buildings and earthquake excitations like the ones considered in this paper, see, for example, previous studies . A simplified way to extend the optimal design of the TMD to MDOF systems, which neglects the higher order modes of the superstructure, has been described in De Domenico et al and is adopted here.…”

Section: Optimal Design and Tuning Proceduresmentioning

confidence: 99%

Improving the dynamic performance of base-isolated structures via tuned mass damper and inerter devices: A comparative study

Domenico

Ricciardi

2018

122

The dynamic performance of base-isolated buildings can be improved by introducing a tuned mass damper (TMD) at basement, below the isolation floor where most of the earthquake-induced displacement demand is concentrated. In order to enhance the effectiveness of the TMD without simultaneously amplifying the relevant mass ratio, the use of supplemental inertial mass dampers has been envisaged by the authors and other authors in earlier studies. These schemes exploit the mass-amplification effect of the inerter, a twoterminal device whose generated force is ideally proportional to the relative acceleration between its terminals. In this paper, we present a review along with a systematic comparative study of six different strategies proposed in the literature, each one featuring a specific combination of mass-spring-dashpot elements arranged in series or in parallel with an inerter for the displacement mitigation of base-isolated structures. Frequency-response functions of each model are derived in closed form. Optimal design is based on a common strategy, considering a white-noise random process as seismic input, by minimization of the displacement variance but with an eye also for the superstructure acceleration (associated with forces arising in the superstructure) and for the TMD stroke. Then, the seismic performance of the six systems is assessed considering an ensemble of 52 natural earthquake ground motions, by comparing several response indicators including TMD stroke, deformation of the baseisolation floor, superstructure acceleration, interstory drifts, base shear, and reactions associated with spring, oil damper, and inertial damper supporting the TMD, which are significant for outlining preliminary economic assessments.

“…In order to obtain effective control strategy, many optimal design methods of TMD have been proposed to suppress the undesirable structural vibrations induced by winds and earthquakes . It is well known that the effectiveness and robustness of the TMD rely largely on its mass ratio to the host structure.…”

Section: Introductionmentioning

confidence: 99%

“…In order to obtain effective control strategy, many optimal design methods of TMD have been proposed to suppress the undesirable structural vibrations induced by winds 3,4 and earthquakes. [5][6][7] It is well known that the effectiveness and robustness of the TMD rely largely on its mass ratio to the host structure. However, due to the practical reasons, the TMD mass ratio is limited to several percent of the modal mass of the total structure, which attenuates the robustness of the TMD to the uncertainties in dynamic characteristics of the structure and the external excitations, making it difficult for the TMD to be used for large seismic vibration control.…”

Section: Introductionmentioning

confidence: 99%

Optimal design of TVMD with linear and nonlinear viscous damping for SDOF systems subjected to harmonic excitation

Huang

Hua

Chen

et al. 2019

Summary This paper investigates the optimal design of the tuned viscous mass damper (TVMD) with linear and nonlinear viscous damping properties for a single degree‐of‐freedom structure subjected to harmonic excitation. The TVMD consists of a parallel‐connected inerter and viscous damper, and a spring that mounts them to the structure. To examine the vibration control performance of the TVMD, both theoretical analysis and numerical optimization are conducted to obtain the optimal parameters of the TVMD with either linear or nonlinear viscous damping. The influence of the damping exponent of the nonlinear viscous damper on the optimal parameters and performance of the TVMD is analyzed. The results show that much better control effectiveness and robustness can be achieved by the TVMD when compared with tuned mass damper (TMD). Furthermore, it is also of great practical importance to show that the static deformation of the supporting spring due to the self‐weight of the inerter is only a small fraction of the traditional TMD in case of vertical vibration control. Compared with the linear TVMD, the nonlinear TVMD can achieve comparable or even slightly better control performance. The optimal damping coefficient depends largely on the damping exponent, and the loading intensity fluctuation also has an influence on the performance of the nonlinear TVMD. Moreover, it is shown that that the nonlinear TVMD with damping exponent ν = 2 has the best control performance on the peak displacement response of the main structure, and the TVMD with linear viscous damping optimized for the harmonic excitation can also effectively suppress the wind‐induced vibration.