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Sofyan Ahmad - One of the best experts on this subject based on the ideXlab platform.
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Perancangan Struktur Underwater Habitat Dengan Konfigurasi Silinder Berujung Dome
2005Co-Authors: Sofyan AhmadAbstract:Laporan tugas akhir ini membahas perancangan awal Underwater Habitat, pada khususnya dalam segi kekuatan strukturnya untuk menahan beban tekanan ekstemal akibat dari kedalaman operasi. Underwater Habitat yang dijadikan objek penelitian mempunyai konfigurasi silinder berujung dome yang akan dioperasikan pada kedalaman air sampai dengan 1150feet (381m). Obyek dibangun dengan material HY80 High Tension Steel, dengan ukuran utama: panjang silinder 300 in, diameter silinder I 80 in, dan diameter dome setengah bola 180 • in, akan menerima pembebanan sebesar 567 Psi (39,1 bar) berupa tekanan hidrostatik ekstemal. Kajian kekuatan selanjutnya didasarkan pada tingkat ketebalan minimum kulit (shell) dan jarak. mak.simum penegar cincinnya (inner Ring Stiffener), dengan pemodelan metode elemen hingga menggunakan MSC. Nastran for Windows Version 4.5. Dari hasil analisa diketahui bahwa ketebalan minimum shell yang dapat digunakan adalah 1,6 in dan jarak mak.simum antar Stiffener adalah 50 in. Sturktur underwater habitat mempunyai kekuatan yang memadai sebagaimana ditunjukkan oleh faktor keselamatan SF yang diperoleh, yaitu sebesar 1,02 dan 1,4, masing-masing untuk kemampuan tekanan minimum dan tegangan maksimumnya, yang keduanya diindikasikan terjadi pada bagian dome. Kata-kata kunci: Underwater Habitat, konfigurasi silinder-dome, tekanan hidrostatik kedalaman operasi, tebal kulit dan jarak penegar cincin, kekuatan struktu
Warimantouw Ferdinand - One of the best experts on this subject based on the ideXlab platform.
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Perancangan Struktur Underwater Habitat Dengan Konfigurasi Silinder Tirus Berujung Dome
2006Co-Authors: Warimantouw FerdinandAbstract:Laporan tugas akhir ini membahas perancangan awal struktur Unden..ater Habitat, khususnya mengenai segi kekuatan struktur untuk menahan beban tekanan eksternal akibat kedalaman operasi. Underwater Habitat yang dijadikan objek penelitian mempunyai konfigurasi silinder tirus berujung dome yang dioperasikan pada kedalaman air hingga 1250 feet (381 m). Obyek dibangun dengan material HYIOO High Tension Steel , dengan ukuran utama: panjang silinder tirus 360 in, diameter terbesar silinder tirus 240 in, diameter terkecil silinder tirus 112,3 in, dan diameter dome masing-masing adalah : dome hemisperical 240 in, dan dome elipsoidal 112,3 in yang menerima beban tekanan hidrostatik eksternal sebesar 567 Psi (39,1 bar). Kajian kekuatan selanjutnya didasarkan pada tingkat ketebalan minimum kulit (shell) dan jarak maksimum penegar cincinnya (inner Ring Stiffener), dengan pemodelan ''metode elemen hingga'' menggunakan MSC. Nastran for Windows Version 4.5. Dari hasil analisa diketahui ketebalan minimum shell adalah 2,3 in dan jarak maksimum antar Stiffener adalah 60 in. Struktur underwater habitat mempunyai kekuatan tekan memadai yang ditunjukkan oleh faktor keselamatan SF sebesar 1,33 pacta silinder tirus berpenegar, 1,21 pada dome hemisperical. dan 1,08 pacta dome e/ipsoidal. Tegangan maksimum terjadi pada sambungan antara silinder tirus dengan dome hemisperical. Struktur silinder tirus memiliki titik tegang maksimum hanya pacta sisi dome dengan diameter terbesar
Cho Hyunman - One of the best experts on this subject based on the ideXlab platform.
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a numerical study on the static strength of tubular x joints with an internal Ring Stiffener
Journal of the Computational Structural Engineering Institute of Korea, 2005Co-Authors: Ryu Yeonsun, Cho HyunmanAbstract:The objective of this paper is to numerically assess the behavior of tubular X-joints with an internal ing Stiffener, and to evaluate the reinforcement effect of a Ring Stiffener, and to establish the strength formulae. Nonlinear finite element analysis is used to compute the static strength of axially loaded tubular joints. Numerical and experimental results are in good agreement for tubular X-joints. The chord lengths of simple and Ring-stiffened X-joints are suggested to reduce chord end effect. And, internal Ring Stiffener is found to be efficient In improving static strength of tubular X-joints. Maximum strength ratios are calculated as . Regression analyses are performed consideRing practical size of Ring Stiffener and strength estimation formulae for tubular X-joints with an internal Ring Stiffener are proposed.
J. M. Rotter - One of the best experts on this subject based on the ideXlab platform.
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A simple remedy for elephant's foot buckling in cylindrical silos and tanks
Multi-Science, 2006Co-Authors: Jf Chen, J. M. Rotter, Jg TengAbstract:Metal silos and tanks are susceptible to an elastic-plastic instability failure at the base boundary condition which is known as "elephant's foot buckling", due to its characteristic shape. This form of buckle occurs under high internal pressure accompanied by axial forces in the shell structure. Current international standards for both the static design and earthquake design include a provision to ensure that this failure mode is prevented. However, the only available remedy is currently to increase the wall thickness of the bottom course or strake. In this paper, an alternative method of strengthening against elephant's foot buckling is explored in which a light Ring Stiffener is used at a critical location. The strengthened shell is analysed using linear elastic bending theory in this preliminary study. Within the scope of this research, the strengthening effect is shown to be sensitive to the size and location of the Ring Stiffener. Rings that are too small and Rings that are too large both cause the strengths to be lower than that when the optimal Ring size is used. This is, therefore, an interesting example of structural behaviour in which the provision of a larger amount of material than the optimum leads to reduced strength.Department of Civil and Environmental Engineerin
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A Simple Remedy for Elephant's Foot Buckling in Cylindrical Silos and Tanks
Advances in Structural Engineering, 2006Co-Authors: Jian Fei Chen, J. M. Rotter, Jin-guang TengAbstract:Metal silos and tanks are susceptible to an elastic-plastic instability failure at the base boundary condition which is known as “elephant's foot buckling”, due to its characteristic shape. This form of buckle occurs under high internal pressure accompanied by axial forces in the shell structure. Current international standards for both the static design and earthquake design include a provision to ensure that this failure mode is prevented. However, the only available remedy is currently to increase the wall thickness of the bottom course or strake. In this paper, an alternative method of strengthening against elephant's foot buckling is explored in which a light Ring Stiffener is used at a critical location. The strengthened shell is analysed using linear elastic bending theory in this preliminary study. Within the scope of this research, the strengthening effect is shown to be sensitive to the size and location of the Ring Stiffener. Rings that are too small and Rings that are too large both cause the ...
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Effective cross sections of asymmetric Rings on cylindrical shells
Journal of Structural Engineering, 1998Co-Authors: Jian Fei Chen, J. M. RotterAbstract:Rings or Ringbeams are often used to stiffen cylindrical tanks, silos, towers, and pressure vessels. A Ring acts together with the axisymmetric shell to form a composite structure. The structural analysis of such a composite structure under general loadings is usually not simple, and often has to be numerical. Although the membrane stress in a symmetrical Ring Stiffener under axisymmetric loadings may be calculated from a simple effective Ring analysis, no existing simple method is able to predict the bending stresses caused by either eccentric loading (bending moment) or the use of an asymmetric section as a Ring Stiffener. In this paper, the deformations of a general unsymmetrical Ring Stiffener are analyzed using linear shell bending theory. A new rational method of determining both the precise membrane and the bending stresses throughout the discrete Ring Stiffener using effective Ring analysis is devised. The new method is suitable for use in a shell design standard.
Jg Teng - One of the best experts on this subject based on the ideXlab platform.
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A simple remedy for elephant's foot buckling in cylindrical silos and tanks
Multi-Science, 2006Co-Authors: Jf Chen, J. M. Rotter, Jg TengAbstract:Metal silos and tanks are susceptible to an elastic-plastic instability failure at the base boundary condition which is known as "elephant's foot buckling", due to its characteristic shape. This form of buckle occurs under high internal pressure accompanied by axial forces in the shell structure. Current international standards for both the static design and earthquake design include a provision to ensure that this failure mode is prevented. However, the only available remedy is currently to increase the wall thickness of the bottom course or strake. In this paper, an alternative method of strengthening against elephant's foot buckling is explored in which a light Ring Stiffener is used at a critical location. The strengthened shell is analysed using linear elastic bending theory in this preliminary study. Within the scope of this research, the strengthening effect is shown to be sensitive to the size and location of the Ring Stiffener. Rings that are too small and Rings that are too large both cause the strengths to be lower than that when the optimal Ring size is used. This is, therefore, an interesting example of structural behaviour in which the provision of a larger amount of material than the optimum leads to reduced strength.Department of Civil and Environmental Engineerin
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Elastic buckling of Ring-stiffened cone-cylinder intersections under internal pressure
Pergamon Press, 1999Co-Authors: Jg TengAbstract:Cone-cylinder intersections are commonly found in pressure vessels and piping. Examples include conical end closures to cylindrical vessels and conical reducers between cylinders of different radii. In the case of a cone large end-to-cylinder intersection under internal pressure, the intersection is subject to a large circumferential compressive force. Both the cone and the cylinder may be thickened near the intersection to resist this compression, but it is often convenient and necessary to augment further the strength of the intersection using an annular plate Ring Stiffener. Under this large circumferential compression, the intersection may fail by elastic buckling, plastic buckling or plastic collapse. This paper describes an investigation of the elastic buckling strength of Ring-stiffened cone-cylinder intersections. Two buckling modes are identified: a shell mode for thin intersections with a shallow cone (a cone with its apex half angle approaching 90°) and/or a relatively stocky Ring Stiffener, and a Ring mode for other cases. An existing elastic buckling approximation for annular plate Rings in steel silos is found to be applicable to the intersection when it buckles in the Ring mode. New approximate design equations are also established for the shell mode. In addition, simple expressions are identified which relate the number of circumferential buckling waves to the geometric parameters of the intersection.Department of Civil and Environmental Engineerin
