Flutter of suspension bridges under nonuniform wind profiles

A parametric one-dimensional model of suspension bridges is employed to investigate the effects of arbitrary wind distribution in the onset of flutter. A total Lagrangian formulation is adopted to obtain the equations of motion expressed in terms of incremental kinematic variables and linearized about the prestressed aeroelastic equilibrium. The kinematics for the deck feature the vertical and the horizontal displacements of its elastic axis and the torsional rotations of the cross sections, the latter, are assumed rigid in their own plane. The elasto-geometric stiffness of the cables is obtained by condensing the bridge equilibrium under the self-weight in the longitudinal direction. The equations of motion are coupled with an incompressible unsteady aerodynamic defined through a set of indicial functions developed, by means of computational fluid dynamics simulations, for the cross section of the Runyang suspension bridge. The numerical treatment of the aeroelastic system of equations is performed using the finite element approach.