Investigation on the dynamic behaviors of a rod fastening rotor based on an analytical solution of the oil film force of the supporting bearing

Abstract

The dynamic characteristics of rod fastening rotor supported by a finite journal bearing are investigated in this study. To model the dynamic behaviors of the bearing-rotor system, the oil film force of bearing is calculated by approximately solving the Reynolds equation with the variables separation method and Sturm–Liouville theory, and then a motion equation is developed with consideration of the contact and gyro effects of the disks of the rotor. To solve the motion equation with small error and excellent stability, an improved Newmark method is proposed. On this basis, the dynamics characteristics of the rod fastening rotor are analyzed for different rotor speeds, disk eccentricities, shaft bearing stiffness, and contact stiffness. And the orbits of the rod fastening rotor and integral rotor are compared. The numerical results indicate that the analytical solution of the oil film force has higher computational efficiency than the finite difference method. The rod fastening rotor shows higher stability than the integral rotor, and exhibits rich dynamic behaviors, such as periodic, qusi-periodic, period-2, period-4, and period-6.