Bauhaus Summer School in Forecast Engineering: From Past Design to Future Decisions 21 August – 1 September 2017, Weimar, Germany Numerical Analyses on the Stability of Beam-Columns COBZARU, Stefan Technical University of Civil Engineering of Bucharest IBRAHIM, Mohamed Ain Shams University JAKAB, Dominiq Politehnica University of Timisoara KARABULUT, Burak KU Leuven VELA, Silvia University of Genoa Abstract Stability of beam-columns is of paramount importance since vulnerability to instability problems is most of the time the governing design criterion for steel structural systems. The comparison between Eurocodes (EN 1993-1-1 2006) and German DIN standards (DIN 18800-1 2008) for evaluating the lateral torsional behaviour of beam elements has been a controversial discussion over the last decades. Especially, calculation of critical moment value (Mcr) differs remarkably between Non-Contradictory Complementary Contribution (NCCI) documents referring to recent editions of Eurocodes and former applications in German practice (Bureau and Galea 2005, DIN 18800-2 2008). In order to bring enlightenment to this topic, a comparative analytical study has been performed. As a part of this contribution, an experimental test has also been designed to investigate the different failure modes associated with the beam elements as a result of bending about strong and weak axes. The experimental part has been furthermore extended with numerical analyses performed by ANSYS finite element (FE) solver (ANSYS Inc. 16.2 2015). Moreover, a parametric study investigating the influencing parameters such as geometric properties of the cross-sections, length of the beam element, load application point and so forth was conducted. Introduction A necessary condition that structures must satisfy in order to meet the performance requirements is equilibrium. Equilibrium is defined as “stable” when the system returns to its initial state after a small perturbation. Equilibrium is defined as “unstable”, when the system cannot return into its initial condition after a perturbation and cannot reach another equilibrium configuration. It is defined as indifferent when the system finds a new equilibrium condition after a perturbation. Instability of structural members must be taken into account for the design of structural members, especially when dealing with steel structures. Instability reduces the capacity of the steel structures by hindering the plastification of the cross sections. Problems associated with instability may be either global or local. Global instability occurs when the entire element is involved, while local instability occurs within the parts of cross sections, involving
13
Embed
Numerical Analyses on the Stability of Beam-Columns
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Bauhaus Summer School in Forecast Engineering: From Past Design to Future Decisions
21 August – 1 September 2017, Weimar, Germany
Numerical Analyses on the Stability of Beam-Columns
COBZARU, Stefan
Technical University of Civil Engineering of Bucharest
IBRAHIM, Mohamed
Ain Shams University
JAKAB, Dominiq
Politehnica University of Timisoara
KARABULUT, Burak
KU Leuven
VELA, Silvia
University of Genoa
Abstract
Stability of beam-columns is of paramount importance since vulnerability to instability problems is
most of the time the governing design criterion for steel structural systems. The comparison between
Eurocodes (EN 1993-1-1 2006) and German DIN standards (DIN 18800-1 2008) for evaluating the
lateral torsional behaviour of beam elements has been a controversial discussion over the last decades.
Especially, calculation of critical moment value (Mcr) differs remarkably between Non-Contradictory
Complementary Contribution (NCCI) documents referring to recent editions of Eurocodes and former
applications in German practice (Bureau and Galea 2005, DIN 18800-2 2008). In order to bring
enlightenment to this topic, a comparative analytical study has been performed. As a part of this
contribution, an experimental test has also been designed to investigate the different failure modes
associated with the beam elements as a result of bending about strong and weak axes. The
experimental part has been furthermore extended with numerical analyses performed by ANSYS finite
element (FE) solver (ANSYS Inc. 16.2 2015). Moreover, a parametric study investigating the
influencing parameters such as geometric properties of the cross-sections, length of the beam element,
load application point and so forth was conducted.
Introduction
A necessary condition that structures must satisfy in order to meet the performance requirements is
equilibrium. Equilibrium is defined as “stable” when the system returns to its initial state after a small
perturbation. Equilibrium is defined as “unstable”, when the system cannot return into its initial
condition after a perturbation and cannot reach another equilibrium configuration. It is defined as
indifferent when the system finds a new equilibrium condition after a perturbation.
Instability of structural members must be taken into account for the design of structural members,
especially when dealing with steel structures. Instability reduces the capacity of the steel structures by
hindering the plastification of the cross sections.
Problems associated with instability may be either global or local. Global instability occurs when the
entire element is involved, while local instability occurs within the parts of cross sections, involving