Optimization procedure for liquid natural gas carrier structural design

Abstract

The purpose of this article is to present the design procedure and the main results of its validation through the liquid natural gas carrier structural optimization. The work has been carried out through the EU FP6 project IMPROVE. The objective of the developed optimization process was to distribute the material more effectively in order to reduce weight/cost and to improve the structural safety in the allocated time frame. A coarse mesh finite element method model (three holds) has been developed, using MAESTRO software. Strength calculation has been carried out according to the Bureau Veritas Rules for direct calculation. Sensitivity analysis has been performed to investigate the influence of web frame spacing, longitudinal stiffener spacing and material type on the specified design objectives. Design procedure applied for the structural optimization of the liquid natural gas structure (one cargo hold) resulted in mass decrease of about 424 t (after standardization of scantlings), or 10.8%; the cost of the structure was reduced by about 5%; structural safety was increased and vertical center of gravity was slightly reduced by about 20 cm compared to the prototype structure.

Keywords

Liquid natural gas carrier ship structural design structural optimization procedure finite element method model

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