New Unified Approach for Aeroelastic Analyses Using Approximate Transfer Functions of Aerodynamic Forces


Kilje Jung, Ho-Kyung Kim, M.ASCE; and Hae Sung Lee



 A unified approach for the aeroelastic analysis of bridge decks is presented. The structural aerodynamic transfer functions are approximated using a second-order polynomial with the coefficients determined through minimization of the weighted error between the exact and approximate transfer functions. The exact aeroelastic transfer function is used as the weighting function to define the weighted error. Using the proposed approximation, the dependence of the structural aerodynamic transfer function on frequency is eliminated, and a popular time-marching algorithm is adopted for aeroelastic analysis in the time domain. For the frequency-domain analysis, a complete set of modal frequencies and modal shapes can be evaluated in a single eigenvalue analysis. The efficiency of the analysis is enhanced with the truncated modal decomposition in the structural eigenvector space. The proposed method is verified for an idealized cable-supported structure with two extreme types of deck sections. Approximating the structural aerodynamic transfer function works well, even in the case of a bluff H-type section. The proposed method substantially simplifies the aeroelastic analysis procedure, while yielding consistent results for frequency- and time-domain aeroelastic analyses by using the same equation of motion.

KEY WORDS : Aeroelastic analysis; Aerodynamic forces; Transfer function; Unified approach; Time domain; Frequency domain; Minimization; Weighting function; Flutter derivative; Bridge.

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