Nonlinear aeroelastic steady simulation applied to highly flexible blades for MAV

A novel approach is presented to perform nonlinear aeroelastic steady-state simulations of highly flexible structures such as fix wings and rotating blades. The methodology has been developed in a specific OpenFSI service available in MSC Nastran SOL 400 [1] that includes follower forces and incremental loads features to allow for accurate nonlinear steady Fluid-Structure Interaction analysis. The new service, called HSA.OpenFSI, based on the HSA Toolkit [2], has been implemented to couple MSC Nastran to SC/Tetra solver from Cradle. Six DOF spline technology is used to interpolate data between the aerodynamic and structural grids [3]. A new approach has been designed to improve the efficiency of this technology that allows to considerably reduce the time needed to create the interpolation spline matrix and the disk space to store it. A Nastran-based FEM algorithm has been developed to take care of the fluid domain deformation. The proposed approach has been validated on a flap in a duct model, where transient steady-state results are available from other approaches [4], and then preliminary results on a proprotor two-blade model of Micro Air Vehicles MAV from ISAE [5] will be presented.