Effects of Blade-to-Blade Dissimilarities on Rotor-Body Lead-Lag Dynamics.
NATIONAL AERONUATICS AND SPACE ADMINISTRATION MOFFETT FIELD CA AMES RESEARCH CENTER
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Small blade-to-blade property differences are investigated to determine their effects on the behavior of a simple rotor-body system. An analytical approach is used which emphasizes the significance of these effects from the experimental point of view. It is found that the primary effect of blade-to-blade dissimiliarities is the appearance of additional peaks in the frequency spectrum which are separated from the conventional response modes by multiples of the rotor speed. These additional responses are potential experimental problems because when they occur near a model of interest they act as contaminant frequencies which can make damping measurements difficult. The effects of increased rotor-body coupling and a rotor shaft degree of freedom act to improve the situation by altering the frequency separation of the modes. Keywords Rotor dynamics Floquet theorem Mismatched blades Helicopter rotor blades Equations of motion.
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