Document Details Document Type : Article In Journal  Document Title : Start-up Dynamic Analysis of a Rotor Supported by Fluid Film Bearings التحليل الديناميكي لعمود محمول على حوامل منزلقة   Subject : Mechanical Engineering  Document Language : English  Abstract : Start-up and steady state dynamics of a rotor supported by fluid film bearings is studied. A rotor is assumed as a thin disk located on the middle of an elastic shaft, which is supported by fluid film bearings. The journal bearing is selected as a short-plain type and it is represented by direct and cross-coupling stiffness and damping coefficients, which are angular speed dependent. An electric motor accelerates the rotor and its speed is controlled by a second order transfer function. Simulation results show that for a certain angular speed range the system becomes unstable. The instability region has lower and upper limits. The journal bearings affect the rotor, the equivalent damping ratios and the natural frequencies in x and y directions differ and cause 2x-critical speed super-harmonic oscillations. Before the lower limit of the unstable region, the journal whirl speed is equal to one-half of the rotor angular speed and the equivalent natural frequencies of the rotor in x and y directions are equal to the critical speed. After the upper limit of the unstable region, the journal whirl speed is always equal to the critical speed and one of the equivalent natural frequencies of the rotor becomes one-half of the rotor angular speed. In this region high amplitude 2x-critical speed super-harmonic oscillations appear  ISSN : 1741-2986  Journal Name : Journal of Vibration and Control  Volume : 16  Issue Number : 6  Publishing Year : 1431 AH 2010 AD  Article Type : Article  Added Date : Wednesday, April 6, 2011  Researchers Researcher Name (Arabic) Researcher Name (English) Researcher Type Dr Grade Email خالد عبدالله النفيعي Alnefaie, Khaled Abdullah Researcher Doctorate kalnefaie@kau.edu.sa Files File Name Type Description  29579.pdf pdf Start-up Dynamic Analysis of a Rotor Supported by Fluid Film Bearings Back To Researches Page