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Abstrak :
Analisis Kekuatan Sisa Penumpu Lambung Kapal Asimetris Pasca Rusak dengan Metode Beam Finite Element. Tujuan dari studi ini adalah untuk menganalisis kekuatan sisa dari penumpu lambung kapal rusak tidak simetris dalam pengaruh lentur memanjang. Metode Beam Finite Element diadopsi untuk pengujian dari kekuatan sisa dari dua kapal bulk carrier (Ship B1 dan Ship B4) dan sebuah model tiga-ruang-muat dari kapal bulk carrier dengan tipe Panamax berlambung tunggal pada kondisi hogging dan sagging. Suatu prosedur penyelesaian yang efisien dengan kata lain lambung kapal diasumsikan tetap pada bidang, momen lentur vertikal bekerja pada penampang dan model tiga-ruang- muat. Untuk kasus kerusakan, bagian yang rusak dibuat sederhana dengan menghilangkan elemen-elemen dari penampang, tegangan sisa pengelasan, dan ketidaksempurnaan awal diabaikan. Tidak ada perpanjangan retak yang dipertimbangkan. Hasil yang diperoleh dengan menggunakan metode Beam Finite Element disebut Beam-HULLST dibandingkan dengan analisis progressive collapse yang diperoleh dengan menggunakan HULLST untuk validasi dari metode yang digunakan. Kemudian, pada model tiga-ruang-muat, digunakan Beam-HULLST untuk menginvestigasi pengaruh rotasi sumbu netral pada kondisi intact dan damage dengan mempertimbangkan satu dan lima jarak gading.

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The objective of the present study is to analyze the residual strength of asymmetrically damaged ship hull girder under longitudinal bending. Beam Finite Element Method is used for the assessment of the residual strength of two single hull bulk carriers (Ship B1 and Ship B4) and a three-cargo-hold model of a single-side Panamax Bulk Carrier in hogging and sagging conditions. The Smith?s method is adopted and implemented into Beam Finite Element Method. An efficient solution procedure is applied; i.e. by assuming the cross section remains plane, the vertical bending moment is applied to the cross section and three-cargo-hold model. As a fundamental case, the damage is simply created by removing the elements from the cross section, neglecting any welding residual stress and initial imperfection. Also no crack extension is considered. The result obtained by Beam Finite Element Method so-called Beam-HULLST is compared to the progressive collapse analysis obtained by HULLST for the validation of the present work. Then, for the three-hold-model, the Beam-HULLST is used to investigate the effect of the rotation of the netral axis both intact and damage condition taking the one and five frame spaces into account.

Abstrak :
The fixed jacket is still the most common offshore structure used for drilling and oil production. The structure consists of tubular members interconnected to form a three-dimensional space frame, which can be categorized into a column structure. The structure usually has four to eight legs that are battered to achieve stability against axial compressive loads and toppling due to wave loads. The configuration of a typical member on the jacket structure has significant influence on buckling and fatigue strength. Horizontal and diagonal braces play an important role in resisting the axial compression and wave load on the global structure. This paper discusses the effect of symmetrical and asymmetrical configuration shapes in buckling and fatigue strength analysis on two types of fixed jacket offshore platforms. The axial compressive and lateral (wave) loads were considered and applied to both structures. The material and dimensions of the two structures were assumed to be constant and homogenous. Crack extension and corrosion were not considered. To assess the buckling and fatigue strength of these structures, due to the symmetrical and asymmetrical configuration shape, the finite element method (FEM) was adopted. Buckling analysis was performed on these structures by taking two-dimensional planes into consideration to obtain the critical buckling load for the local plane; fatigue life analysis was then calculated to produce the fatigue life of those structures. The result obtained by FEM was compared with the analytical solution for the critical buckling load. The stress-strain curve was also applied to show the difference between symmetrical and asymmetrical shapes. For fatigue life analysis, the procedure of the response amplitude operator was applied.

Abstrak :
The fixed jacket is still the most common offshore structure used for drilling and oil production. The structure consists of tubular members interconnected to form a three-dimensional space frame, which can be categorized into a column structure. The structure usually has four to eight legs that are battered to achieve stability against axial compressive loads and toppling due to wave loads. The configuration of a typical member on the jacket structure has significant influence on buckling and fatigue strength. Horizontal and diagonal braces play an important role in resisting the axial compression and wave load on the global structure. This paper discusses the effect of symmetrical and asymmetrical configuration shapes in buckling and fatigue strength analysis on two types of fixed jacket offshore platforms. The axial compressive and lateral (wave) loads were considered and applied to both structures. The material and dimensions of the two structures were assumed to be constant and homogenous. Crack extension and corrosion were not considered. To assess the buckling and fatigue strength of these structures, due to the symmetrical and asymmetrical configuration shape, the finite element method (FEM) was adopted. Buckling analysis was performed on these structures by taking two-dimensional planes into consideration to obtain the critical buckling load for the local plane; fatigue life analysis was then calculated to produce the fatigue life of those structures. The result obtained by FEM was compared with the analytical solution for the critical buckling load. The stress-strain curve was also applied to show the difference between symmetrical and asymmetrical shapes. For fatigue life analysis, the procedure of the response amplitude operator was applied.