Optimization procedure for liquid natural gas carrier structural design

• Published in: Proceedings of the Institution of Mechanical Engineers. Part M, Journal of engineering for the maritime environment Journal of engineering for the maritime environment, 2015-02, Vol.229 (1), p.14-35
• Main Authors: Zanic, Vedran, Andric, Jerolim, Hadzic, Neven
• Format: Article
• Language: English
• Subjects: Carriers; Cost engineering; Cost reduction; Design engineering; Design optimization; Finite element analysis; Finite element method; Freight forwarding; Liquefied natural gas; Liquids; Mathematical models; Natural gas; Optimization; Software; Transportation problem (Operations research)
• ISSN: 1475-0902; 2041-3084
• DOI: 10.1177/1475090213494195

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.