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Academic Blade Geometries for Baseline Comparisons of Forced Vibration Response Predictions

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Date Issued:
2017
Abstract/Description:
Predicting the damping associated with underplatform dampers remains a challenge in turbomachineryblade and friction damper design. Turbomachinery blade forced response analysismethods usually rely on nonlinear codes and reduced order models to predict vibration characteristicsof blades. Two academic blade geometries coupled with underplatform dampers are presentedhere for comparison of these model reduction and forced response simulation techniques. The twoblades are representative of free-standing turbine blades and exhibit qualitatively similar behavioras highly-complex industrial blades. This thesis fully describes the proposed academic bladegeometries and models; it further analyzes and predicts the blades forced response characteristicsusing the same procedure as industry blades. This analysis classifies the results in terms of resonancefrequency, vibration amplitude, and damping over a range of aerodynamic excitation toexamine the vibration behavior of the blade/damper system. Additionally, the analysis investigatesthe effect variations of the contact parameters (friction coefficient, damper / platform roughnessand damper mass) have on the predicted blade vibration characteristics, with sensitivities to each parameter. Finally, an investigation of the number of modes retained in the reduced order modelshows convergence behavior as well as providing additional data for comparison with alternativemodel reduction and forced response prediction methods. The academic blade models are shownto behave qualitatively similar to high fidelity industry blade models when the number of retained modes in a modal analysis are varied and behave qualitatively similar under sensitives to designparameters.
Title: Academic Blade Geometries for Baseline Comparisons of Forced Vibration Response Predictions.
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Name(s): Little, James, Author
Kauffman, Jeffrey, Committee Chair
Gordon, Ali, Committee Member
Bai, Yuanli, Committee Member
University of Central Florida, Degree Grantor
Type of Resource: text
Date Issued: 2017
Publisher: University of Central Florida
Language(s): English
Abstract/Description: Predicting the damping associated with underplatform dampers remains a challenge in turbomachineryblade and friction damper design. Turbomachinery blade forced response analysismethods usually rely on nonlinear codes and reduced order models to predict vibration characteristicsof blades. Two academic blade geometries coupled with underplatform dampers are presentedhere for comparison of these model reduction and forced response simulation techniques. The twoblades are representative of free-standing turbine blades and exhibit qualitatively similar behavioras highly-complex industrial blades. This thesis fully describes the proposed academic bladegeometries and models; it further analyzes and predicts the blades forced response characteristicsusing the same procedure as industry blades. This analysis classifies the results in terms of resonancefrequency, vibration amplitude, and damping over a range of aerodynamic excitation toexamine the vibration behavior of the blade/damper system. Additionally, the analysis investigatesthe effect variations of the contact parameters (friction coefficient, damper / platform roughnessand damper mass) have on the predicted blade vibration characteristics, with sensitivities to each parameter. Finally, an investigation of the number of modes retained in the reduced order modelshows convergence behavior as well as providing additional data for comparison with alternativemodel reduction and forced response prediction methods. The academic blade models are shownto behave qualitatively similar to high fidelity industry blade models when the number of retained modes in a modal analysis are varied and behave qualitatively similar under sensitives to designparameters.
Identifier: CFE0006616 (IID), ucf:51281 (fedora)
Note(s): 2017-05-01
M.S.M.E.
Engineering and Computer Science, Mechanical and Aerospace Engineering
Masters
This record was generated from author submitted information.
Subject(s): Friction damping -- Turbine blade -- underplatform damper -- model reduction -- forced vibration response
Persistent Link to This Record: http://purl.flvc.org/ucf/fd/CFE0006616
Restrictions on Access: public 2017-05-15
Host Institution: UCF

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