The aerodynamics of a helicopter main rotor blade significantly contribute to the structural dynamics of the blade. In particular, aerodynamics provide a very strong damping force in the flap direction. Further complicating the structural dynamics of a helicopter blade are the large centrifugal forces that greatly stiffen the blade. Any complete health monitoring system for rotor blades must incorporate both of these effects. In this paper, a modal-based damage detection algorithm is developed and analytically validated. Previous work in this area has yielded an algorithm to simultaneously detect mass and stiffness changes in a rotating structure. This paper extends that analysis to a state-space approach that is capable of detecting changes in damping. For completeness, the aerodynamic forces on a hovering rotor blade are considered and the appropriate damping matrix is derived. The damping matrix is used to complete a finite element model of an S-76 rotor blade. This model is intentionally perturbed to obtain 'damaged' modal test data. This is used to analytically test the validity of the eigenstructure methodology with reasonable success.
Effects of aerodynamic damping on damage detection in helicopter main rotor blades
1999
9 Seiten, 13 Quellen
Conference paper
English
The Effects of Aerodynamic Damping on Damage Detection in Helicopter Main Rotor Blades
British Library Conference Proceedings | 1999
|Fully integrated aerodynamic/dynamic optimization of helicopter rotor blades
Tema Archive | 1992
|