Abstract：An approximate energy conservation algorithm for nonlinear dynamic analysis of triangular flat shells based on co-rotational formulation finite element is derived from Generalized-α method. The numerical stability of this algorithm is satisfied by predictor-corrector iterative procedure of dynamics balance equation in each time step. Combined with computational fluid dynamics (CFD) and loose coupling algorithm, a nonlinear aeroelastic analysis process for thin shell structures is developed. The transient response of a Prandtl plane joined wing is investigated in two different flight conditions (two different dynamic pressure) based on this method. It is found that there are three balance positions in the transient response when the angle of attack is positive and dynamic pressure is large, and when static aeroelastic balance is achieved, the joined wing twists down in chord direction and bends down in span direction; when the angle of attack is positive and dynamic pressure is small, the transient response has only one balance position during vibration and the joined wing twists down in chord direction and bends up in span direction. The simulation results show that the aeroelastic transient response of joined wing is much more complicated than the monoplane, so the high-fidelity analyses should be used for the aeroelastic analysis of joined wing in the process of structure design.
