Influência das vibrações do cabo na instabilidade aeroelástica de uma viga simples estaiada. / Influence of cable vibrations on the aero-elastic instability of a cable-stayed beam.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

This paper is concerned with determining wind critical velocities and post-critical vibration amplitudes in a cable-stayed beam, under wind-rain condition. It is considered the cable sag due to the dead load plus the non-linear coupling between the vibration of both the cable and the beam. Three modes are of special interest, namely the first global mode (beam bending &cable vibration), the first local mode (cable vibration &negligible beam bending) and the first torsion mode. A reduced mathematical model, with three degrees of freedom, is also developed. With regard to the modelling of the aerodynamic loads applied to the beam, it can be performed after extension of classical guidelines. The aerodynamic loads applied to the cable under rain are also taken into account. For the reduced mathematical model, equivalent damping and stiffness coefficients will be defined, which depend parametrically on the wind velocity. Non-linear terms appear due to the coupling between the cable and the beam bending vibrations, and also to the aero-elastic non-linear effects on the cable. Different unstable regimes are surveyed such as the cable galloping, the unimodal flutter in torsion and the unimodal flutter with beam bending and cable vibrations coupled.

ASSUNTO(S)

wind-rain vibration vibração viga estaiada dinâmica não-linear drapejamento flutter cable-stayed beam efeito chuva-vento non-linear dynamics

ACESSO AO ARTIGO

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