Structural Concepts for Passive Load Alleviation

Background: Nonlinear elastic concepts like degressive springs or shape memory alloys show up a wide range usage. Linear relations are then customizable for such stiffness technologies. Objective: The aim of the structural research units is to transfer this effect of stiffnesses nonlinearities into the field of aeronautical engineering. Method: For that purpose, a structural full finite element model is set up as a reference model for all concepts. To investigate several stiffness technologies, a nonlinear elastic beam method is developed. A technology for nonlinear elastic wing structures with buckling skin panels is presented. In addition, a nonlinear bending-torsion coupling is introduced by a buckling wing segment. Viscoelastic materials are applied to the structure by a constraint layer damping attachment. Results: The presented structural concepts have a potential to alleviate the loads of maneuver and gust encounters. Constraint layer damping can be used to limit the amplitude of a chosen eigenmode.