Flutter performance of long-span suspension bridges under non-uniform inflow

Abstract

This study takes an ideal thin flat plate as a bridge deck section and derives its flutter derivatives at different angles of attack as well as different wind directions using computational fluid dynamics simulations. The effects of wind velocity distribution, angle of attack, and wind direction on flutter performance of a long-span suspension bridge under non-uniform inflow are then analyzed by the finite element program ANSYS. The results show that the adverse effects of higher wind velocities or larger angles of attack on the flutter performance of bridge are more remarkable than the beneficial effects of lower components when the inflow is non-uniform, leading to the reduction of flutter stability, and the decreasing range increases with the increase in non-uniformity of inflow. Moreover, the flutter critical state of bridge could be even controlled by the antisymmetric torsional modal branch if the inflow with a larger angle of attack at which the streamlined plate presents the characteristics of a bluff body acts on the two ends of bridge simultaneously. For skew wind, increasing yaw angle is favorable to the improvement of the flutter critical wind speed of bridge, but the flutter performance is mainly governed by lower yaw angles when the inflow is non-uniform.