A COMPARATIVE STUDY BETWEEN TIME-DOMAIN METHOD AND FREQUENCY-DOMAIN METHOD FOR IDENTIFICATION OF BRIDGE FLUTTER DERIVATIVES

Two data processing methods for identifying bridge flutter derivatives, time-domain method and frequency-domain method, are presented based on forced vibaration testing of sectional models in wind tunnel. An experimental setup to generate two dimentional forced vibration was developed and fixed in wind tunnel. Three sectional models were tested with this setup. A comparative study between the two methods is made based on the same experimental data. The identification reliability of flutter derivatives can be improved by introducing two or more data processing methods. Frequency-domain method has a strong ability against noises, resulting in smooth curves of flutter derivatives because a filtration procedure is included in this method; the formulation of time-domain method is relatively sensitive to signal phase difference and is apt to be disturbed by noises such that the results may be shifting or fluctuating.