Advancing Engineering Critical Assessment for Eco-friendly Cargo Tanks: IMO Type-C Bilobe Tank

This paper presents a comparative analysis of Engineering Critical Assessments (ECA) for Eco-friendly Liquefied Gas Cargo Tanks using 2D and 3D finite element models. Thin plate structures modelled with shell elements generally provide high accuracy. However, when stress distribution varies across the thickness, solid models are more effective in capturing accurate stress intensity factors. Solid models pose challenges despite these advantages, such as increased complexity in accounting for thickness variations, weld bead geometry, and higher computational costs. Typically, tanks experience membrane stresses due to internal design pressure. However, areas with geometric discontinuities, which are susceptible to stress concentrations, exhibit significant bending stresses, highlighting the need for thicknessdependent stress evaluations. In this study, structural strength was evaluated in accordance with the IGC Code, while the ECA was performed following BS 7910 guidelines. The analysis compares shell and solid element results in stress concentration regions, focusing on membrane-to-bending stress ratios and the impact of weld bead modelling on stress concentrations. The findings contribute to enhancing the effectiveness of ECAs for IMO Type-C tanks.