NONLINEAR DYNAMIC MODEL FOR FLEXURAL VIBRATIONS ANALYSIS OF A SUPERCRITICAL HELICOPTER’S TAIL ROTOR DRIVE SHAFT

摘要

In the new ultra-light helicopter, just nowrndesigned in the Institute of Aviation, a lightweightrnsupercritical tail rotor drive shaft willrnbe used. This paper presents a nonlinearrndynamic model of such a shaft for the analysisrnof its flexural vibrations.rnThe model assumes that the shaft hasrnseveral deformable supports with elastic andrndamping elements and is loaded by externalrnforces caused by its local unbalance.rnThe equations of motion have beenrnobtained making use of the finite elementrnmethod and dividing the shaft into severalrnelements between successive supports.rnIn order to ensure easy crossing through arnresonance region, a nonlinear dry frictionrndamper has been applied in the shaft structure.rnDepending on the parameters of this damper,rnwe can obtain various bending vibrations of thernshaft under consideration. There can bernregular or chaotic vibrations of the shaft.