Nonparametric modeling of self-excited forces based on relations between flutter derivatives
Unsteady self-excited forces are commonly represented by parametric models such as rational functions. However, this requires complex multiparametric nonlinear fitting, which can be a challenging task that requires knowhow. This paper explores the alternative nonparametric modeling of unsteady self-excited forces based on relations between flutter derivatives. By exploiting the properties of the transfer function of linear causal systems, we show that damping and stiffness aerodynamic derivatives are related by the Hilbert transform. This property is utilized to develop exact simplified expressions, where it is only necessary to consider the frequency dependency of either the aeroelastic damping or stiffness terms but not both simultaneously. This approach is useful if the experimental data on aerodynamic derivatives that are related to the damping are deemed more accurate than the data that are related to the stiffness or vice versa. The proposed numerical models are evaluated with numerical examples and with data from wind tunnel experiments. The presented method can evaluate any continuous fitted table of interpolation functions of various types, which are independently fitted to aeroelastic damping and stiffness terms. The evaluation results demonstrate that the proposed methodology performs very well and that the relations between the flutter derivatives can be used to improve the modeling of aerodynamic self-excited forces for bridge decks.
2020
2021-03-04 14:59:47
1033
aerodynamic stability/instability, bridge aerodynamics, flutter, time-domain methods, wind loads
aerodinamična stabilnost/nestabilnost, aerodinamika mostov, omahovanje, časovne integracijske metode, vetrne obtežbe
r2
Mitja
Papinutti
70
Matjaž
Četina
70
Boštjan
Brank
70
UDK
4
624.04:004
ISSN pri članku
9
1226-6116
DOI
15
10.12989/was.2020.31.6.561
COBISS_ID
3
44979715
OceCobissID
13
961377
0
Izvorni URL
2021-03-04 14:59:52