Item Details

Influence of Frequency Dependent Flexible Bearing Supports on Rotor Stability

Wygant, Karl David
Format
Thesis/Dissertation; Online
Author
Wygant, Karl David
Advisor
Barrett, Lloyd
Knospe, Carl
Morton, Harold
Abstract
A common method for performing stability analyses of turbomachinery is the linear transfer matrix method. A serious limitation of the transfer matrix method is an inability to adequately handle branched systems. A system is considered branched when the differential equation describing an element is not strictly dependent on two adjacent elements. Two byproducts of branching are singularities and rotor-bearing cross talk. Singularities are the result of exact dynamic reduction, a method used to incorporate additional degrees of freedom into the rotor model. Singularities, points in the complex plane which approach infinity, bias the gradient descent search methods used to find system eigenvalues. Rotor cross talks, coupling between bearings through a flexible casing, create a dependence on unknown rotor states. The transfer matrix method breaks down due to numerical convergence problems associated with singularities in the eigenvalue search space and dependence on unknown rotor states. Methods of eliminating these problems are introduced and demonstrated to be effective through typical industrial examples.

Note: Abstract extracted from PDF file via OCR.

Language
English
Date Received
20170914
Published
University of Virginia, Department of Engineering, MS (Master of Science), 1993
Published Date
1993
Degree
MS (Master of Science)
Collection
Libra ETD Repository
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