To investigate the transient aeroelastic responses of a folding wing during morphing motion, a time-varying aeroelastic equation in state space is presented. The structural model is established based on the component modal synthesis method. A time-dependent transformation is introduced to establish the compatibility equations. The aerodynamic force is obtained by double lattice method, and then the rational function fitting method is adopted to deduce the approximate expressions of the aerodynamic force in time domain which is used in conjunction with the structural model. The equations of motion in state space are solved using the Runge-Kutta numerical integration technique to predict the transient aeroelastic responses. The effects of the flow velocity and the morphing velocity are studied to deeply understand the aeroelastic characteristics of a folding wing. The numerical results indicate that the aerodynamic force contributes to the morphing motion. With a greater flow velocity or a slower morphing motion, the reaction moment will decrease. So a better aeroelastic performance can been obtained.

A fixed-loaded interface component mode synthesis method is presented for carrying out a dynamic analysis for a folding wing. The present method has the advantages of the fixed interface method and loaded interface method, in which the effects of the elastic and inertia force at interfaces are included and the size of dynamic problem is highly reduced through elimination of interface coordinates. It is shown in the paper that the present method is able to predict the natural frequency accurately. Further, it can be integrated with the multibody dynamic code to perform the transient dynamic analysis during the morphing process.