Three-Dimensional Rotordynamic Finite-Element Formulations
Loading...
URL
Journal Title
Journal ISSN
Volume Title
School of Electrical Engineering |
D4 Julkaistu kehittämis- tai tutkimusraportti tai -selvitys
Unless otherwise stated, all rights belong to the author. You may download, display and print this publication for Your own personal use. Commercial use is prohibited.
Authors
Date
2020
Major/Subject
Mcode
Degree programme
Language
en
Pages
200
Series
Aalto University publication series SCIENCE + TECHNOLOGY, 5/2020
Abstract
Work presents detailed derivations of various three-dimensional rotordynamic formulations. The equation of motion is derived by two approaches; using Lagrange's equation and using Galerkin's method. It is shown that these approaches give the same equation of motion. Thorough treatment of the relevant kinematics is presented. Nonlinear strain and stress measures are adopted to create formulation, which is valid for large displacements and material rotations, but for small strain levels. Therefore, the resulting equation of motion is nonlinear. This nonlinear equation of motion is linearized yielding a model, which is valid for large equilibrium displacements and small deviations around the equilibrium. In addition, a linearized model, which assumes constant equilibrium displacements, is presented. After the form of the energy expressions and equation of motion are obtained in a generic case, the work presents the implementation details associated with solid element model, cyclic symmetric model and axisymmetric model and how different types of submodels can be combined. In addition, publication presents modal reduction utilizing the symmetry properties present in the axisymmetric model, cyclic model and combined model consisting of axisymmetric and cyclic sub-models. Work contains four simple example cases, which present comparisons to literature and explorethe model validity ranges of different approaches.Description
Keywords
Rotordynamics, Finite elements