Aug 2026· Journal of Vibration and Control· 0 citations· 38 references
Abstract
This study investigates the seismic performance of rigid-block-like structures equipped with a base isolation system enhanced by an array of parallel tuned mass damper–inerter devices (TMDIs). The protected structure, a typical data-center server rack, is modeled as a rigid cabinet that may experience uplift, rocking motion, and overturning under strong ground excitation. A comprehensive mechanical model is developed to describe the coupled rocking–translational dynamics of the cabinet, the isolation base, and the attached TMDI system, including impact and failure conditions. An extensive parametric investigation is carried out by varying the isolation period, the number and mass ratio of the TMDs, as well as the inertance associated with both the isolation base and the TMDs. The dynamic response is systematically evaluated through behavior maps, which identify full-contact, rocking, and overturning regimes in selected parameter planes. Numerical simulations are performed considering two cabinets with different slenderness and three historical earthquake records with distinct spectral characteristics. The results demonstrate that the proposed protection strategy is capable of significantly enlarging the safe response region, reducing both the minimum isolation period required to prevent uplift and the maximum displacement of the isolated base. Inerters attached to the TMDs are found to be particularly effective, while base-connected inerters provide additional benefits when combined with TMDIs. The effectiveness of the system is shown to depend on cabinet slenderness and seismic input characteristics. Overall, the study highlights the potential of parallel TMDI arrays as a robust and flexible solution for enhancing the seismic response of base-isolated rigid-block structures.
This study investigates the seismic behaviour of a 10-storey shear-type building subjected to eleven near-field earthquake records while explicitly accounting for nonlinear soil-structure interaction (SSI). To improve seismic performance, a novel multiple active friction-tuned mass damper (MAFTMD) framework is proposed by integrating multiple friction-tuned mass dampers (MFTMDs) with an enhanced integral-derivative tilted (I-DT) control strategy. The nonlinear behaviour of the supporting soil is represented using the Hardin-Drnevich model, enabling strain-dependent stiffness degradation and damping effects to be captured under stiff, soft, and very soft soil conditions. The parameters of the MTMD and MFTMD configurations, along with the gains of the enhanced I-DT controller implemented in the MAFTMD system, are optimized using a multi-objective thermal exchange optimization (MOTEO) algorithm. The optimization simultaneously minimizes peak storey displacement and acceleration while satisfying inter-storey drift ratio constraints. The results demonstrate that incorporating friction mechanisms significantly enhances energy dissipation and structural response mitigation as compared to conventional MTMD systems. Furthermore, the proposed MAFTMD framework provides the most stable and effective overall performance under varying near-field earthquake characteristics and nonlinear soil conditions. The study also shows that nonlinear SSI strongly affects the performance and optimization of structural control systems. Overall, the proposed framework combines friction-based damping, active control, and nonlinear soil modelling to improve the seismic performance of mid-rise buildings under near-field earthquakes.
Morteza Akbari, M. Seifi, T. Falborski et al.· Archives of Civil and Mechan...· 0 citations
To improve the seismic performance and post-earthquake recoverability of low- and mid-rise steel frames, this study investigates the seismic performance and layout strategy of a self-centering friction damper (SCFD) through experimental and numerical studies. The SCFD combines the superelastic restoring capability of shape memory alloy (SMA) bars with the energy dissipation provided by non-asbestos organic (NAO) friction materials. Monotonic and cyclic tests were conducted to characterize the mechanical behavior of Ni–50.8 at. % Ti SMA bars and the hysteretic performance of the SCFD, based on which a numerical model of the damper was established and validated. An uncontrolled frame and four controlled frames employing diagonal, chevron, improved lower toggle-brace, and improved upper toggle-brace layouts were comparatively investigated to evaluate the effects of brace configuration, installation position, and damper quantity on seismic performance. The proposed damper exhibited an equivalent damping ratio ranging from 24% to 32%. When the SMA strain exceeded 6%, the residual deformation of the damper increased significantly, indicating that excessive SMA deformation should be avoided in practical design. Among the investigated configurations, the improved upper toggle-brace layout, combined with additional dampers installed at the first story, showed the best overall performance. Compared with the uncontrolled multi-story structure, the residual inter-story drift ratio was reduced by 76.7–93.5%, while the maximum acceleration reduction reached 28.9%. However, local acceleration amplification was observed in some cases because of the increased structural stiffness. These findings provide practical guidance for the layout design and engineering application of self-centering friction dampers in low- and mid-rise steel frames.
Lu Wang, Zhaoqun Chang, Yahui Zhang et al.· Buildings· 0 citations
Nonlinear velocity dampers (NVDs) embedded in coupling beams may enhance the seismic performance of frame–core tube structures by dissipating energy and limiting structural damage. This study evaluates the seismic performance of a 20-story reinforced concrete (RC) frame–core tube building incorporating NVD-equipped coupling beams. Parametric studies are conducted at the frequent earthquake (FE) level, and nonlinear time-history analyses are performed at the design-basis earthquake (DBE) and rare earthquake (RE) levels. The results show that wall-pier flexure is the primary contributor to damper deformation, and mid-span placement is found to be relatively favorable. The optimal damping coefficient varies with the engineering demand parameters, whether base shear, drift, or additional damping, indicating that damping coefficient should be chosen based on a balanced consideration. For the N. Palm Springs ground-motion record considered in the damage assessment, the NVD-equipped models exhibit less flexural damage than the reference model for varying damping coefficients at both DBE and RE levels. These findings provide case-specific design guidance for applying NVD-equipped coupling beams in comparable RC frame–core tube buildings.
Shen Liu, Bo Li, Hui Wang et al.· Buildings· 0 citations
Efficient and practical seismic control of structures-particularly through isolation systems-remains a significant challenge due to high implementation costs and construction complexity. Moreover, their application in retrofitting existing structures often requires extensive modifications.To address these challenges, this study proposes a novel and cost-effective seismic control system, termed the Ridge-Isolated Tuned Mass Damper (RITMD), which integrates the advantages of tuned mass damping and seismic isolation. A reduced-order two-degree-of-freedom (2DOF) model is developed to capture the coupled dynamic behavior of the primary structure and the RITMD system. An optimization framework based on the Particle Swarm Optimization (PSO) algorithm is employed to determine the optimal tuning parameters. Subsequently, closed-form design expressions are obtained using nonlinear regression analysis to facilitate practical engineering applications .The proposed approach is further extended to three-dimensional structural systems, and its performance is evaluated through nonlinear time-history analyses under bidirectional earthquake excitations. The results demonstrate that the RITMD system significantly reduces structural responses, including displacements, accelerations, inter-story drifts, torsional demands, and their corresponding root-mean-square (RMS) values.Overall, the proposed system provides an efficient, practical, and versatile solution for enhancing the seismic performance of both new and existing structures.
This paper investigates the seismic performance of a nonlinear passive control device, namely a Bi-Stable Mass Damper–Inerter (BSMDI), designed to mitigate structural displacements. The system combines a mass damper connected to the primary structure through a bistable (snap-through) nonlinear element with a grounded inerter, enabling the exploitation of both nonlinear energy transfer mechanisms and enhanced inertial effects. The main objective of the study is to assess the effectiveness of the proposed BSMDI in reducing the maximum displacement response of structures subjected to seismic excitation. The novelty of the work lies in the synergistic integration of bistable nonlinear dynamics and inerter-based inertial amplification, together with a systematic parametric investigation aimed at identifying effective configurations in terms of both bistable parameters and inertance. The study is carried out on a two-degree-of-freedom system, in which the primary structure to be protected is represented by an equivalent single-degree-of-freedom model. This system is coupled to a mass damper through a bistable element, which is in turn connected to a grounded inerter device. A comprehensive parametric study is performed by varying the dimensionless stiffness and cubic coefficients of the bistable element, as well as the inertance ratio, while keeping the damper mass ratio small. The system performance is assessed using a displacement-based index defined as the ratio between the peak response of the controlled structure and that of the uncontrolled configuration. Performance maps and corresponding optimal curves are derived for three different seismic inputs. The present results suggest that the inerter plays a crucial role in achieving effective vibration mitigation, being significantly more effective than the damper mass alone. Overall, the proposed device appears to provide an efficient solution for seismic displacement mitigation.
Remo Pacella, S. Di Nino, A. D. Di Egidio· Applied Sciences· 0 citations
Control systems such as base isolators and dampers are widely used to reduce the seismic energy input to structures. Among passive control devices, Tuned Liquid Dampers (TLDs) mitigate structural vibrations through sloshing of the contained liquid, which generates counteracting inertial forces without requiring external power. The effectiveness of TLD systems strongly depends on the selected mass ratio. This study evaluates the influence of TLD mass ratio on the seismic performance of a 10-story reinforced concrete frame building, with particular emphasis on plastic deformation demands and seismic-induced residual displacements. TLDs with different mass ratios are considered to assess their impact on interstory drift, column plastic rotations, and post-earthquake residual response. The results indicate that while increasing the mass ratio may lead to higher plastic deformation demands in certain cases, it consistently reduces residual displacements. Among the investigated configurations, a 5% mass ratio provides the most balanced performance, achieving significant reductions in residual displacement without substantial amplification of deformation demands. These findings highlight the importance of carefully tuning TLD mass ratio to achieve improved post-earthquake functionality while avoiding adverse increases in structural demand.
Birkan Dağ, Muzaffer Börekçi, M. Gençoğlu· Dicle Üniversitesi Mühendisl...· 0 citations
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