1,721,147 research outputs found
Stochastic energy analysis of seismic isolated bridges
No full textIn this paper, a parametric stochastic analysis of isolated bridge is proposed with the aim to assess isolation performance and to investigate effects of energetic influence on protection efficiency. The analysis has been carried out in terms of two stochastic parameters of pear-deck maximum displacement and hysteretic energy response, of which a qualitative trend has been observed. Isolated bridge is described by a simple two degree of freedom (TDoF) Bouc-Wen hysteretic model, which has been introduced for its intrinsic ability in reproducing a wide range of real devices behavior. With the aim of taking into consideration intrinsic stochastic nature of seismic events, the ground motion and the structural response have been described by random vibration approach. Results obtained show that protection achieved by shifting structural natural period and reducing input energy by devices dissipation have counteracting effects if related to deck lateral displacement
Formulazioni per una stima accurata della vita utile di elementi in c.a. soggetti ad attacchi di cloruri
No full textDifferenti criteri di ottimizzazione robusta applicati a sistemi di protezione passiva a masse attonate soggette a vibrazioni random
No full textFuzzy-Entropy based Robust Optimization Criteria for Tuned Mass Dampers
No full textTuned mass dampers (TMD) are well known as one of the most widely adopted devices in vibration control passive strategies. In the past few decades, many methods have been developed to find the optimal parameters of a TMD installed on a structure and subjected to a random base excitation process, but most of them are usually based on an implicit assumption that all of the structural parameters are deterministic. However, in many real cases this simplification is unacceptable, so robust optimal design criteria becomes a viable alternative to better support engineers in the design process. In Robust Design Optimization (RDO) approaches, indeed the solution must be able to not only minimize the performance but also to limit its variation induced by uncertainty. Most of the currently available RDO methods are based on a probabilistic description of the model uncertainty, even if in many cases they are not able to explicitly include the influence of all the possible sources of uncertainties. Therefore, in this study, a fuzzy version of the robust TMD design optimization problem is proposed. The consistency of the fuzzy approach is studied with respect to the available non-probabilistic formulations reported in the literature and an application to an example of a robust design of a linear TMD subjected to base random vibrations in the presence of fuzzy uncertainties. The results show that the proposed fuzzy-based approach is able to give a set of optimal solutions both in terms of structural efficiency and sensitivity to mechanical and environmental uncertainties
Differenti criteri di ottimizzazione robusta applicati a sistemi di protezione passiva a masse attonate soggette a vibrazioni random
No full textUn criterio per l’ottimizzazione vincolata dei Liquid Column Mass Dampers (LCMD) per la mitigazione degli effetti sismici sulle strutture
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