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|Title:||DYNAMIC ANALYSIS OF OIL LUBRICATED LOBED BEARINGS MOUNTED ON FLEXIBLE DAMPED PEDESTALS|
|Authors:||Madhok, V. K.|
|Keywords:||MECHANICAL & INDUSTRIAL ENGINEERING|
|Abstract:||The usual analyses of the dynamic characteristics of the rotor systems supported on fluid film bearings have been based on the assumption of rigid pedestals of the bearings. However, some investigations have reported the pedestal flexibility and damping to be very Influential parameters of the bearing dynamic characteristics,., It has been reported that with proper design of the bearing pedestals via— a— via flexibility and damping, the stability margin of the journal bearing systems can be substantially raised over the corresponding rigid pedestal case stability margin,, This thesis undertakes the dynamic analyses of oil lubricated lobed journal bearings supported on flexible damped pedestals, Lobed bearings are known to possess superior dynamic characteristics, and are, therefore, extensively used in high speed machinery where the usual plane ,journal bearings cannot be used, However, with increasing speeds of the rotating machinery, efforts are on going to develop bearings superior to the lobed bearings themselves. Quite many antiwhir j and tilting pad bearings are in fact variations of the lobed bearings. Although such variations result in usually only marginal improvement In the dynamic characteristics, On the other hand, with a proper design of bearing pedestals# as shown In some analytical investigations.., manifold increase in the stability margins can be achieved over the stability margins of the rigid pedestal bearing. This feature has, in fact, been the motivation behind this work. The lobed bearing configurations taken up for the study are elliptical, offset— halv:s, three— lobe and four—lobe bearings. The results bring out clearly the salient features of the effect of pedestal parameters on the stability .margin of lobed journal bearing systems. The results include some representative nonlinee- response plots of the disvrbod motion of the journal center taking the operating point in the stable and unstable regions of the linearized journal bearing system* These results authenticate the numerical approach used in establishing the stability margin of the bearing systems with damped flexible pedestals.|
|Appears in Collections:||DOCTORAL THESES (MIED)|
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