Abstract. The brace configuration plays an important role to the ultimate strength of fixed jacket platform. The braces against the combined load in vertical and horizontal direction. In the present study, the ultimate strength of the fixed jacket platform is analysed considering the shape of the structural geometric. Four types of brace configuration namely, K, N, X and Y are taken to be assessed. Dimensions of the structure are constant including properties and materials. The boundary conditions are assumed to be fixed at the bottom part. The Non-Linear Finite Element Analysis (NLFEA) is adopted to calculate the ultimate strength of the structure and those results of brace configuration are compared with one another and discussed in the present study.

Abstract. The objective of the present research is to study the ultimate strength of ship's hull considering cross section and beam finite element under longitudinal bending. The single hull bulk carrier and double hull oil tanker are taken to be analysed. The one-frame space of ship is considered in the calculation. The cross section of ship's hull is divided into element composed plate and stiffened plate. The cross section is assumed to be remained plane and the simply supported is imposed to both side of the cross section. The longitudinal bending moment is applied to the cross section for hogging and sagging condition. The Smith's method is adopted and implemented into the in-house program of the cross section and beam finite element to calculate the ultimate strength of ship's hull. The result of the ultimate strength for hogging and sagging condition obtained by considering the cross section and beam finite element is compared with one another.

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In most relatively shallow waters, fixed platforms are the optimum economical choice. One of the important aspects of offshore fixed platform design is their installation procedure. Among the several conditions during installation, launching is probably the most critical. This operation has to be modelled and examined carefully in order to insure safe separation of jacket from barge. Sensitivity studies are performed to clarify the influences of the initial condition of launch barge to the jacket launch process. Launch analysis is carried out by using numerical simulation methods that supported by MOSES software. Jacket structure and launch barge are modelled on SACS and MOSES respectively. The jacket structure is laid on top of barge with the position of the top of jacket in the stern launch barge. Simulation results on the base case with a barge initial trim is 3.5° and a draft at midship is 6.1 m show that the jacket launch process can take place safely. Sensitivity analysis shows that the greater the trim angle and the initial draft of the barge the shorter the sliding speed and the reaction of the rocker arm decreases. While changes in the LCG jacket and the additional weight of the jacket have a significant effect on the bottom clearance and jacket free floating conditions after being separated from the launch barge.

Ro-Ro ship has special characteristic for cargo handling because the cargo is transferred in horizontal direction. For example, cars can move by using ramp door which is located in front and/or aft of the ship. In conjunction with this, car passenger and other decks such as top including bottom part need to be investigated for local and global of Ro-Ro ship structure. In the present study, the ultimate strength investigation of Ro-Ro ship is conducted. There are three types of Ro-Ro ships are taken as the ship’s subject. The cross section of Ro-Ro is considered in the analysis and it is modelled having plate and stiffened plate. The one-frame is represented in longitudinal direction. The simply supported of boundary condition is applied and the cross section is assumed to be remained plane. The calculation of the ultimate strength using in-house integrated program. The ultimate strength of Ro-Ro ship is investigated under hogging and sagging conditions. The vertical bending moment is imposed to the cross section to obtain the ultimate strength including their progressive collapse. The result obtained by in-house program for three types of Ro-Ro ships are summarized and the collapse behaviour for local and global of the decks to the ultimate strength of Ro-Ro ship are also presented in this study.