Analysis of nozzle flexibility in nozzle-vessel intersection in piping system

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Journal Title
Journal ISSN
Volume Title
School of Engineering | Master's thesis
Date
2013
Major/Subject
Lujuusoppi
Mcode
Kul-49
Degree programme
Language
en
Pages
x + 61 s. + liitt. 40
Series
Abstract
The goal of the work is to research the flexibility of the nozzle-vessel connection in pipeline system. In conventional methods of piping stress analysis nozzle-vessel juncture is assumed to be rigid. In reality, the juncture possesses the flexibility. Ignoring the nozzle flexibility in stress analysis leads to large overvaluation of the nozzle loads. State of art had been studied and evaluated. Modern state of research of nozzle flexibility had been performed primarily for the vessels not subjected to pressure. In this work comparison of different methods of flexibility calculation had been prepared. Existing piping system had been created and simulated in finite element method software. In code-based software most conservative assumption with vessel-nozzle junction and flanges fixed; with nozzle flexibility had been simulated. Finite element method model had been built and simulated with maximum flexible nozzles and another finite element method model with flange connection fixed. After comparison of the results had been established, that the FEM model of the system with nozzle-vessel junction free to move possesses highest flexibility with lowest nozzle reactions. Highest reactions had been obtained for the system with fixed nozzles and flanges. The results of work give the suggestion of utilizing the nozzle flexibilities in piping stress analysis in order to achieve higher accuracy of results.
Description
Supervisor
Marquis, Gary
Thesis advisor
Hämäläinen, Matti
Paldanius, Rikumatti
Lemetti, Sergei
Keywords
piping stress analysis, nozzle flexibility, nozzle stiffness
Other note
Citation