Lateral pressure effects on the progressive hull collapse behaviour of a Suezmax-class tanker under vertical bending moments

Abstract

This paper presents the results of an investigation of the effect of lateral pressure on the progressive hull collapse behaviour of a double-hull oil tanker subject to vertical bending moments in both the sagging and hogging conditions. As an illustrative example, a Suezmax-class double-hull oil tanker designed by the Common Structural Rules (CSR) method is considered. The ANSYS nonlinear finite element method (NLFEM) is employed for the progressive hull collapse analysis. The effects of lateral pressure – static (anchored condition) and dynamic (operating condition) – are investigated in both the full-load and ballast conditions. To check the accuracy of ultimate hull girder strength analysis methods, Dow's test hull is also applied together with Suezmax class oil tanker under conditions of vertical bending moment but without lateral pressure loads. In this regards, the NLFEM method is compared with ALPS/HULL intelligent supersize finite element method (ISFEM) programs and International Association of Classification Societies (IACS) CSR method, which applies the idealized structural unit method (ISUM) (also called the Smith method). The important insights developed from the present study are documented.