Efficient nonlinear aeroelastic analysis of a morphing wing via parameterized fictitious mode method

The folding wing, as a possible concept for designing morphing aircraft, has gained special attention. However, such a wing may encounter complex nonlinear aeroelastic effects with bilinear-hinge stiffnesses during the in-flight morphing process. This paper presents a novel parameterized nonlinear aeroelastic modeling methodology, based on the substructure synthesis of the folding wing with fictitious mass in hinge joints and piecewise-linear theory. The most attractive feature of the present methodology is that the nonlinear aeroelastic dynamics of the wing can be efficiently represented by piecewise, parameterized, linear subsystems using the parameterized fictitious mode method. To demonstrate the accuracy of the present method in representing the nonlinear dynamics of the morphing wing, a folding wing with bilinear stiffness in both fuselage-inboard and inboard-outboard hinges was selected as a numerical example. The numerical results demonstrate that the natural modes of each linear subsystem, as well as the limit-cycle oscillations of the folding wing at different folding angles, can be accurately predicted. In addition, a comparison between the time cost of the present parameterized method and the direct nonparameterized method was made. The comparison showed that the parameterized, nonlinear, aeroelastic modeling methodology provides an efficient way to analyze the nonlinear aeroelastic responses of a morphing wing with bilinear-hinge stiffness.