Flutter Analysis For A Long-span Suspension Bridge During Construction Considering The Nonlinearity Of Aerostatic Effect

At present,the flutter analysis of long-span bridges seldom considers the influence of static wind nonlinear effect,while the long-span suspension bridges produce significant additional angles of attack and change structural dynamic characteristics under static wind loads.These nonlinear effects on large spans what is the impact of bridge flutter stability? So far,there is a lack of in-depth research.In this thesis,Lingdingyang Bridge of Shenzhen-Zhongshan channel is taken as the engineering background.In the traditional flutter frequency domain analysis theory,a three-dimensional flutter analysis method considering the static wind nonlinear effect is developed and verified based on the full-bridge aeroelastic model wind tunnel test.The main research contents are as follows:(1)The finite element analysis model of Lingdingyang Bridge at each stage of bridge completion and main girder erection is established and the dynamic characteristics of the structure at each stage of bridge completion and construction are calculated.(2)The second development of ANSYS commercial software is carried out and the analysis program of static wind nonlinear effect of long-span suspension bridge is developed.Using three component of the wind tunnel test for Lingdingyang Bridge into the bridge state and the construction of main girder structure considering the static coefficient of three component of its nonlinearity and nonlinear finite element analysis,and no wind to get the initial wind attack angles of 0° and 3°,5°,respectively,at all levels under the action of wind speed,main girder calm wind response of the various points.(3)Using MATLAB software,the program of three-dimensional flutter frequency domain analysis of long-span suspension bridge is developed.Using state of forced vibration test method for measuring and identifying the main girder bridge and the construction state in-1°~8° to flutter derivatives under the wind flow angle of attack,on the basis of the three-dimensional flutter analysis,discusses its under different initial wind angle of attack occurs when flutter flutter critical wind speed,the size of the various modes and the modal energy contribution ratio.(4)By determining the upper and lower bounds of the critical wind speed of the flutter,and introducing the structural deformation precondition matrix and the structural dynamic characteristic precondition matrix,the additional beam angle and structure of the main beam generated by the static wind load are taken into account in the three-dimensional flutter frequency domain analysis of the long-span suspension bridge.The dual effect of dynamic characteristics changes,developed a three-dimensional flutter frequency domain analysis method that considers the static wind nonlinear effect.(5)The bridge state of the deep-sea tunnel and the typical construction state are considered.The static wind nonlinear effect will affect the critical wind speed and flutter shape of the long-span suspension bridge.