Numerical Simulation And Experimental Study On Flutter Characteristics Of Long Span Suspension Bridge

Long span bridges have got great application all over the world while the sensitivity of wind-induced vibration of long span bridges has been a matter that everyone concerns.Flutter has a big danger to the safety of bridge structure.The study of flutter is of great significance for practical application.First of all,in this thesis,the cases of the wind damage and disease of the bridge structure are reviewed.The significance of this study is pointed out.Then the types of wind effects on bridges structure and function types are introduced,and the development and research status of flutter theory at home and abroad are summarized as well.Next the CFD numerical simulation technology is introduced,the basic equations of fluid motion are given,numerical simulation methods are introduced and the software used in numerical simulation is introduced as well.Secondly,the methods of turbulence simulation are introduced.The background of a large span suspension bridge engineering is introduced.Numerical models of 3 turbulence models are established by taking the main girder section as the research object.By using fluent numerical simulation,the 8 flutter derivatives of the section are successfully identified and compared with the theoretical solution.The influence of different turbulence models on recognition accuracy is studied.The effects of turbulence on the accuracy of flutter derivatives are discussed.The influence of amplitude on recognition accuracy is studied by changing the amplitude of forced vibration.Then the method of the calculation of flutter critical wind speed of suspension bridge girder by flutter derivatives is introduced.Finally,the ANSYS finite element model based on full bridge is established to analyze the dynamic characteristics of the suspension bridge.The wind tunnel test of the section model of the main beam is carried out,and the wind tunnel test is conducted on the flutter performance of the segmental model of the girder.The flutter critical wind speed of the bridge and the construction state is measured by the direct flutter method.The flutter critical wind speed of suspension bridge girder is calculated by flutter derivatives.At last,the flutter stability of the main beam is evaluated,and the aerodynamic optimization methods are proposed.