City Research Online

Abstract

The multi-objective optimal design is considered of tuned-mass-damper-inerter (TMDI) equipped linear building frames subject to seismic excitations modeled as stationary colored random processes. The TMDI couples the traditional tuned mass-damper (TMD) with an inerter. The latter is a two-terminal mechanical device developing a resisting force proportional to the relative acceleration of its terminals by the “inertance” constant. Previous work has shown that TMDI with large inertance can outperform the classical TMD for the same attached mass, if properly tuned/designed. This performance enhancement comes, though, at the expense of increased inerter forces that need to be accommodated by the host structure. A multi-objective design framework is considered to investigate the compromise between these two competing objectives. The first objective, representing the vibration suppression efficiency, is defined using first-passage reliability criteria, considering outcrossing of failure modes related to floor accelerations, inter-storey drifts, and attached mass displacement. A linear combination of the probabilities related to these modes is taken as objective function, following current performance-based seismic design practices. The second objective, representing the strengthening of the host structure required to accommodate the TMDI forces, corresponds to the stationary inerter force. A variant of the optimization problem is also considered by adopting as secondary objective the maximum force of either the inerter or the damper utilized in the TMDI configuration. In the illustrative example different topological configurations are examined for the TMDI. Results demonstrate that the proposed framework supports a comprehensive understanding of how the TMDI design establishes a compromise between the aforementioned objectives. Connection of the inerter at a lower floor than the one immediately below the TMDI mass can lead to significant reduction of both objectives.

Publication Type:	Conference or Workshop Item (Paper)
Publisher Keywords:	tuned mass-damper-inerter; multi-objective design; first-passage reliability; stationary response; peak inerter force
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology > Engineering

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