Disertasi ini membentangkan kajian terhadap kelakuan struktur dan kecekapan keluli tirus dengan pembukaan elips di bawah keadaan beban ricih dan kilasan. Kesan pelbagai konfigurasi pembukaan elips seperti nisbah tirus, saiz bukaan, orientasi bukaan dan susunan perforasi pada prestasi struktur keluli tirus telah dikaji dengen menggunakan analisis unsur terhingga. Sejumlah 224 model teleh disimulasikan melalui perisian LUSAS untuk menjalankan kajian ini. Model yang paling efisien di bawah keadaan bebanan ricih adalah keluli tirus yang mempunyai nisbah tirus 0.3 dan bukaan elips yang bersaiz 0.2D dengan disusun dalam susun atur 3. Model ini mempunyai kecekapan ricih yang bernilai 1094.35, iaitu 4.12% kurang daripada keluli tirus tanpa pembukaan tetapi pengurangan berat keluli yang sebanyak 0.32% dapat dicapai. Didapati jika nisbah penirusan and bukaan semakin kecil, keupayaan lengkukan ricih dan kecekapan keluli tirus berbukaan elips akan semakin meningkat. Dalam keadaan beban kilasan, model yang paling cekap didapati adalah keluli tirus dengan nisbah tirus 0.3, saiz bukaan 0.5D yang disusun dalam susun atur 1 dengan tiga orientasi pembukaan elips yang berbeza memperoleh nilai kecekapan yang sama. Model yang paling effisien didapati mempunyai kecekapan kilasan sebanyak 9.38, bukan sahaja 5.51% lebih tinggi daripada keluli tirus tanpa bukaan tetapi juga membawa kepada pengurangan penggunaan bahan keluli sebanyak 5.25%. Didapati jika nisbah penirusan semakin meningkat, kapasiti menanggung beban keluli tirus dengan bukaan elips akan semakin meningkat. Walau bagaimanapun, kecekapan keluli tirus berbukaan elips menurun apabila nisbah penirusan meningkat. Tambahan pula, saiz bukaan yang berbeza menunjukkan bahawa jika saiz bukaan semakin kecil, kapasiti menanggung beban untuk keluli tirus dengan pembukaan elips semakin meningkat tetapi didapati penurunan kelakuan kecekapan. Susun atur bukaan didapati mempengaruhi keupayaan menanggung beban dan kecekapan keluli tirus dengan pembukaan elips bawah kedua-dua keadaan beban.
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This dissertation presents the study of structural behaviour and efficiency of tapered steel section with elliptical perforation under shear and torsion loading conditions. The effect of various elliptical perforation configurations such as tapering ratio, perforation size, perforation orientation and perforation layout on the structural efficiency of tapered steel section was investigated by using finite element method (FEM). A total of 224 models were simulated via LUSAS software in order to carry out this study. The most efficient model under the shear loading condition is the tapered steel section with tapering ratio of 0.3 and vertical elliptical perforation of 0.2D in size which arranged in layout 3. The most efficient model has a shear efficiency of 1094.35, which is 4.12% less than the tapered steel section without perforation but it could achieve a 0.32% of weight reduction. It was found that the smaller the tapering ratio and perforation size, the larger the shear buckling capacity and efficiency of the elliptical perforated tapered steel section. In terms of torsion loading condition, the most efficient models are found to be the tapered steel section with tapering ratio 0.3, perforation size of 0.5D which arranged in Layout 1 with all three different elliptical perforation orientations obtained the same highest efficiency value. The most efficient models have a torsional efficiency of 9.38, which are not only 5.51% higher than the tapered steel section without perforation but also lead to a reduction of 5.25% steel material usage. It was found that the larger the tapering ratio, the larger the load carrying capacity of the tapered steel section with elliptical perforation. However, the efficiency is decreases as the tapering ratio is increases. Moreover, the different in perforation sizes showed that the smaller the perforation size, the larger the load carrying capacity of the tapered steel section with elliptical perforation but a smaller value of efficiency is obtained. The perforation layout was found will be affected the load carrying capacity and efficiency of the elliptical perforated tapered steel section for both different loading conditions.
The efficiency of tapered steel section with elliptical perforation under shear and torsion behaviour / Sua Xing Yong