22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-1.8.3

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

Z. Dzygadlo, W. Perkowski
Institute of Aviation, Poland

Keywords: helicopters tail rotor drive shaft, nonlinear dynamic model, flexural vibrations analysis

In the new ultra-light helicopter, just now designed in the Institute of Aviation, a lightweight supercritical tail rotor drive shaft will be used. This paper presents a nonlinear dynamic model of such a shaft for the analysis of its flexural vibrations. The model assumes that the shaft has several deformable supports with elastic and damping elements and is loaded by external forces caused by its local unbalance. The equations of motion have been obtained making use of the finite element method and dividing the shaft into several elements between successive supports. In order to ensure easy crossing through a resonance region, a nonlinear dry friction damper has been applied in the shaft structure. Depending on the parameters of this damper, we can obtain various bending vibrations of the shaft under consideration. There can be regular or chaotic vibrations of the shaft.

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