A Three-Dimensional Model for Strength Assessment of Type-C Independent Cargo Tank Structures

For the analysis of the arrangement and strength of Type-C independent cargo tank structures, the linear spring or rod elements are usually used to model supporting woods, in which one-dimensional and linear contact behaviors are assumed. This study aimed at developing a three-dimensional model for achieving more accurate strength assessment. In the model, solid elements are modeled to simulate the supporting woods. The nonlinear contact between the cargo tanks and the supporting woods is taken into account through LS-DYNA software. Numerical simulations of a 22,000-m3 liquefied petroleum gas carrier are carried out using both one-dimensional and three-dimensional models. Three load cases including one static and two dynamic cases are considered to assess the strength of the tank structures and supporting woods. The results obtained by the proposed model are compared with the results on the basis of spring elements. It is found that this new model can provide more reasonable strength predictions of the tank structures and the supporting woods. The method based on spring elements underestimates the wood stress, which indicates that it may be not conservative. Some discussions and suggestions are presented.