| Flutter is a kind of divergent self-excited vibration,it happens because the vibrating structure can absorb energy which is greater than that consumed by the damping structure in vibration continuously from the flowing airwhich is greater than that is consumed by the damping structure in vibration. Research on the bridge flutter mainly refers to the mechanism of flutter instability and flutter critical conditions, in which the critical flutter conditions have much greater practical significance and value of the works. With the increased span and flexibility of the suspension bridge , structural stiffness is getting smaller and smaller, thus structure of the bridge becomes more sensitive to the action of wind, and it is more important because flutter can make a destructive damage in a short period of time to the bridge structure.In this thesis, based on the existing time-domain flutter analysis ,researching the problem of the long-span suspension bridge flutter with the computer simulation technologyThe main work of this thesis as follows:Discussing how to express the wind load in time domain,especially the expression of motion-excited aerodynamic force.In this thesis, the expression of motion-excited aerodynamic force adopts the form of impulse response function which is developed by Lin, transfer coefficients are obtained by matching flutter derivatives using the method of Fortran powerstation database,then the expression of motion-excited aerodynamic force can express in domain-time.Based on ANSYS / APDL language, a program is developed using for the analysis of the flutter,in which the effect of the linear and nonlinear term in the motion-excited aerodynamic force,structural geometric nonlinearity, flutter derivatives,natural attack angle of incoming flow are all considered,then compared with the results of wind tunnel tests to verify the reliability and effectiveness of the method,then combined with the Xihoumen suspension bridge,analyzing its flutter stability.
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