Simulation of geometrical imperfections and reliability estimation of cylindrical shell structures
Translated title
Simulering af geometriske imperfektioner og pålidelighedsestimering af cylindriske skalkonstruktioner
Authors
Boserup, Martin Winther ; Krog, Christian Lebech
Term
4. term
Education
Publication year
2014
Submitted on
2014-06-10
Pages
80
Abstract
Denne afhandling undersøger knækning – et pludseligt tab af stabilitet – i tyndvæggede cylindriske stålcylindre under aksial tryk. Gennem en state-of-the-art-gennemgang vises det, at selv små geometriske imperfektioner markant reducerer den kritiske knækmodstand i forhold til en perfekt cylinder. Derfor analyseres tre forskellige imperfektionsmønstre ved hjælp af den mest komplekse af de anbefalede procedurer i Eurocode: geometrisk og materielt ikke-lineær analyse med imperfektion (GMNIA). Afhandlingen vurderer desuden pålideligheden af de uperfekte numeriske modeller og af de semiempriske modeller i Eurocode og DNV, og kalibrerer delkoefficienter til brug sammen med disse.
This thesis investigates buckling—an abrupt loss of stability—in thin-walled cylindrical steel shells under axial compression. A state-of-the-art review shows that even small geometric imperfections substantially reduce the critical buckling resistance compared with a perfect cylinder. To address this, three different imperfection patterns are analyzed using the most complex of the recommended Eurocode procedures: geometrically and materially non-linear analysis with imperfection (GMNIA). The study also estimates the reliability of the imperfect numerical models and of the semi-empirical models in Eurocode and DNV, and calibrates partial coefficients for use with them.
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