12. Design Procedure Based on Reliability Analysis of Ship Structure

In this paper, a general discussion is made on the design procedure based on reliability analysis, where a "direct method" and "semi-direct method" are proposed for the strength assessment of structural members of ships. The direct method is composed of system analysis, reliability analysis and design criteria; while the semi-direct method is simplified and less time-consuming procedure, but rational due to its strength criteria based on the failure probability concept as obtained by the reliability analysis. As a numerical example, the reliability analysis is performed on both longitudinal strength members and transverse members of an oil tanker, taking into consideration of such failure modes including yield failure of material, buckling and instability failure of deck or bottom plating, longitudinal and transverse webs, plastic bending collapse of hull girder and of transverse ring frame structure as well as fatigue crack initiation of butt welded joint of the primary strength members of the ship.