Free vibration numerical simulation technique for extracting flutter derivatives of bridge decks

• Published in: Journal of wind engineering and industrial aerodynamics Vol. 170; pp. 226 - 237
• Main Authors: Xu, Fuyou, Zhang, Zhanbiao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2017
• Subjects: Bridge aerodynamics; Flutter derivatives; Free vibration; Numerical simulation; Numerical simulation; Bridge aerodynamics; Free vibration; Flutter derivatives
• ISSN: 0167-6105; 1872-8197
• DOI: 10.1016/j.jweia.2017.08.018

A numerical simulation technique based on computational fluid dynamics (CFD) for determining the time-varying histories of free vibration displacements, velocities, and aerodynamic forces of bridge decks is presented. The weak coupling method is used to address the problem of fluid-structure-interaction (FSI). The flutter derivatives can be conveniently extracted using the numerically simulated displacements, velocities, and aerodynamic forces, which is similar to the procedure adopted in the forced vibration method. First, the identification accuracy of flutter derivatives is validated by comparison with the theoretical results for an ideal thin plate. Then, the flutter derivatives of two typical bridge deck sections, one streamlined and one bluff, are extracted by the proposed method. The results of the streamlined section show good agreement with other methods. However, for the bluff section, noticeable discrepancies exist between different methods. The mean angle of incidence in the free vibration method is shown to be responsible for these disagreements. The strengths of the newly-proposed approach are compared with those of the numerical and experimental forced vibration and experimental free vibration methods. This convenient and effective approach may serve as a building block for extracting flutter derivatives and better understanding of the aeroelastic responses of long-span flexible bridges. •A novel numerical simulation method is proposed to extract bridge flutter derivatives.•The accuracy of the proposed method is fully verified by an ideal thin plate.•Flutter derivatives of two typical sections are numerically identified and compared.•Superiority and inadequacies of the proposed method are comprehensively analyzed.