Multistage Blisk Large Mistuning Modeling Using Fourier Constraint Modes and Pristine Rogue Interface Modal Expansion
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Publisher:The Ohio State University
Series/Report no.:The Ohio State University. Department of Mechanical and Aerospace Engineering Undergraduate Research Theses; 2018
In the turbomachinery field, a great deal of research has focused on understanding the effects of mistuning on the dynamics of each stage. Mistuning in bladed disks is due to the blade to blade differences that typically occur due to manufacturing tolerances and in-service wear. Mistuning greatly complicates the modelling of bladed disks since it is inherently random and requires a statistical analysis to be conducted to understand the full dynamics of a bladed disk design. Moreover, mistuning destroys the cyclic symmetry of the bladed disk, which prevents cyclic analysis from being used to model the system. Cyclic analysis enables single sector models and calculations to be employed to analyze the full stage dynamics. A wide array of methods to efficiently (using single sector models and calculations) model the mistuning in these structures have been developed to account for small stiffness changes or geometric changes in the blades and even very large stiffness changes and geometric changes due to blends or dents. Typically, these analyses have been done on single stage models and have ignored the effects of the interaction of multistage and mistuning effects. Recently, a statistical analysis of small mistuning effects in multistage rotors has been conducted and shown the importance of multistage modeling . Additionally, a method to efficiently account for large mistuning in multistage rotors has recently been developed . The focus of this work is to better understand the combined effects of large and small mistuning on multistage rotors. The presentation will discuss how reduced order models of multistage rotors with both large and small mistuning can efficiently be created. It will also discuss the different effects of various types of large mistuning (e.g., dents, bends, blends) on the multistage dynamics.  K. D'Souza, and B. I. Epureanu, A Statistical Characterization of the Effects of Mistuning in Multistage Bladed Disks, ASME Journal of Engineering for Gas Turbines and Power, 134(1), Pages 1-8, 2012, DOI:10.1115/1.4004153.  E. Kurstak, and K. D'Souza, Multistage and Large Mistuning Modeling using Fourier Constraint Modes and PRIME, ASME Turbo Expo, Pages 1-13, Charlotte, NC, 2017.
Academic Major: Aeronautical and Astronautical Engineering