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Indexed by:期刊论文

Date of Publication:2014-09-15

Journal:ENGINEERING STRUCTURES

Included Journals:SCIE、EI、Scopus

Volume:75

Page Number:418-428

ISSN No.:0141-0296

Key Words:Bridge; Flutter derivative; Coupled free vibration method; Implied approximation; Error analysis

Abstract:In the identification of flutter derivatives using coupled free vibration technique, the influences of implied approximations are assessed in this study. For a thin flat plate section and three representative deck sections of long-span bridges, KH*(1). KH*(2), KAI*(1), KA*(2), K2H*(3), K2H*(4), K(2)A*(3) are demonstrated to be dependent on reduced wind velocity, especially at lower reduced wind velocities. This is contrary to the commonly used assumption of these parameters being constants. ICh is conventionally used to quantify H*(1), H*(4), A*(1), A*(4), and K-alpha for H*(2), A*(2), H*(3), A*(3). This means the direct components of aeroelastic motions (h(1,) alpha(2)) are comparatively predominant than the incentive cross components (h(2), alpha(1)). However, this approximation is only valid for weak modal coupling cases at lower wind velocities. Novel perspectives are provided regarding the subtle underlying complexities in extracting flutter derivatives using coupled free vibration technique. The accuracy in identifying flutter derivatives can be effectively improved by setting close frequencies of coupled modes. The mechanical damping ratio, mass, and mass moment of inertia can be artificially increased to postpone the occurrence of flutter and extend the reduced wind velocity region to acquire sufficient flutter derivatives for flutter analysis. This study may serve as a building block for improving the understanding of flutter derivative identification from coupled free vibration responses, and practical strategies are proposed to improve the identification accuracy. (C) 2014 Elsevier Ltd. All rights reserved.