Vpliv zaostalih napetosti na obnašanje ojačanih ukrivljenih pločevin : magistrsko delo

Gomboši, Jana (author), Može, Primož (mentor), Piculin, Sara (comentor)

Magistrska naloga obravnava vpliv zaostalih napetosti na obnašanje ojačanih ukrivljenih panelov. Ti se vse pogosteje uporabljajo kot spodnja pasnica škatlastega prereza pri premostitvenih objektih daljših razponov. Zaostale napetosti se v konstrukciji razvijejo zaradi različnih procesov obdelave jeklenih elementov, kjer le-te ostanejo v materialu kot posledica plastičnih deformacij in neenakomernega ohlajanja materiala. Pri vitkih varjenih jeklenih konstrukcijskih elementih prisotnost geometrijskih nepopolnosti in zaostalih napetosti bistveno vpliva na izbočenje tlačenih delov in zmanjša njihovo nosilnost. Vpliv zaostalih napetosti na nosilnost je za ravne jeklene pločevine ustrezno zajet v standardu SIST EN 1993-1-5. Ker na področju ukrivljenih pločevin ni ustreznih navodil, se morajo projektanti za določanje mejne nosilnosti takšnih konstrukcij posluževati naprednih orodij za numerično analizo. Da bi ugotovili vpliv zaostalih napetosti na obnašanje ukrivljenih pločevin, je bila izvedena obsežna parametrična študija z upoštevanjem različnih geometrijskih karakteristik. Študija je bila izvedena na numeričnem modelu v programu Abaqus z upoštevanjem geometrijskih in materialnih nepopolnosti. Rezultati so bili primerjani z obstoječimi priporočili iz standarda SIST EN 1993-1-5 za ravne pločevine.

• Language: Slovenian
• Keywords: jeklene konstrukcije, škatlasti nosilec, ojačane ukrivljene pločevine, zaostale napetosti, geometrijske nepopolnosti, nosilnost
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Publisher: [J. Gomboši]
• Year: 2018
• PID: 20.500.12556/RUL-105292
• UDC: 624.014.2(043.3)
• COBISS.SI-ID: 8619105
• Publication date in RUL: 21.11.2018

GOMBOŠI, Jana, 2018, Vpliv zaostalih napetosti na obnašanje ojačanih ukrivljenih pločevin : magistrsko delo [online]. Master’s thesis. J. Gomboši. [Accessed 26 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=105292

Secondary language

• Language: English
• Title: Influence of Residual Stresses on the Behaviour of Stiffened Curved Panels : master thesis

Abstract

Master thesis deals with residual stresses and their influence on the behaviour of stiffened curved panels. The use of curved steel panels in bridge design has increased in the last twenty years due to their aesthetic and structural demands. Curved panels may be used as a transversally curved bottom flange of box girders. Due to their late application, there is lack of specifications in European standards, since they are neither flat nor fully cylindrical. Shell structures are highly sensitive to imperfections (geometric imperfections and residual stresses) and should be properly taken into account. According to EN 1993-1-5, which deals with flat panels, both types of imperfections may be replaced with so-called equivalent geometric imperfections. Considering that there are no design recommendations for curved panels, a large parametric study was performed in order to investigate the effect of residual stresses on the behavior of stiffened curved panels, together with other important geometric parameters, such as curvature, aspect ratio and plate slenderness. Firstly, a linear buckling analysis (LBA) was performed in order to get buckling modes that were later used as geometric imperfections in the nonlinear analysis (GMNIA). All numerical simulations were carried out using the finite element analysis software Abaqus. Finally, results were compared with existing requirements from standard EN 1993-1-5.

• Keywords: steel structures, box girder, stiffened curved panels, residual stresses, geometric imperfections, ultimate strength