Doctor's Theses (authored and supervised):

P. Helnwein:
"Zur initialen Abschätzbarkeit von Stabilitätsgrenzen auf nicht linearen Last-Verschiebungspfaden elastischer Strukturen mittels der Methde der Finiten Elemente";
Supervisor, Reviewer: H.A. Mang, H. Troger; Institute for Strength of Materials, Vienna University of Technology, 1996.

English abstract:
Frequently, loss of stability is the reason for the failure of thin-walled structures. A fully nonlinear prebuckling analysis for the mere purpose of obtaining the stability limit usually is too expensive for most problems in the field of civil and mechanical engineering. In order to reduce the necessary computational effort, estimations for the stability limit, based on the solution of linear eigenvalue problems, are frequently used.

The present book contains a comprehensive review of such kind of estimations for stability limits as well as the presentation of a so-called consistently linearized eigenproblem. The latter appears to be the best linear approximation of the stability condition based on an underlying geometrically nonlinear theory. In order to reduce the observed estimation errors, higher-order estimates are developed. As a consequence of the obtained significant reduction of these errors, particularly related to snap-through behavior, a nonlinear analysis can be avoided for a wide variety of engineering structures.

Concerning the results obtained by conventional estimation strategies, the increased accuracy of the higher-order estimates is demonstrated for different technical problems, including plane beams, spatial frames and shells. Finally, remarks on the feasibility of such an approach are given.

Keywords: stability, large displacements, @dissertation, Stabilität, begleitende Eigenwertanalyse, accompanying eigenvalue analysis, Abschaetzung, Abschätzbarkeit, Nichtlinearitaet, Schalen, elastische Strukturen, große Verschiebungen, initial, konsistently linearized eigenval, shell structures

Created from the Publication Database of the Vienna University of Technology.