Effects of Considering In-Plane Bending Terms, on the Nonlinear Aeroelastic Behavior of the High Aspect Ratio Wings

This paper aims the effects of considering bending terms in nonlinear aeroelastic analysis of slender wings-high aspect ratio and flexible wings. The analysis is done bay using a nonlinear structural model coupled with linear unsteady aerodynamic. Wing flexibility, coupled with long wingspan can lead to large deflections during normal flight operation of an aircraft. Two wings with the same mechanical and geometrical characteristics but one with vertical/forward-afterward/torsional and the other with vertical/torsional allowed motions are juxtaposed. Third order form of nonlinear general flexible Euler-Bernoulli beam equations is used for structural modeling, Unsteady linear aerodynamic strip theory based on the Wagner function is used for determination of aerodynamic loading on the wings. Combining these two types of formulation yields nonlinear integro-differentials aeroelastic equations. Using the Galerkin’s method and a mode summation technique, the governing equations will be solved by introducing a numerical method without the need to adding any aerodynamic state space variables and the corresponding equations related to these variables of the problem. The obtained equations are solved to predict the aeroelastic response of the problem. The obtained results of both cases are compared in fields of temporal behaviors, Limit cycle oscillations, frequencies, phase planes and amplitudes.

کلیدواژه ها:

Nonlinear Slender Wing ، Limit Cycle Oscillations ، Wagner Function ، vertical/forward-afterward/torsional ، vertical/torsional