title: Design optimization of rotating bodies
creator: Strauß, Frank
subject: ddc-510
subject: 510 Mathematics
description: The presented work focuses on design optimization problems for a general class of rotating bodies with different kinds of support. The rotation of rigid bodies causes vibrations which can lead to undesired noise and to a damage of the rotor. Therefore, the target of the optimization is to change the design of the rotor such that certain resonance frequencies are avoided in the operating speed range and the amplitude in the resonance case is reduced. Based on a suitable physical model, which includes the important effects of rotary inertia and gyroscopic moments, the equation of motion for the continuous rotor is obtained. The solution of this equation leads to a generalized eigenvalue problem. The resulting natural frequencies and eigenmodes are target values of our optimization. The corresponding operators are non-symmetric due to the presence of the gyroscopic terms. Using suitable boundary conditions the compactness of the operator can be shown which is used to prove the solvability of the eigenvalue problem. The existence of solutions of the optimization problem follows. For the numerical solution of the problem a discretization, based on a  variational formulation, is introduced. We prove that the solutions of the discretized optimization problem converge towards the solution of the  continuous optimization problem if the discretization parameter tends to zero. The discretized optimization problem is numerically solved by an iterative  optimization process and the application of different algorithms of the class of sequential convex programming. A mode tracking procedure to follow the modes of interest is considered. Moreover, ideas are presented, how a nonempty set of solutions can be achieved by multiobjective optimization approaches. Computational results for two different turbocharger models are shown which are supported either by linear spring and damper or nonlinear fluid-film bearings.  A significant reduction of mass of the rotor and of the amplitudes of the target modes is achieved in the considered cases. Further improvements are obtained by changes in the bearing configuration. All in all, the design optimization process for the rotating bodies leads to a reduction of noise and fatigue of material and an increase of efficiency.
date: 2005
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/5979/1/frank_strauss_diss.pdf
identifier: DOI:10.11588/heidok.00005979
identifier: urn:nbn:de:bsz:16-opus-59798
identifier:   Strauß, Frank  (2005) Design optimization of rotating bodies.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/5979/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng