Local Optimization Model Refinement for the Preliminary Aeroelastic Structural Design of a Transport Aircraft Wing

Kurzfassung

Within this paper, the at the DLR Institute of Aeroelasticity developed software cpacs-MONA is used to evaluate the effect of the optimization model discretization on the aeroelastic assessment of a long-range transport aircraft wing using physics-based simulations at preliminary design stage. The utilized design process can be segmented into three fundamental stages: the establishment of a parametric model for the global Finite-Element-Model (GFEM), a comprehensive loads analysis of the flexible aircraft iteratively coupled with a structural optimization. As a design variable for the structural optimization, the thickness of the shell elements of a design region from the load-bearing wing structure can be adjusted to fulfill the objective function: minimize the wing-box mass under consideration of aeroelastic constraints like control surface efficiency and allowable stress or strain values, depending on the material. The design variables can be combined to design regions to reduce the size of the optimization task. For this investigation, three different fidelity levels are generated within cpacs-MONA to explore the effect of the discretization of the design variable fields on the structural mass of the wing-box together with the influence on the elastic loads, the dynamic behavior, and the resulting aeroelastic stability of the entire aircraft.