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Wind and Structures
  Volume 18, Number 3, March 2014, pages 215-233
DOI: http://dx.doi.org/10.12989/was.2014.18.3.215
 


Identification of flutter derivatives of bridge decks using CFD-based discrete-time aerodynamic models
Zhiwen Zhu and Ming Gu

 
Abstract
    This paper presents a method to extract flutter derivatives of bridge decks based on a combination of the computational fluid dynamics (CFD), system simulations and system identifications. The incompressible solver adopts an Arbitrary Lagrangian-Eulerian (ALE) formulation with the finite volume discretization in space. The imposed sectional motion in heaving or pitching relies on exponential time series as input, with aerodynamic forces time histories acting on the section evaluated as output. System identifications are carried out to fit coefficients of the inputs and outputs of ARMA models, as to establish discrete-time aerodynamic models. System simulations of the established models are then performed as to obtain the lift and moment exerting on the sections to a sinusoidal displacement. It follows that flutter derivatives are identified. The present approaches are applied to a hexagon thin plate and a real bridge deck. The results are compared to the Theodorsen closed-form solution and those from wind tunnel tests. Satisfactory agreements are observed.
 
Key Words
    bridge flutter; CFD; discrete-time aerodynamic model; system identification; system simulation
 
Address
Zhiwen Zhu: Center of Wind Engineering, Hunan University, Changsha 410082, China
Ming Gu: State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, China
 

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