Vibration reduction of helicopter tail shaft by using dry friction dampers

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2017

Author

Özaydın, Onur

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Tail Drive Shaft is a power transmission component of a helicopter which constructs the link between the main gearbox and the tail rotor. In many helicopter designs, tail shafts are working in supercritical speeds. In order to limit resonance vibrations of tail drive shaft occurring as a drawback of a supercritical design, dry friction dampers are used by helicopter manufacturers. In this study, vibration reduction of supercritical helicopter tail drive shaft by utilizing dry friction dampers is studied. Euler-Bernoulli beam theory is used to model the tail drive shaft supported by springs at both ends which represent the bearings and couplings used. Equation of motion is obtained by using Hamilton’s Principle. Obtained partial differential equation of motion is discretized by using Galerkin’s Method, and Harmonic Balance Method utilizing single harmonic is used in order to convert the resulting nonlinear ordinary differential equations into a set of nonlinear algebraic equations. These set of equations are solved by using Newton’s Method and Newton’s Method with Arc-Length Continuation. In order to model the dry friction dampers mathematically, two different friction models are taken from the literature. However, in the literature there is no mathematical model for dry friction element with gap. Therefore, in this study as an addition to the models taken from the literature a one-dimensional macroslip dry friction model with gap is developed. Several case studies are performed in order to study the effect of design parameters on the vibration amplitude of the tail drive shaft.

Subject Keywords

Helicopter tail drive shaf, Dry friction damper, Macroslip friction model, Friction., Nonlinear vibrations, Harmonic balance method

URI

http://etd.lib.metu.edu.tr/upload/12621655/index.pdf
https://hdl.handle.net/11511/26882

Collections

Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

O. Özaydın, “Vibration reduction of helicopter tail shaft by using dry friction dampers,” M.S. - Master of Science, Middle East Technical University, 2017.