Nonlinear Dynamic Response And Stability Analysis Of Rotor-bearing Systems With Samcef/rotor

Rotating machine plays a very important role in transport, power, machinery, aerospace technology and so on. It is also one of the main equipments in national economy. Along with the rapid development of production,science and technology, researches on some problems of nonlinear dynamical behaviors of rotor systems have evolved to be a top point in related fields.In this paper, with the finite element analysis software Samcef/Rotor, the nonlinear behavior of the single span symmetric rotor-bearing system and double-span rotor-bearing system were calculated respectively. The movements of the rotors were characterized by time history diagrams, orbits, phase plots, Poincare maps and spectrum diagrams. The major work and conclusions of the thesis are as follows:1.The state of nonlinear dynamics of rotor-bearing systems was summarized;2.With the software Samcef/Rotor, the FE model of a single-span symmetric rotor-bearing system was established. Phase diagrams, Poincare maps, time history curves , orbits, and the bifurcation diagrams were obtained based on the FE model. The results showed that: with the rotary speed changing, the system presents different types of dynamic behaviors as the pattern of: periodic motion, quasi-periodic motion and periodic motion;3.The FE model of a double-span rotor-bearing system model was established using Samsef/Rotor, and characteristic figures such as phase diagrams of the rotor movement, Poincare maps, time history curves, orbits, and the bifurcation diagram at different speed were obtained. The results showed that: with the speed changing, system is with complex dynamic behaviors of: periodic motion and quasi-periodic motion;4.The influence of average thickness of the bearing oil film, bearing width and the phase angle between the mass centers of different disks on the movements of the rotors were analyzed. The results show that with the film thickness increasing, the system stability decreases;The results of the thesis would be helpful to understand the instability mechanism of the rotor-bearing systems with the nonlinear oil film forces.