ANALYSIS OF STABILITY CONDITIONS OF A SLENDER BEAM UNDER WIND EFFECTS USING NUMERICAL MODEL

ANALYSIS OF STABILITY CONDITIONS OF A SLENDER BEAM UNDER WIND EFFECTS USING NUMERICAL MODEL

Král, R.; Náprstek, J.

Full Article:

The paper deals with a numerical analysis of an aero-elastic system wherein the flow-structure interaction is taking place in its entire complexity. It is addressed to flowinduced vibrations and other response types termed as flutter or divergence, which arise due to fluctuating fluid forces and movement of the vibrating body. These phenomena are investigated on two different types of a slender beam cross-section. This strategy enables to model the body as a double-degree of freedom (DDOF) system. The paper demonstrates a determination of aero-elastic behavior of the body before and within the critical state. The attention is paid to the elastic stiffness, damping and other DDOF system parameters influence on the type and shape of aero-elastic stability limits. The question of aero-elastic stability with regard to external disturbances is discussed as well. The relevant bifurcation points and hysteresis in response loops as functions of the wind speed are identified. A separation curve emerges within the hysteresis loop dividing the space into trivial and post-critical regimes. The results obtained using numerical approach are described and widely interpreted physically. Extensive comparison with results obtained by both (i) analytical investigation and (ii) wind tunnel experiments is presented.

The paper deals with a numerical analysis of an aero-elastic system wherein the flow-structure interaction is taking place in its entire complexity. It is addressed to flowinduced vibrations and other response types termed as flutter or divergence, which arise due to fluctuating fluid forces and movement of the vibrating body. These phenomena are investigated on two different types of a slender beam cross-section. This strategy enables to model the body as a double-degree of freedom (DDOF) system. The paper demonstrates a determination of aero-elastic behavior of the body before and within the critical state. The attention is paid to the elastic stiffness, damping and other DDOF system parameters influence on the type and shape of aero-elastic stability limits. The question of aero-elastic stability with regard to external disturbances is discussed as well. The relevant bifurcation points and hysteresis in response loops as functions of the wind speed are identified. A separation curve emerges within the hysteresis loop dividing the space into trivial and post-critical regimes. The results obtained using numerical approach are described and widely interpreted physically. Extensive comparison with results obtained by both (i) analytical investigation and (ii) wind tunnel experiments is presented.

Palavras-chave:

DOI: 10.5151/meceng-wccm2012-18243

Referências bibliográficas

• [1] Hjorth-Hansen E., “Section model tests”. Aerodynamics of Large Bridges, Balkema, Rotterdam, 1992.
• [2] Irwin H.P.A.H., “Full aeroelastic model test. Aerodynamics of large Bridges, Balkema, Rotterdam, 1992.
• [3] Frandsen J. B., “Numerical bridge deck studies using finite elements. Part I: flutter”. Journal of Fluids and Structures 19, 171–191, 2004.
• [4] Koobus B., Farhart C., Tran H., “Computation of unsteady viscous flow around moving bodies using the k - " turbulence model on unstructured dynamic grids”. Comput. Methods Appl. Mech. Eng. 190, 1441–1466, 2000.
• [5] Shirai S., Ueda T., “Aerodynamic simulation by CFD on flat box girder of super-longspan suspension bridge”. Journal of wind engineering and industrial aerodynamics 91, 279–290, 2003.
• [6] Shimada K., Ishihara T., “Application of modified k - " model to the prediction of aerodynamic characteristics of rectangular cross-section cylinders”. J. Fluids Struct. 16 (4), 465–485, 2002.
• [7] Bisplinghoff R.L., Ashley H., Halfman R.L., ”Aeroelasticity”. Dover publications, Inc., Mineola, New York, 1996.
• [8] Simiu E., Scanlan R.H., “Wind Effects on Structures”. John Wiley Andamp; Sons, New York, 1996.
• [9] Donea J., Huerta A., “Finite Element Methods for Flow problems”. JohnWiley Andamp; Sons Ltd, England, 2003.
• [10] Tezduyar T.E., “Stabilised Finite Element Formulations for Incompressible Flow Computations”. Advances in Applied Mechanics, volume 28, 1–44, 1992.
• [11] Tezduyar T.E., Mittal S., Ray S.E., Shih R., “Incrompressible flow computations with stabilised bilinear and linear equal-order-interpolation velocity-pressure elements. Computer Methods in Applied Mechanics and Engineering”. 95, 221–242, 1992.
• [12] Shakib F., Hughes T.J.R., “A new finite element formulation for computational fluid dynamics. IX. Fourier analysis of space-time Galerkin/least-squares algorithms”, Comput. Methods Appl. Mech. Eng. 87(1), 35–58, 1991.
• [13] Král R., Pospíšil S., Náprstek J., “Experimental analysis of frequency tuning influence on the response stability of bridge girders under wind action”. In proceedings of ICWE13. Amsterdam: Dutch-FlemishWind Engineering association, 2011, CD-ROM, 2011.
• [14] Král R., Pospíšil S., Náprstek J., “Response of bluff and streamlined bridge girder in the wind as function of natural frequency tuning”. In proceedings of 5th European and African conference on Wind engineering. Firenze: Firenze University Press, 2009, pp. 309–317, 2009.

Como citar:

Král, R.; Náprstek, J.; "ANALYSIS OF STABILITY CONDITIONS OF A SLENDER BEAM UNDER WIND EFFECTS USING NUMERICAL MODEL", p-1022-1040. In: In Proceedings of the 10th World Congress on Computational Mechanics [= Blucher Mechanical Engineering Proceedings, v. 1, n. 1]. São Paulo: Blucher, 2014.
ISSN 23580828, DOI 10.5151/meceng-wccm2012-18243