Structural Optimization Design And Reliability Analysis For Cargo Tank Region Of Oil Tankers Based On Common Structural Rules

Common Structural Rules for Double Hull Oil Tankers (short for CSR) advocates more secure and more comprehensive standard system, and affect structural design of oil tankers comprehensively and systematically, especially the increase of hull structure weight. The key work is to make the design of cargo tank region reasonable, meanwhile, here is an important practical significance to seek structural optimization design of hull midship section which can achieve the lightest structure weight or the lowest cost under the variety constraints, and reliability analysis on this basis.This paper studies calculation of weight of metallic hull, from estimatig way to subtle way, and then takes an oil tanker as an example to realize optimization design and reliability analysis.Three works have been done as below.(1) This paper, according to the requirement of initial ship design, studies the estimation method of hull steel weight, and use index mathod and regression analysis to attain the empirical formula which can estimate the steel weight rapidly during determining the main scale and can also be fit for the design based on CSR rules. This article also analyzes the first oil tanker regested to the CCS based on CSR rules, and summarizes the subtle way to add up fast, not to leave out or repeat. At last using the same structure style, another plan is designed based on CCS rules, and the comparison result of weight of metallic hull is showed.(2) According to the contradiction of increasing lightweight resulting from the CSR, in this paper an optimization design, which can achieve minimum area of members in midship section under the constraints of longitudinal bending strength, local strength, rigidity-sacle ratio and so on, is drew up by using Visual Basic based on the CSR.Meanwhile, this reseach take a 50000DWT oil tanker as an example to decrease structure weight of longitudinal members by 5.801%, which proves the validity of this design method .(3) In view of the disadvantages of too large security margin, this paper introduces the reliability concept and completes reliability analysis of the three plans which are among the design based on CCS, initial design based on CSR and its optimization design.