Equivalent unique global and local initial imperfection - Imperfection in EN 1993-1-1 and EN 1999-1-1 Clause 5.3.2 (11) - calculation procedure and discovered obstacles

Brodniansky, Ján

doi:10.1556/606.2017.12.3.4

Cited by 3 publications

(9 citation statements)

References 14 publications

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“…The paper [8] explains how to use Unique Global and Local Initial (UGLI) imperfection method. The PhD student [9] had problem to use this method for special non-uniform column in compression and therefore writes about obstacles of this method. In fact there are no obstacles in this method.…”

Section: Comparisons Of the Most Important Resultsmentioning

confidence: 99%

Investigation of metal built-up columns Part II: Results

Baláž

Koleková

Moroczová

et al. 2021

Pollack

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In the frame of a large parametrical study metal built-up columns made from steel and made of aluminum alloy were investigated. The second order theory is used for the analysis of the battened and laced built-up columns under combined compression and bending. The bottom column ends are fixed and the upper ones are free in the case of in-plane buckling. At the column base the translation and the rotation are fixed, at the column top the translation and the rotation are free in the case of in-plane buckling. Translation is fixed and rotation is free at both column ends in out-of plane buckling. The built-up columns are considered as the columns with effective bending and smeared shear stiffness with a local bow imperfection amplitude e0 = L/500.

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Section: Comparisons Of the Most Important Resultsmentioning

confidence: 99%

Investigation of metal built-up columns Part II: Results

Baláž

Koleková

Moroczová

et al. 2021

Pollack

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“…Brodniansky [24], another Ph.D. student from Bratislava, used a modified Dallemule's computer program and pointed out some numerical obstacles when calculating the location of the critical section x cr for the column with step change in cross-sectional parameters and step change in normal force along the members.…”

Section: Overview and Analysis Of Current Statementioning

confidence: 99%

“…Example 5 A Ph.D. student wrote in [24] about the obstacles of the method because he was not able to obtain the location of the critical section due to the never-ending cycle by going from finding the "critical section" to the other one and back. The fifth example shows that proposed method has no such problem.…”

Section: Application To the Case Where Problems Were Found To Obtain ...mentioning

confidence: 99%

Assessment of in-Plane Behavior of Metal Compressed Members with Equivalent Geometrical Imperfection

et al. 2020

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A new procedure was presented with the objective of proving that it is the generalization of current attempts in designing compressed members and structures which is able to solve cases where other authors have problems. It is the further development of the former methods published by Chladný, Baláž, Agüero et al., which are based on the shape of the elastic critical buckling mode of the structure. Chladný’s method was accepted by CEN/TC 250 working groups creating Eurocodes. Both current Eurocodes EN 1993-1-1:2005 and EN 1999-1-1:2007 in their clauses 5.3.2(11) enable applying the geometrical equivalent unique global and local initial (UGLI) imperfection. The imperfection has the shape of the elastic critical buckling mode with amplitude defined in 5.3.2(11). UGLI imperfection is an alternative to the global sway and local bow initial imperfections defined in 5.3.2(3) and to the imperfections described in the clause 5.3.2(6). The determination of the location and value of UGLI imperfection proved to be onerous by some authors, especially in cases of members with variable cross-sections or/and axial forces. The paper also provides for special cases a procedure to detect the critical cross-section along the member which is defined as the one in which the utilization factor obtains maximum values. The new approach is validated by the investigation of five complex structures made of steel and one made of aluminum alloy solved by other authors. Comparisons of the results with those of other authors and with the Geometrically and Materially Nonlinear Analysis with Imperfections (GMNIA) results showed very good agreements with negligible differences. The information concerning the differences between current Eurocodes EN 1993-1-1:2005 and EN 1999-1-1:2007 is provided. Working drafts of Eurocodes of new generation prEN 1993-1-1:2020 and prEN 1999-1-1:2020 are also commented on.

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“…The left column is stressed by compressive force F. The right column is stressed by compressive force δF with parameter. The meshing of the frame geometry was carried out using beam elements, where the elastic stiffness matrix and the geometric stiffness matrix were published in [8]. Each column was meshed with eighteen beam finite elements.…”

Section: Design Load-carrying Capacitymentioning

confidence: 99%

“…Initial imperfections are typically considered in advanced analyses [5,6]. Conventional methods of modelling imperfections are based on the scaling of the eigen buckling modes [7,8]. More advanced methods consider separately the system (out-of-plumb) and the bow (out of straightness) imperfections and thereby model more accurately the shapes and magnitudes of initial curvatures obtained from the results of experimental research, see for e.g [9].…”

Section: Introductionmentioning

confidence: 99%

Probabilistic Verification of Structural Stability Design Procedures

Kala¹

2018

TOCIEJ

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Introduction: This contribution presents a comparison of three methods of the statistical computation of the design load-carrying capacity of a steel plane frame. Two approaches of the European Standard Eurocode 3 and one stochastic approach are applied. The stochastic approach takes into account the random influence of all imperfections and can be applied to the reliability verification of design according to Eurocode 3. Methods: The columns and beams in the steel frame are modelled with beam elements using the stability solution with buckling length and the geometrically nonlinear solution. The stochastic computational model is based on the geometrically nonlinear solution and on the random influence of initial imperfections, whose random samplings are simulated using the Monte Carlo method. Results and Conclusion: The design load-carrying capacity of the steel plane frame computed using the stability solution with buckling length is in good agreement with the stochastic solution in which the design value is calculated as 0.1 percentile. On the contrary, the geometrically nonlinear solution according to Eurocode 3 gives the lowest (safest) values of design load-carrying capacity.

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Equivalent unique global and local initial imperfection - Imperfection in EN 1993-1-1 and EN 1999-1-1 Clause 5.3.2 (11) - calculation procedure and discovered obstacles

Cited by 3 publications

References 14 publications

Investigation of metal built-up columns Part II: Results

Investigation of metal built-up columns Part II: Results

Assessment of in-Plane Behavior of Metal Compressed Members with Equivalent Geometrical Imperfection

Probabilistic Verification of Structural Stability Design Procedures

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