- If a flexible rotor contacts its stator, the nonlinearities induced by
contact may result in a great variety of vibration phenomena. This article
presents experimental results gained at test rigs. Fundamental phenomena are
analyzed and discussed. First, a modular kit for rotordynamic experiments is
described. The kit allows customizing the properties of rotor and stator that
are relevant for the dynamic behavior. The system allows to specify target
values for natural frequencies, modal damping, clearance width, contact fric-
tion and others. Basic con� gurations based on this kit were used to study the
in
uence of mass, sti� ness and damping of both rotor and stator, contact fric-
tion and misalignment of the stator on the vibration of the rotor-stator system.
Extensions of the kit allowed the experimental investigation of systems with
a multitude of natural frequencies, highly
exible stators and even drop down
and overload incidents of rotors supported by active magnetic bearings. The
article also analyzes and explains the various vibration phenomena resulting
from contact. In particular, resonance diagrams from run-up and run-down
processes, orbit plots and frequency spectra are utilized to discuss the dynamic
characteristics. The motion types encountered include not only rotor syn-
chronous motions, but also multi frequency motions (forward and backward
whirl), sub- and super-harmonic motions, motions including sidebands as well
as chaotic motions. Emphasis is put on sensitive system parameters and on
existence and stability of the various types of motion.