Finite element formulation of the self-excited forces for time-domain assessment of wind-induced dynamic response and flutter stability limit of cable-supported bridges

In this paper it is shown how unsteady self-excited aerodynamic forces modelled by rational functions can be introduced into a finite element beam model, using the nodal displacement degrees of freedom of the element to characterize the aeroelastic system. The time-dependent part of the self-excited forces is obtained introducing additional degrees of freedom in each node, the so-called aerodynamic degrees of freedom. The stability limit and buffeting response obtained in the time domain, using different shape functions to discretise the self-excited forces, are compared with results predicted by a traditional multimode approach. It is concluded that both the stability limit and the buffeting response can be obtained using this aeroelastic element, which implies that structural nonlinearities may be more easily introduced in time-domain analysis of the wind-induced buffeting response.