Dynamics IV - Rotor Systems (FSI-RRS)

The course aims to introduce students to the basics of rotor-dynamic systems and evaluate the critical speed of shafts and disks.

Students will acquire basic theoretical knowledge in the field of rotor systems and reduction of degrees of freedom and will become familiar with the possibilities of computational modeling. They will learn how to predict resonance states and critical speeds of rotating machines and how to suppress them. Students will be able to perform a reduction of systems with many degrees of freedom, thus reducing computational time.

Students must be able to solve the eigen value problem, solve the response in forced, steady and transient oscillations of systems with n degrees of freedom. Furthermore, the students must to have knowledge of the basics of nonlinear vibrations, and knowledge of the basics of experimental modal analysis. The student must know, matrix calculus, linear algebra, differential equations, fundamentals of the finite element method.

In the course, students learn about the basic dynamic properties and dynamic behavior of components and parts of rotating systems. In particular, shafts, blades, and disks of turbines and compressors. Attention is focused on rotor natural frequencies, mode shapes, and critical speed prediction. Some problems can be computationally challenging, especially when solved in the time domain. Therefore, students will be introduced to methods of reducing degrees of freedom.

Active participation in the course, obtaining at least 20 points (out of 40 possible), which can be received by completing tasks and achieving at least 30 points (out of 60 possible) in the test. The specific form of the tests, types, number of tasks or questions and details of the assessment will be given by the lecturer during the semester. The final evaluation is given by the sum of the pointsaccording ECTS. For successful completion of the course it is necessary to obtain at least 50 points.

• Introduction to rotor systems, basic models of rotors


• Undamped Laval (Jeffcott) rotor in rigid and flexible bearing supports


• Laval (Jeffcott) rotor with external and internal damping.


• Oscillation of undamped rotor with consideration of gyroscopic effects


• Vibration of bladed disks, Campbell diagram


• Rotor balancing


• Methods of reduction of dynamic systems

• Calculation of critical speeds using simple rotor models


• Simulation of electric motor start-up in the time domain


• Simulation of rotor behaviour in bearings


• Vibration of disks and bladed disks


• Modeling of bladed disks using cyclic symmetry


• Degrees of freedom reduction: Examples in MATLAB, MSC Adams and ANSYS