The Analysis Of Ultimate Strength Of 300,000DWT VLCC

It is very important to estimate the load carrying capacity of a ship's hull as a whole from the viewpoints of safety and economy. The concept of the longitudinal strength of ship hulls has changed and advanced greatly as the study on the failure mechanism of the hull is getting deep. By taking account the failure modes of yielding, buckling and their combination, as well as the non-liner interactions between structural members, the ultimate longitudinal bending moment is defined by the moment corresponding to the point with zero slope on the moment-curvature curve of the ship hull. The definition has considered as the most reasonable so far.The calculation of the ultimate longitudinal bending moment is extremely complicated because of the non-linearity both in material properties and in geometry of deformations. There are three main methods by far, non-linear finite element method, idealized structural unit method and simple method.In this article, the process of ultimate strength theory and analysis method are introduced for ship structure throughout the world. Then take the 308000 DWT VLCC for example, with DNV/SESAM professional program, the finite-element model is established according to the corresponding guide documents about ultimate strength developed by JTP, DNV and BV, The program of NAUTICUS and MARS2000 are adopted to calculate the ultimate strength of VLCC, the main objective of this article is to provide some references for structure design of VLCC.