Seismic effectiveness and robustness of tuned mass dampers versus nonlinear energy sinks in a lifecycle cost perspective
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Seismic effectiveness and robustness of tuned mass dampers versus nonlinear energy sinks in a lifecycle cost perspective Emiliano Matta1 Received: 6 April 2020 / Accepted: 14 July 2020 © The Author(s) 2020
Abstract Tuned mass dampers (TMDs) and nonlinear energy sinks (NESs) are two viable options for passively absorbing structural vibrations. In seismic applications, a trade-off exists in their performance, because TMDs’ effectiveness varies with the structural stiffness while NESs’ effectiveness varies with the earthquake intensity. To investigate this trade-off systematically, a lifecycle cost- (LCC-) oriented robust analysis and design method is here proposed, in which the effectiveness of a solution is measured by the reduction it entails in the expected cost of future seismic losses. In it, structural stiffness variability is modelled using a worst-case approach with lower and upper bounds, while seismic intensity variability is inherently captured by the incremental dynamic analyses underlying every LCC evaluation. The resulting worst-case lifetime cost provides a rational metric for discussing pros and cons of TMDs and NESs, and becomes the objective function for their robust optimization. The method is applied to the design of TMDs and NESs on a variety of single- and multi-story linear building models, located in a moderate-to-high seismic hazard region. Mass ratios from 1 to 10% and structural stiffness reductions up to 4 times are considered. Results show that TMDs are consistently more effective than NESs even in the presence of large stiffness reductions, provided that structural stiffness uncertainty is considered in design. They also show that a conventional robust H∞ design provides for TMDs a solution which is very close to that obtained by minimizing the proposed LCC metric. Keywords Passive vibration absorption · Tuned mass damper · Nonlinear energy sink · Lifecycle cost optimization · Robust design · Worst-case approach
1 Introduction Dynamic vibration absorbers (DVAs) are passive control devices widely used in vibration mitigation of civil structures (Housner et al. 1997). Most applications are meant to improve serviceability conditions of slender low-damped structures under quasi-stationary excitation. Seismic applications are less common, mainly because the efficacy of passive absorption diminishes with the impulsiveness of the input and with the excursions of the * Emiliano Matta [email protected] 1
Department of Architecture and Design, Politecnico di Torino, Turin, Italy
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Vol.:(0123456789)
Bulletin of Earthquake Engineering
structural response in the inelastic range. Nevertheless, considerable effort has been made in the last decades to assess the seismic effectiveness of DVAs and to enhance it through improving existing types of device and their optimal design criteria (Luo et al. 2014a; Greco et al. 2016; Lu et al. 2018; Matta 2019a). Typically, a DVA is a single-degree-of-freedom (SDOF) mass-spring-damper system appended to the primary structure. Driven by the
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