عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The beam columns are under the influence of bending and compression, given that the buckling occurs in these members in one of the lateral, torsional and lateral-torsional forms, the bending moment and compressive axial force ratio have a significant effect on the behavior of the buckling. This paper investigates the performance of thin-walled closed box steel boxes under different loading conditions, concentrated load in the middle of the span, and a uniform distributed load with finite element method and with two-headed joint supported conditions in the range of elastic behavior. The tenth topic of the National Building Regulations, due to the large buckling limit moment from the yield limit buckling, does not occur in any global buckling, however, it mentions the probability of occurrence of lateral buckling in the range of post-elastic deformations for seismic beams. The results of this study show that in the presence of flexural loads, the buckling mode of the sections studied varies from the lateral buckling to the lateral-torsion, and the greater the ratio of the flexural loads to the axial loads, the torsional deformations will be greater. But, in the presence of bending loads on the buckling plane, the buckling mode of the sections in a certain amount of bending load will change from the global buckling to the local buckling. Compared to the three loading, the lowest M/P ratio, which leads to a global buckling, is related to the uniform distributed loading. By choosing the correct support condition in terms of the rotation around each of the fender members, and the appropriate shape of the box section, the strength of the member under the compression axial force-bending moment can be improved
 طاحونی، ش.، رحیملبافزاده، م. ص. و شلالوند، ب.، فناوری ساختمانهای فلزی، تهران، شرکت چاپ و نشر کتابهاى درسى ایران، چاپ ششم 1394، 232 صفحه.
 علینیا، م. م.، تئوری صفحات و پوستهها. تهران، انتشارات آشیان، چاپ چهارم 1395، 352 صفحه.
 Mohri, F., Bouzerira, C. and Potier-Ferry, M., Lateral buckling of thin-walled beam-column elements under combined axial and bending loads. Thin-Walled Structures, vol 46, 2008, pp 290-302.