Interval Finite Element Analysis of Wing Flutter.pdf

Chinese Journal of Aeronautics Chinese Journal of Aeronautics 21(2008) 134-140 /locate/cja Interval Finite Element Analysis of Wing Flutter Wang Xiaojun*, Qiu Zhiping Institute of Solid Mechanics, Beijing University of Aeronautics and Astronautics, Beijing 100083, China Received 13 July 2007; accepted 18 December 2007 Abstract The influences of uncertainties in structural parameters on the flutter speed of wing are studied. On the basis of the deterministic flutter analysis model of wing, the uncertainties in structural parameters are considered and described by interval numbers. By virtue of first-order Taylor series expansion, the lower and upper bound curves of the transient decay rate coefficient versus wind velocity are given. So the interval estimation of the flutter critical wind speed of wing can be obtained, which is more reasonable than the point esti- mation obtained by the deterministic flutter analysis and provides the basis for the further non-probabilistic interval reliability analysis of wing flutter. The flow chart for interval finite element model of flutter analysis of wing is given. The proposed interval finite element model and the stochastic finite element model for wing flutter analysis are compared by the examples of a three degrees of freedom airfoil and fuselage and a 15o sweptback wing, and the results have shown the effectiveness and feasibility of the presented model. The prominent advantage of the proposed interval finite element model is that only the bounds of uncertain parameters are required, and the probabilistic distribution densities or other statistical characteristics are not needed. Keywords: wing flutter; flutter speed; uncertainty; interval analysis 1 Introduction* The flutter of wing is a kind of self-excited vi- bration which involves interactions of inertial, elas- tic and aerodynamic forces. The flutter speed is an important assessment index for the dynamic stabil- ity of wing[1]. During design phase, the f