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Wind and Structures Volume 14, Number 2, March 2011 , pages 133-151 DOI: https://doi.org/10.12989/was.2011.14.2.133 |
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Transfer function approximation of motion-induced aerodynamic forces with rational functions |
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Arno Kirch and Udo Peil
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| Abstract | ||
| For a detailed investigation of the dynamic behaviour of slender bridges under wind action especially the motion-induced fluid forces should be available not only for harmonic motions but also for more general ones. If linear transfer behaviour is assumed, the force-displacement relation for almost arbitrary motions can be handled in the frequency domain using aerodynamic transfer functions. In aerospace engineering as well as in bridge engineering, these functions are usually approximated by special kinds of complex-valued rational functions which depend on complex frequencies. The quality of this approximation is evaluated for several bridge cross sections in this article. It is shown that rational functions are for some sections scarcely suitable to realistically represent the transfer behaviour of motioninduced aerodynamic forces for arbitrarily complex frequencies. | ||
| Key Words | ||
| bridges; rational function approximation; state-space model; flutter; divergence. | ||
| Address | ||
| Arno Kirch and Udo Peil : Institute of Steel Structures, Technische Universitat Carolo-Wilhelmina zu Braunschweig, Beethovenstrabe, 51, 38106 Braunschweig, Germany | ||