Whirling and Stability Analyses of FG-rotors with Variable Diameter Subjected to Axial Load and Torsional Torque

Document Type : Research Article

Authors

1 Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran

2 Department of Mechanical Engineering, Khomeinishahr Branch, Islamic Azad University, Khomeinishahr/Isfahan, Iran

Abstract

In this paper, whirling and stability analyses of a rotor made of functionally graded
materials are investigated. The rotor is modeled based on Timoshenko beam theory and gyroscopic
effects are considered. Diameter and mechanical properties of the rotor are considered to be variable
in longitudinal direction and the rotor is considered to be subjected to axial load and torsional torque.
In order to generalization of the modeling of bearings, each of them is replaced with four springs; two
translational and two rotational acting on two perpendicular directions. Using Newton’s second law,
the set of governing equations and external boundary conditions are derived and solved numerically
using differential quadrature method (DQM). Convergence and accuracy of the presented solution are
confirmed and effect of various parameters including power index, angular velocity of spin, value and
sign of applied axial load and torsional torque on the forward and backward frequencies and stability
of the rotor are investigated. Numerical results show that all forward and backward frequencies and
therefore critical speeds decrease by increase in power law, applying axial pressure load and torsional
torque and increase by applying axial tension force.

Keywords

Main Subjects

References

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Amirkabir Journal of Mechanical Engineering
Volume 49, Issue 4
March 2018
Pages 759-772

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