Journal of Applied Mathematics
Volume 2012 (2012), Article ID 527878, 20 pages
Research Article

Couple-Stress Fluid Improves Dynamic Response of Gear-Pair System Supported by Journal Bearings

1Department of Mechanical and Automation Engineering, I-Shou University, 1, Section 1, Syuecheng Rood, Dashu District, Kaohsiung 84001, Taiwan
2Department of Mechanical and Automation Engineering, Kao Yuan University, Kaohsiung 82151, Taiwan

Received 6 July 2011; Accepted 18 August 2011

Academic Editor: Nazim I. Mahmudov

Copyright © 2012 Cai-Wan Chang-Jian et al. 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.


A systematic analysis of the dynamic behavior of a gear-bearing system with nonlinear suspension, couple-stress fluid flow effect, nonlinear oil-film force, and nonlinear gear mesh force is performed in the present study. The dynamic orbits of the system are observed using bifurcation diagrams plotted using the dimensionless rotational speed ratio as a control parameter. The onset of chaotic motion is identified from the phase diagrams, power spectra, Poincaré maps, Lyapunov exponents and fractal dimension of the gear-bearing system. The numerical results reveal that the system exhibits a diverse range of periodic, subharmonic, quasiperiodic, and chaotic behaviors. The couple-stress fluid would be a useful lubricating fluid to suppress nonlinear dynamic responses and improve the steady of the systems. The results presented in this study provide some useful insights into the design and development of a gear-bearing system for rotating machinery that operates in highly rotational speed and highly nonlinear regimes.