Influence of central stabilized plate on flutter performance of truss beam section and its action mechanism
Truss beam section is widely used in the construction of long-span suspension bridges,but its section form is blunt and its aerodynamic performance is poor.Central stabilized plate is a kind of aerodynamic measure.In order to study the effect and mechanism of central stabilized plate on flutter performance of truss beam suspension bridges,free vibration wind tunnel tests were conducted on Chishui River Bridge in detail to test flutter response of segment models with and without central stabilized plate under different wind attack angles.The amplitude-dependent modal damping and flutter derivative A2* were extracted based on the test data.The experimental results show that the central stabilized plate can significantly improve the flutter performance of the section and reduce the participation of vertical degrees of freedom in the flutter.After the central stabilized plate is added,the improvement of flutter performance of the system mainly comes from the increase of uncoupled positive aerodynamic damping of the modal damping.The reason of the increase of uncoupled positive aerodynamic damping is that the stabilized plate changes the change law of A2*,so that it does not change from negative to positive and cannot provide negative aerodynamic damping all the time.The change of A2* is most significant under positive attack angle.
central stabilized platenonlinear flutteraerodynamic dampingtruss beam