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Prediction of random vibration using spectral methods
KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
2003 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

Much of the vibration in fast moving vehicles is caused bydistributed random excitation, such as turbulent flow and roadroughness. Piping systems transporting fast flowing fluid isanother example, where distributed random excitation will causeunwanted vibration. In order to reduce these vibrations andalso the noise they cause, it is important to have accurate andcomputationally efficient prediction methods available.

The aim of this thesis is to present such a method. Thefirst step towards this end was to extend an existing spectralfinite element method (SFEM) to handle excitation of planetravelling pressure waves. Once the elementary response tothese waves is known, the response to arbitrary homogeneousrandom excitation can be found.

One example of random excitation is turbulent boundary layer(TBL) excitation. From measurements a new modified Chase modelwas developed that allowed for a satisfactory prediction ofboth the measured wall pressure field and the vibrationresponse of a turbulence excited plate. In order to model morecomplicated structures, a new spectral super element method(SSEM) was formulated. It is based on a waveguide formulation,handles all kinds of boundaries and its elements are easily putinto an assembly with conventional finite elements.

Finally, the work to model fluid-structure interaction withanother wave based method is presented. Similar to the previousmethods it seems to be computationally more efficient thanconventional finite elements.

Place, publisher, year, edition, pages
Stockholm: Farkost och flyg , 2003. , 29, vi p.
Trita-AVE, ISSN 1651-7660 ; 2003:30
Keyword [en]
Spectral finite element method, distributed excitation, turbulent boundary layer measurements, random vibration, spectral super element method, wave expansion difference scheme, fluid-structure interaction
URN: urn:nbn:se:kth:diva-3694ISBN: 91-7283-678-4OAI: diva2:9532
Public defence
NR 20140805Available from: 2004-02-03 Created: 2004-02-03Bibliographically approved

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