Structural Design and Optimization of an Ice Breaking Platform Supply Vessel

Abstract

In this thesis, the main objective is to do scantling, weight optimization and possible cost optimization for a platform supply vessel (PSV) for different polar classes with respect to the rules of Llyod’s Register. Taking polar class 2 as an example, scantling of hull structure was calculated based on equations in the rules (rules for PSV, for general cargo ships, for polar class vessel). According to the calculation and data first processed in Excel, all parameters affecting the scantling can be pointed out, which is critical for the later weight optimization. Regarding to the limitation of the rules, the structural optimization methodology has to be limited in the relationship of a variety of parameters in the equations. The main weight optimization operation was performed by MALAB according to all equations and constrains needed. The optimized result including dimension of plate, deck, framing and other elements was obtained in the final comparison. In optimization process, panel based optimization was programmed and the combination of serial and parallel algorithm was selected to optimize CPU time. After finding the relationship of variables by using Excel, quantitative relationship and trend between variables was analyzed by using MATLAB. The top appropriate solution corresponding with the criteria was founded based on the database created by MATLAB. As for some detailed design, this research will specially consider about. In this research, several important trends were concluded which could significantly influence the design process. Cost optimization is a complicated topic for any kind of ship involving variety of aspects. In this research, several main parameters including weight, welding length and part number were identified and taken into account for multi-objective optimization, which was made with the same optimization method. According to Pareto Frontier chart, suitable solution could be found with respect to specific weight of parameters. To check the optimized design, Rules Calc was selected to prove that the design satisfies the requirement of rules. According to plastic design theory, FEM was performed to prove the design is acceptable in strength.