A novel method to evaluate the journal bearing forces with application to flexible rotor model

In this work, a novel method to evaluate the nonlinear bearing forces is introduced. The method depends on using polynomial surface fitting to evaluate the bearing forces as a function of the journal center position. Then, these forces are used to investigate the stability and bifurcations of an elastic rotor-bearing model. The Hopf bifurcation analysis and limit cycle continuation are investigated using the proposed analysis for obtaining the bearing forces for un-grooved bearing with L/D = 0.5. The stability results are compared with short bearing approximation at several shaft flexibilities. In addition, the present obtained threshold speed is compared with that computed using bearing coefficients method. The present method time response results are compared with the numerical solution of Reynolds equation and a good agreement is recorded.