A system for collapse and reliability analysis of ship structures using a spatial element model

Abstract

This paper is concerned with the ultimate strength and reliability analysis of ship's hull girders, which are composed of spatial membrane elements and subjected to combined static loads and extreme wave loads. First, a new method is proposed for generating safety margins of general plate structures. A linearized failure condition of an element is introduced which takes account of the yielding and buckling collapse under the plane stress condition. The failure criterion facilitates the generation of safety margins and the calculation of failure probabilities. Structural failure is defined as the generation of large deformations due to collapse. Probabilistically dominant failure modes are selected to applying the so-called branch-and-bound method. Finally, the proposed system is applied to a spatial plate structure for main hull girder of a 150 000 DWT bulk carrier under two loading conditions. Through comparison between numerical examples and other results using simple hull girder models, the applicability of the proposed system is demonstrated.