Alternative approaches for structural damping isolation in modal analysis for folding wings

摘要

This paper builds on two different approaches for structural damping introduction for a foldable wing concept, where the outer wing can move in flight as a load alleviation device. In modelling such a concept and exploring the parameter space, it is essential that the damping of the hinge can be varied indepedently of the damping coming from the surrounding structure. Isolating the damping on the hinge can be a very challenging problem. The first method requires the structural damping to be applied in the Cartesian coordinates, while maintaining the non-diagonal terms. The second one creates an artificial mode shape that represents the motion of the wing tip. Then, it applies modal damping on each of the mode shapes of the structure based on how well they much with the artificial mode. Both methods give very good results and present advantages and disadvantages. For the purposes of this study an inhouse aeroelasticity code was used, while the main objective of this paper is to discuss the challenges in implementing both methods, as well as the potential use for isolating structural damping on the connections of multi-bodies when a multi-body code is not present.