A co-simulation methodology to simulate the nonlinear aeroelastic behavior of a folding-wing concept in different flight configurations

A methodology to simulate the unsteady, nonlinear aeroelastic behavior of a folding-wing concept in multiple flight configurations is presented. It is based on a partitioned or co-simulation scheme, which divides the dynamical system into interacting aerodynamic and structural models. The aerodynamic model that predicts the loads is based on the unsteady vortex-lattice method. The structural model that predicts the motion of the folding wing is based on the finite-element method. The grids in the two models are non-matching. The method for simultaneously integrating the combined set of equations is based on the fourth-order predictor-corrector method developed by Hamming. The technique for transferring information between the non-matching grids is the radial basis interpolation method. This system is partially validated by showing that the predicted loads here agree very closely with numerical results based on the Euler equations for a wing with prescribed unsteady twisting and pitching motion and with analytical solutions available in the literature. Finally, a series of numerical simulations related to the aeroelastic behavior of a folding-wing concept inspired by gull wings provide new insights into flutter boundaries as a function of the dihedral angles of the inner and outer wings. The findings in this paper strongly suggest that the present numerical aeroelastic model will be a valuable computational tool for further studies of aircraft with morphing wings.