Muhammad Zubair Muis Alie

The Ultimate Strength of Double Hull Oil Tanker Due to Grounding and Collision

The damaged tanker by grounding and collision may totally collapse if loss its buoyancy, stability and suffer structural failure. The objective of the present study is to investigate the ultimate strength of double hull oil tanker under vertical bending moments due to grounding and collision. The damages are modelled by removing the elements consist of stiffened and unstiffened plates from the damages part. One-frame space of the double hull oil tanker is taken to be analysed. Two damages cases are considered in the analyses those are grounding and collision. The transversal damage extent for grounding are 10%, 25%, 40% and 55%. The groundings are placed at symmetric position on the outer bottom part. For the case of collision, the vertical damage extent are taken as 10%, 20%, 40% and 60%. The transversal damages extent is taken to be B/16 and it is constant for all collision damages. The investigation of the ultimate strength is performed by the Non-Linear Finite Element Analysis method under moment control. The boundary condition is applied with fully constrained on all nodes at the aft-end, while the rigid linked on all nodes is attached at the fore-end with respect to the reference point on the neutral axis. The initial imperfection, welding residual stress and crack are not considered in the analyses. The results obtained by Non-Linear Finite Element Analyses for the ultimate strength are compared with the in-house program using Smiths method implemented in HULLST. The stress distribution and deformation for every case of damages including intact are also discussed in the present study.

Collapse Analysis on VLCC Subjected to Longitudinal Bending with Damages

The objective of the present study is to analyze the progressive collapse of VLCC hull girder with damages subjected to longitudinal bending. For the simple case, the cross-section is assumed to be remained plane and the vertical bending moment is applied to the cross section. The residual stress, initial imperfection, and crack are not considered. The damages scenarios are located at the center part and asymmetric position of the cross section. To analyze the progressive collapse including its behavior of VLCC ship hull, the simply supported is imposed to the cross section and taking the hogging and sagging condition into account. The results obtained for intact and damages condition by the analytical solution is compared and summarized with one another.

Finite Element Analysis on the Hull Girder Ultimate Strength of Asymmetrically Damaged Ships

ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering OMAE2016

BUCKLING ANALYSIS ON PECHIKO FIELD OF FIXED OFFSHORE PLATFORM IN MAKASSAR STRAIT

One of the most important criterion in the design of fixed offshore platform is to have strength from applied loads which is acting perpendicular to jacket leg section such as axial compression.The axial compressive load acts vertically downward to jacket legs and the deformation on the jacket legs in horizontal direction due to this load is called buckling. In the present study, buckling analysis on pechiko field of fixed offshore platform is performed using Finite Element Analysis (FEA). The fixed jacket platform namely tripod and tetrapod are taken as the object of the analysis. Only the axial compressive load is used in the analysis and the boundary conditions are assumed to be fixed both tripod and tetrapod at the bottom seabed. As a fundamental case, buckling analysis is carried out in plane-section (2D analysis), then the result obtained by FE analysis is compared with the analytical solution.It is found that the result obtained by FE analysis for the critical buckling load is in good agreement with the analytical solution, and the applicability of FE analysis is further used to investigate the deformation of 3D model.