Multi-level Pareto supported design methodology- application to RO-PAX structural design

Abstract

A novel decision support methodology for concept and preliminary design of a complex ship structure is described together with its application to the structural design of large a RO-PAX ship. The multi-criteria, multi-stakeholder design problem was solved using the suggested methodology with the support of a ship-owner, Classification Society and a shipyard. Developed methodology combines three design steps for the fast generation of a different design variants regarding topological (no. of decks), geometrical (bulkhead and deck positions) and scantlings variables. For each design step different structural FEM models, load models and optimization models have been established. In the final step the full ship 3D FEM model was developed to validate and synthesize the optimal design variant using safety, weight, cost and fatigue criteria. Decision making implied multi-objective decision making (MODM) and multi-attribute decision making (MADM) procedures based on dual SLP and MOPSO optimization algorithms all combined with the stakeholders' subjective decision making (selection) on the generated Pareto frontiers. The procedure resulted in the optimal structural design of the RO-PAX ship with two superstructure decks, increased parking area on lower decks, lower VCG position, etc., combined with the considerable savings in the ship lightweight and related savings in the fuel and other operational costs.