This paper describes methods for reducing vibration in helicopter rotor blades by determining the optimum sizes and locations of tuning masses through formal mathematical optimization techniques. An optimization procedure is developed that employs the tuning masses and corresponding locations as design variables that are systematically, changed to achieve low values of shear without a large mass penalty. The finite-element dynamic analysis of the blade and the optimization formulation require the development of discretized expression for two performance parameters the modal shaping parameter and the modal shear amplitude. Matrix expressions for both quantities are derived in this paper. Three optimization strategies are developed and tested. The first is based on minimizing the modal shaping parameter, which indirectly reduces the modal shear amplitudes corresponding to each harmonic of airload. The second strategy reduces these amplitude directly, and the third strategy reduces the shear as a function of time during a revolution of the blade. The first strategy works well for reducing the shear for one mode responding to a single harmonic of the airload for has been found in some cases to be ineffective for more than one mode. The second and third strategies similar results and show excellent reduction of the shear with a low mass penalty.
Optimal placement of tuning masses for vibration reduction in helicopter rotor blades
Optimale Plazierung für die Auswuchtgewichte zur Schwingungsreduzierung in Helikopter-Schaufelblättern
AIAA Journal ; 28 , 2 ; 309-315
1990
7 Seiten, 9 Bilder, 5 Tabellen, 21 Quellen
Article (Journal)
English