Optimal Flutter Suppression of Nonlinear Typical Wing Section Using Time-Domain Finite Elements Method

摘要

In this paper, the optimal time-domain finite element method is applied to the flutter suppression of a nonlinear two-dimensional typical wing section. The aeroelastic governing equations are based on the inclusion of stiffness nonlinearity in pitching motion and on the quasi-steady aerodynamics. The flutter suppression problem is formulated as a general optimization problem with equality constraints that are functions of state variables. Using the variational approach, the optimality conditions are derived and the resulting equations are discretized in time-domain. Then, by setting out the discrete equations, a set of nonlinear algebraic equations is generated, and through the Newton-Raphson method, the optimum answer is attained. The numerical results are presented in which the performance of the nonlinear optimal control system designed by the time-domain finite element technique for nonlinear aeroelastic wing sections is illustrated.