Optimum Design Of Large Crude Oil Tanker Structures Based On Direct Strength Calculation

Crude oil tankers built recently are mainly large tankers, which have complicated structures and consume large number of steels. So this kind of ships'structural optimization is very important. This paper do a research on holistic optimization of cargo tanks based on FEM and develop a software for optimization of large crude oil tankers based on FEM.Based on DNV, the paper optimized transverse structures of large crude oil tankers. Transverse structures are simply seemed as T bars. A 300,000DWT oil tanker's transverse structures are optimized by Mutative Scale Chaos Algorithm. The result shows the weight decreased 8.77% respectively, which gave a basis for the optimum of large crude oil tankers on FEM.The paper advanced a new approach for optimum of large crude oil tankers based on direct calculation, which integrates FEM, Uniform Design, Neural Network and Discrete Particle Swarm Algorithm. An optimum mathematic model is built. Based on JTP, the paper, using APDL of ANSYS creates a parameter FEM model which has three cargo tanks as a FEM platform of optimum. Using Uniform Design, the paper creates appropriate samples which are put into FEM model to calculate stresses. Furthermore, a Neural Network respond surface of design variables and stress respond is built. The medium cargo tank of a 300,000DWT crude oil tanker is optimized by Discrete Swarm Optimization Algorithm, and the result goes back to FEM to evaluate stresses. The result under the condition that all of stresses are fulfilled with stress standard shows that the weight decreased 3.64% respectively.Based on above works, the paper develops software according to software methodology to integrate each module to a platform of optimum for large crude oil tanker structures based on FEM. The software has a good human interface.