Çift simetri eksenli I-enkesitli çelik elemanların doğrusal değişen momentler altındaki yanal burulmalı burkulma davranışı

Çelik yapılardaki teknik gelişmeler ve daha geniş uygulama alanları nedeniyle yapısal stabilite problemleri üzerine yapılan araştırmaların önemi artmaktadır. Yanal burulmalı burkulma, özellikle kuvvetli eksenlerinde eğilmeye maruz kalmış çift simetri eksenli I-kesitli çelik elemanlar için önemli bir sorundur. Bu elemanlar yatay yer değiştirme ve dönmeye karşı uygun bir şekilde desteklenmezlerse, yük taşıma kapasitelerine ulaşamadan önce yanal burulmalı burkulma riski altındadırlar. Bu çalışmada, farklı uç moment etkisi altındaki çift simetri eksenli I-kesitli çelik elamanların elastik yanal burulmalı burkulma davranışı, önerilen bir yöntem ile birlikte çeşitli tasarım standartları, literatürdeki yaklaşımlar ve sonlu eleman analizleri dikkate alınarak incelenmiştir. Burada önerilen yöntem, doğrusal değişen moment etkisi altında yanal burulmalı burkulma davranışını temsil eden diferansiyel denklemin sonlu farklar yöntemi ile çözümüne dayanır. Kritik moment ve moment düzeltme faktörü açısından bu yaklaşımları karşılaştırmak ve değerlendirebilmek için farklı yatay yönde tutulma uzunlukları ve çeşitli uç moment değerleri dikkate alınmıştır. Analiz sonuçları, yanal burulmalı burkulmanın, eğilme altında bulunan çift simetri eksenli I-kesitli çelik elemanlar için önemli bir konu olduğu ve önerilen yöntem ile tasarım standartları, literatürdeki yaklaşımlar ve sonlu elemanlar sonuçları ile karşılaştırıldığında sonuçların tatmin edici bir şekilde yansıtıldığını göstermektedir.

Anahtar Kelimeler:

Yanal burulmalı burkulma, Çift simetri eksenli I-kesitli çelik eleman, Çelik yapı tasarımı, Moment düzeltme katsayısı

Lateral torsional buckling of doubly symmetric I-shaped steel members under linear moment gradient

Due to technical developments and wider range of applications in the steel structures, significance of the research on structural stability problems become forward. Lateral torsional buckling is a major problem especially for doubly symmetric I-shaped steel members subjected to flexure about their strong axis. If these members are not appropriately braced against lateral deﬂection and twisting, they are under the risk of failure by lateral torsional buckling prior to the reach their load carrying capacity. In this study, elastic lateral torsional buckling behavior of doubly symmetric I-shaped steel members under linear moment gradient is investigated considering a proposed method, several design standards and codes, approaches from the literature and finite element analysis. Proposed method herein is based on finite difference solution of lateral torsional buckling differential equation considering linear moment gradient. Different unbraced member lengths and various end moment values are considered in order to compare and evaluate these approaches in terms of critical moment and moment modification factor. Analysis results show that lateral torsional buckling is a key issue for doubly symmetric I-shaped steel members that are under flexure and it is reflected satisfactorily with the proposed method considering the design codes and standards, approaches from the literature and finite element analysis results.

Keywords:

eral torsional buckling, Doubly symmetric I-shaped steel member, Structural steel design, Moment modification factor,

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