Simian Lei , Wei Cui , Luca Patruno , Stefano de Miranda , Lin Zhao , Yaojun Ge
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引用次数: 0
Abstract
Stochastic dynamic analysis frequently relies on the assumption of time independence of linear systems and the stationarity of stochastic excitations, facilitating a variety of engineering studies. Nevertheless, these assumptions may not consistently remain valid, particularly in cases of structural vibrations induced by nonstationary extreme winds, and can lead to inaccurate predictions. The excitations in these scenarios have notable nonstationary characteristics because of the unstable nature of the flow. In addition, when aeroelastic forces are considered, the combined aerodynamic-mechanical system transforms into a linear time-varying system with aerodynamic damping and stiffness that change over time. In this work, a state augmentation approach for computing the multimode vibrations of a long-span bridge under nonstationary wind conditions is presented. The methodology integrates both nonstationary turbulence-induced forces and unsteady motion-induced forces. The coupling between motion-induced forces and bridge vibrations renders the system damping and stiffness matrices both time-varying and asymmetric; this results in complex-valued modes and coupled dynamics that cannot be adequately captured by a single-degree-of-freedom (SDOF) model. The proposed multi-degree-of-freedom (MDOF) approach is a stochastic calculus-based method that avoids complex modal analysis. The statistical moments of all orders for the responses of the MDOF systems are derived via Itô's formula and the stars and bars approach. Compared with existing approaches, the new approach is both reliable and efficient, demonstrating its potential for accurate and efficient analysis of nonstationary vibrations in complex engineering systems.
期刊介绍:
Engineering Structures provides a forum for a broad blend of scientific and technical papers to reflect the evolving needs of the structural engineering and structural mechanics communities. Particularly welcome are contributions dealing with applications of structural engineering and mechanics principles in all areas of technology. The journal aspires to a broad and integrated coverage of the effects of dynamic loadings and of the modelling techniques whereby the structural response to these loadings may be computed.
The scope of Engineering Structures encompasses, but is not restricted to, the following areas: infrastructure engineering; earthquake engineering; structure-fluid-soil interaction; wind engineering; fire engineering; blast engineering; structural reliability/stability; life assessment/integrity; structural health monitoring; multi-hazard engineering; structural dynamics; optimization; expert systems; experimental modelling; performance-based design; multiscale analysis; value engineering.
Topics of interest include: tall buildings; innovative structures; environmentally responsive structures; bridges; stadiums; commercial and public buildings; transmission towers; television and telecommunication masts; foldable structures; cooling towers; plates and shells; suspension structures; protective structures; smart structures; nuclear reactors; dams; pressure vessels; pipelines; tunnels.
Engineering Structures also publishes review articles, short communications and discussions, book reviews, and a diary on international events related to any aspect of structural engineering.