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
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.
A. D. Di Egidio, Alessandro Contento, Manuel Ferretti· Journal of Vibration and Con...· 0 citations
We use cookies to run the site and, with your consent, for analytics and to show ads.
See our Cookie Policy.
