Numerical investigation with rub-related vibration in rotating machinery

Nonlinear behavior of rub-related vibration in rotating machinery is studied with a large number of numerical simulations. A simplified model is used to capture the dynamic response of the rotor when it rubs its housing. It is shown that the model displays rich dynamics, many of which are rather complicated and cannot be captured with linear models. The effects of rotating speed, clearance, damping coefficient, friction coefficient, and boundary stiffness are investigated. The data generated are displayed graphically and explained with the aid of the theory of modem nonlinear dynamics. It is demonstrated that the system goes through an extraordinary route to chaos and that the stretching, contraction, and folding of initial volumes may indicate the existence of a horseshoe map, which plays an important role in creating chaotic phenomena. These results help engineers to optimize the design of rotating machinery, as well as to develop sensitive monitoring/diagnosis systems assessing machinery conditions.