TECHNICAL PAPERS: Gas Turbines: Structures and Dynamics

Identification of Frequency-Dependent Parameters in a Flexible Rotor System

[+] Author and Article Information
Qingyu Wang1

Department of Mechanical and Aerospace Engineering, University of Virginia, ROMAC Laboratories, 122 Engineer’s Way, Charlottesville, VA 22904qw4k@virginia.edu

Eric H. Maslen

Department of Mechanical and Aerospace Engineering, University of Virginia, ROMAC Laboratories, 122 Engineer’s Way, Charlottesville, VA 22904ehm7s@virginia.edu


Corresponding author.

J. Eng. Gas Turbines Power 128(3), 670-676 (Sep 28, 2005) (7 pages) doi:10.1115/1.2135814 History: Received August 25, 2005; Revised September 28, 2005

In a rotor-bearing system, there are usually some under- or unmodeled dynamic components that are considered frequency dependent, such as foundations, bearings, and seals. This paper presents a method to identify the dynamic behavior of these components using an otherwise accurate engineering model of the system in combination with available measurements of system frequency response functions. The approach permits treatment of flexible rotors and allows that the system test excitations and measurement sensors are not collocated. Because all engineering models contain some residual error and all measurements incorporate an element of noise or uncertainty, the quality of the identified parameters must be estimated. This paper introduces application of μ analysis to solve this problem, resulting in acceptable solution time and hard guarantees of solution reliability. Two illustrative examples are provided, showing that the presented approach is an efficient method to identify and bound these parameters.

Copyright © 2006 by American Society of Mechanical Engineers
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Figure 1

Identification processes: upper route is parametric updating, lower route is nonparametric updating

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Figure 2

Analysis Framework

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Figure 3

Uncertainty cloud and bounds

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Figure 4

Simplified rotor-bearing-foundation system

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Figure 5

Uncertainty bound

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Figure 6

Normalized uncertainty upper bounds

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Figure 7

Uncertainty bounds for ω=37.25rad∕s, where – outer bound of MU, - - inner bound of MU, - · - NM

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Figure 9

Excitations and sensors diagram

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Figure 10

Identification with bounds for 1% error

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Figure 11

Identification with bounds for 4% error



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