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A nonlinear model for rotor‐shaft joints of high speed rotor systems with internal damping
Author(s) -
Fischer Jonas,
Strackeljan Jens
Publication year - 2008
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.200810371
Subject(s) - rotor (electric) , nonlinear system , stiffness , control theory (sociology) , critical speed , bilinear interpolation , physics , mechanics , engineering , structural engineering , mathematics , computer science , statistics , control (management) , quantum mechanics , artificial intelligence
Viscous internal damping in joints of high speed rotor systems causes instabilities above a certain frequency of revolution. In the majority of cases a nonlinearity adjusts the stability margin towards higher frequencies. In this paper an analytical solution of a nonlinear four degrees of freedom rotor model with internal damping is proposed, which enables to clearly analyse the influence of shaft stiffness, connection stiffness, rotor mass and shaft mass. The steady state solution of the unbalance case and the stability boundaries are deduced analytically. The stabilizing effect of the nonlinearity is shown. The analytical solutions are in good agreement with numerical results obtained by FERAN, a rotor dynamic simulation tool. A model, representing the rotor–shaft connection with an o–ring has been analyzed by a hydro pulse rig. Beneath the linear way, two further approaches to describe the measured hysteresis, a cubic and a bilinear force law are shown in the paper. The different analytical and numerical results for the whole rotor system with these three approaches are compared. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)