A Methodology of Resonance Avoidance for Helicopter Rotor Blade Considering the Stiffness Characteristics of a Torsion-Type Elastic Hub.

Natural vibrations of multilayer composite beams of an elastic hub and a blade under centrifugal forces are analyzed. Sequence of calculations for the resonance diagram of a blade with a hingeless elastic hub is developed. New results obtained show the possibility of appearance of zones with "zero" dynamic stiffness of the main rotor blade at the start phase. [ABSTRACT FROM AUTHOR]