Ultimate Strength of a Capesize Bulk Carrier in Hogging and Alternate Hold Loading Condition

Abstract

The ultimate hull girder strength of a Capesize bulk carrier under combined global and local loads in hogging and alternate loading condition (AHL) is evaluated using nonlinear finite element (FE) analysis with ABAQUS software. A three-cargo-hold FE model with fine mesh in the middle cargo hold is developed for the nonlinear FE analysis. The initial geometrical imperfections are introduced in the double bottom of the middle cargo hold. Both material and geometrical nonlinearities are taken into account in the FE model. The most critical situation for the longitudinal strength assessment of bulk carriers in hogging is the AHL condition with middle cargo hold empty under combined global and local loads. The local loads, i.e. the external sea pressure and internal cargo pressure are adopted according to Common Structural Rules for bulk carriers (CSR-BC). The ultimate hull girder strength with various local pressure load levels is investigated for the heavy cargo AHL in hogging condition. It is found that the ultimate strength of the hull girder can be significantly reduced due to the action of the local pressure loads compared with that obtained under pure hogging bending.