Keratan keluli tirus biasanya digunakan dalam industri pembinaan kerana nilai ekonominya ditambah dengan mengurangkan bahagian di kawasan tekanan rendah. Selain itu, dalam usaha untuk mengurangkan kos, bukaan web telah diperkenalkan untuk mengurangkan isipadunya. Disertasi ini membentangkan tentang analisis unsur terhingga kilasan lengkokan sisi keratan keluli tirus dengan bukaan. Keputusan dinyatakan dari segi momen lengkokan. Analisis berangka pada mulanya terdiri daripada empat model utama iaitu dengan nisbah tirus 0.3 untuk 3.5m dan 5.5m panjang dan nisbah tirus 0.5 untuk 3.5m dan juga 5.5m panjang. Untuk mengkaji kesan ketebalan dan bukaan untuk momen lengkokan, 94 model telah dianalisis untuk tujuan kajian ini. Lima pembolehubah seperti ketebalan web, ketebalan bebibir, saiz bukaan, nisbah tirus, dan susunan bukaan telah diuji untuk mengkaji kesan bukaan web pada tingkah laku lengkokan. Rasuk keluli web tirus dengan saiz bukaan yang berbeza (0.2D, 0.3D, 0.4D, 0.5D, 0.6D dan 0.7D) telah dimodelkan untuk mengkaji kesan bukaan web pada rintangan lengkokan. Saiz bukaan dari 0.2D hingga 0.4D adalah disyorkan kerana apabila saiz bukaan melebihi 0.4D, perbezaan kapasiti momen lengkokan cuma kira-kira 2% diperhatikan. Tambahan lagi, dengan meningkatkan nisbah tirus, luas bukaan web juga meningkat. Untuk semua saiz bukaan web dan nisbah tirus, corak kegagalan adalah hampir sama. Kesimpulannya, berdasarkan keputusan menggunakan kaedah unsur terhingga, ia menunjukkan bahawa bahagian keluli tirus tanpa bukaan mempunyai kapasiti momen lengkokan yang lebih tinggi. Perbezaan kapasiti momen lengkokan di antara keratan yang tanpa bukaan dengan keratan dengan bukaan yang disyorkan adalah di antara 2% sehingga 4%.
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Tapered steel section is normally used in the construction industry due to their added economic value by reducing the member section in the low stresses area. Also, with the aim of reducing the cost, web opening was introduced to reduce its volume. This dissertation presents the finite element analysis of lateral torsional buckling of tapered steel section with perforation. The results are expressed in terms of buckling moment. The numerical analysis initially consist of four main models with ratio of tapering 0.3 for 3.5m and 5.5m span and ratio of tapering 0.5 for also 3.5m and 5.5m span. With the purpose of studying the effect of thickness and the openings on the buckling moment, 94 models were analyzed. Five variables such as thickness of web, thickness of flange, opening size, ratio of tapering, and opening arrangement were investigated to study the effect of web opening on the buckling behaviour. Tapered web steel beams with different size of opening (0.2D, 0.3D, 0.4D, 0.5D, 0.6D and 0.7D where D is the depth of section at opening location) were established to investigate the effect of web opening on the buckling resistance. Opening size from 0.2D to 0.4D is recommended because when opening size exceeds 0.4D, buckling moment capacity difference of only around 2% was observed. Ratio of tapering was observed to increase the web opening area. For all different sizes of web openings and ratio of tapering, the deformation patterns are almost similar. In conclusion, results of finite element analysis indicate that tapered steel section without perforation has the higher buckling moment capacity. The buckling moment difference between non-perforated section with the recommended perforated section is around 2% to 4%.
Finite element analysis of lateral torsional buckling behaviour of tapered steel section with perforation / Ahmad Faiz Azar