Strategies for finite element eigenvalue analysis of structures enclosing fluids

Daniel, William John Trevor (1979). Strategies for finite element eigenvalue analysis of structures enclosing fluids PhD Thesis, School of Engineering, The University of Queensland. doi:10.14264/uql.2014.490

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Author Daniel, William John Trevor
Thesis Title Strategies for finite element eigenvalue analysis of structures enclosing fluids
School, Centre or Institute School of Engineering
Institution The University of Queensland
DOI 10.14264/uql.2014.490
Publication date 1979
Thesis type PhD Thesis
Supervisor R. J. Hooker
Total pages 181
Language eng
Subjects 091504 Fluidisation and Fluid Mechanics
020303 Fluid Physics
Formatted abstract
This study of the steady state vibration of structures enclosing fluids was motivated by the problem of predicting the natural frequencies of large electric power transformers. The finite element method was chosen as a suitably flexible computational approach to such problems, but the modelling experience gained early in the project emphasised the need to achieve an efficient computation strategy in order to reduce the expense of obtaining solutions for realistic models. This modelling work is detailed in chapter 7.

The bulk of this thesis is therefore devoted to means of reducing the computation needed to solve fluid-structure finite element eigenvalue problems. Three approaches have been studied.
(1) Chapter 3 contains an investigation of the use of two different orders of interpolation to produce an eigenvalue problem of reduced dimensions while preserving sufficient accuracy to describe modes of interest.
(2) In chapter 4 the exploitation of symmetry is considered. The symmetric geometry of a fluid cavity may be exploited even in the absence of symmetry in the mode shapes of the coupled structure-fluid system.
(3) "Modal synthesis" methods are presented in chapter 5. These enable symmetric modes of a submesh of the problem to be corrected to account for lack of symmetry in the complete models of the structure or the fluid. A closely related method enables a solution which assumes the enclosed fluid is incompressible to be corrected to account for the compressibility of the fluid.

In chapter 6 these methods are considered jointly and computational strategies using them are developed.
Keyword Electric transformers -- Vibration -- Mathematical models

Document type: Thesis
Collection: UQ Theses (RHD) - UQ staff and students only
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Created: Wed, 26 Nov 2014, 11:01:50 EST by Mary-Anne Marrington on behalf of Scholarly Communication and Digitisation Service