Title page for ETD etd-12012000-175109


Type of Document Master's Thesis
Author Iglesias, Angel Moises
URN etd-12012000-175109
Title Investigating Various Modal Analysis Extraction Techniques to Estimate Damping Ratio
Degree Master of Science
Department Mechanical Engineering
Advisory Committee
Advisor Name Title
Wicks, Alfred L. Committee Chair
Burdisso, Ricardo A. Committee Member
Mitchell, Larry D. Committee Member
Keywords
  • Damping Ratio
  • Dynamic Properties
  • Vibrations
Date of Defense 2000-06-29
Availability unrestricted
Abstract
Many researchers have devoted their work to the development of modal analysis extraction techniques in order to obtain more reliable identification of the modal parameters. Also, as a consequence of all this work, there are some other works devoted to the evaluation and comparison of these methods in order to find which one is the most reliable method with respect to certain characteristics. In this thesis the Rational Fraction Polynomial (RFP) Method, the Prony or Complex Exponential Method (CEM), the Ibrahim Time Domain (ITD) Method, and Hilbert Envelope Method are used to evaluate how the accuracy of the damping ratio is affected with respect to various parameters and conditions. The investigation focuses in the estimation of damping ratio because among the modal parameters, it is the most difficult to model. Each method is evaluated individually in order to understand how the damping ratio estimation is affected with respect to each method when the characteristics of the FRF are changed. Also, they are compared to show that, in general, the Rational Fraction Polynomial Method is a more reliable method than the other methods. To investigate this, a simulated analytical data and an experimental data are processed to estimate the modal parameters, but focusing in the damping ratio. For the simulated analytical data the damping ratio's percent of error were calculated. The highest damping ratio's percent of error of the RFP was 0.0073501%. In the other hand, for the CEM, ITD, and Hilbert Envelope Method their highest damping ratio's percent of error were 83.02%, 99.82%, and 4.077%, respectively.

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