Tekuk Torsi Lateral Balok I Kantilever Non Prismatis
DOI:
https://doi.org/10.5614/jts.2014.21.2.2Keywords:
Tekuk torsi lateral, Balok kantilever, Momen kritis elastis, Metode elemen hingga.Abstract
Abstrak. Dalam makalah ini disajikan hasil dari suatu studi tentang tekuk torsi lateral elastis balok kantilever dengan penampang I nonprismatis. Bentuk ketidak prismatisan adalah ketinggian badan (web) bervariasi linier sedangkan lebar sayap konstan. Untuk itu dilakukan analisis tekuk elastis sejumlah balok kantilever nonprismatis. Parameter yang ditinjau adalah parameter tak berdimensi balok untuk tekuk torsi lateral dan kemiringan sisi badan. Analisis dilakukan dengan menggunakan analisis tekuk linier metode elemen hingga yang dibantu program SAP versi 14. Formulasi metode elemen hingga berdasarkan teori bifurkasi. Teori ini menghasilkan suatu persamaan nilai Eigen. Momen kritis adalah nilai Eigen terkecil dari penyelesaian masalah nilai Eigen tersebut. Beban yang ditinjau adalah beban terpusat diujung bebas balok dan beban terbagi merata. Ditinjau juga pengaruh lokasi beban, yaitu beban bekerja pada pusat geser, beban bekerja pada sayap atas (sisi atas badan balok) dan beban bekerja pada sayap bawah (sisi bawah badan balok). Dari studi ini dapat disimpulkan bahwa kemiringan sisi badan berpengaruh kecil terhadap momen kritis balok bila beban bekerja pada pusat geser, akan tetapi pengaruh ketinggian letak beban terhadap pusat geser sangat dipengaruhi oleh kemiringan sisi badan. Selain itu telah didapat persamaan-persamaan untuk memperkirakan besarnya momen kritis elastis balok kantilever nonprismatis melalui analisis regresi terhadap data hasil metode elemen hingga.Abstract. This paper presents the results of a study about elastic lateral torsional buckling of web tapered cantilever I beams. Elastic buckling analysis was carried out on a number of web tapered cantilever I beam. Beam parameters are expressed in term of dimensionless parameter for lateral torsional buckling and the slope of the side of the tapered web. The analysis is performed using finite element method and the SAP 2000 v 14 program is used to do the analysis. The finite element formulation is based on bifurcation theory. This theory leads to Eigen Value Problem. Critical moment is the lowest Eigen value. The load to be considered is point load at the free end of the beam and uniformly distributed load. Three location of load are considered. The first is at shear center, the second is at top flange and the third is at the bottom flange.From this study, it can be concluded that the slope of the side of tapered web has little influence on the critical moment. But the influence of load height on critical moment is strongly influenced by the slope of the side of the tapered web. Equations for estimating the critical moment has been obtained by regression of the data results of the finite element method.
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