Couple-stress fluid improves dynamic response of gear-pair system supported by journal bearings

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. copyright © 2012 cai-wan chang-jian et al.