NON-LINEAR BEARING STIFFNESS PARAMETER EXTRACTION FROM RANDOM RESPONSE IN FLEXIBLE ROTOR-BEARING SYSTEMS

✍ Scribed by R. Tiwari; N.S. Vyas

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 408 KB
• Volume: 203
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.1996.0786

✦ Synopsis

A procedure for estimation of non-linear stiffness parameters of rolling element bearings supporting a flexible rotor, based on analysis of the random response signals picked up from the bearing caps, is developed. The non-linear multi-degree-of-freedom equations, governing the motion of a flexible shaft carrying a disc and experiencing random excitations due to imperfections of the bearing surfaces and assembly, are subjected to co-ordinate transformation and subsequently modelled as multi-dimensional Markov process through the Fokker-Planck equation. The solution procedure for the Fokker-Planck equation and the assumptions involved are outlined. The vibrations experienced at the bearings are processed through a curve fitting algorithm to obtain the necessary bearing stiffness parameters. The technique has an advantage over other existing ones in that it does not require an estimate of the excitation forces and measurements of vibrations at the rotor disc and works directly on the response signals from the bearing caps. The algorithm is illustrated for a laboratory rotor-bearing test rig and the result are compared with those obtained through an existing analytical model. The developed algorithm is tested by numerical simulation.