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Advances in Acoustics and Vibration
Volume 2014, Article ID 465489, 10 pages
Research Article

Phase Portraits of the Autonomous Duffing Single-Degree-of-Freedom Oscillator with Coulomb Dry Friction

Kolektor Etra, Šlandrova Ulica 10, 1231 Ljubljana-Črnuče, Slovenia

Received 13 May 2014; Accepted 18 August 2014; Published 14 September 2014

Academic Editor: Lars Hakansson

Copyright © 2014 Nikola Jakšić. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The paper presents phase portraits of the autonomous Duffing single-degree-of-freedom system with Coulomb dry friction in its parameter space. The considered nonlinearities of the cubic stiffness and Coulomb dry friction are widely used throughout the literature. It has been shown that there can be more than one sticking region in the phase plane. It has also been shown that an equilibrium point occurs at the critical combinations of values of the parameters and which gives rise to zero eigenvalue of the linearised system. The unstable limit cycle may appear in the case of negative viscous damping ; .