Research On Flutter Control Method And Mechanism Of Long-span Bridge Based On Active Splitter Plate

Our country is located at the junction of Asia Europe continent and Pacific Ocean.Its unique geographical location makes our country have many islands,such as Taiwan Island and Hainan Island.Hainan Island is 20 kilometers away from China mainland,Taiwan island is more than 100 km away from China mainland,and Dalian city is 100 kilometers away from Yantai city spanning Bohai Sea.How to build super long-distance bridge may become a century problem.And wind is strong at sea,how to make the offshore super span bridge not be damaged or even collapsed due to wind in its design cycle has become the key and difficult point of design.Therefore,it is of great significance to study the flutter control method and mechanism of super long span bridges.In order to control flutter of long span suspension bridge,the active shunt plate is chosen as the control measure of flutter suppression.Based on computational fluid dynamics(CFD)software,the influence of active splitter plate on flutter stability of bridge is analyzed and studied from the phase difference between main beam and splitter plate.A pneumatic control mode under the control of active splitter plate is proposed.The main contents of this paper include the following four points:1.Based on the mathematical model used by Theodorsen in the study of wings,the contribution of the main beam movement and the movement of the splitter plate to aerodynamic force is derived from the source.The aerodynamic self-excitated model of the bridge under the control of the active splitter plate is obtained when the split plate is located at both ends of the main beam.2.After adding the shunt plate,the aerodynamic self-excited force of the system is represented by the superposition of the self-excitated force caused by the main beam movement and the self-excited force caused by the shunt plate,which results in the flutter derivative changing to 16.In this paper,the active control is used to represent the movement of the splitter plate as the motion and control rate of the main beam,and the16 flutter derivatives are changed back to 8,and a new flutter derivative expression is derived.3.In view of the concept and method of surface flutter derivatives(SFDs)proposed by Li Ke,this paper optimizes and innovates the concept and method based on it,eliminating the influence of the location change of the main beam surface sampling points on the results,and inspired by SFDs,the concept and method of pressure flutter derivatives(PFDs)are proposed.The results provide a basis for the study of the relationship between the pressure fluctuation and the motion of the main beam.4.Taking the East Bridge of the great sea belt as an example,the incremental diagram of flutter characteristics with attack angle of main beam is obtained by SFDs method.The internal mechanism of flutter stability with attack angle is analyzed,which provides guidance for active control of the splitter plate.5.The East Bridge of the great belt with active shunt plate is analyzed.The influence of active splitter on aerodynamic frequency and aerodynamic damping of main beam is analyzed from the angle of phase difference between main beam and splitter plate.The phase difference of the best control effect is found out.The increment of torsional damping of the system is analyzed by SFDs method.Finally,a pneumatic control mode under the control of active shunt board is proposed.