Multidisciplinary Optimization Research For The Ship Hydrodynamic Performance Design

The design of ship hydrodynamic performance was a crossover design process which involved multi-disciplines.As all disciplines were influenced each other,it needed to be coordinated in the design process,so it is an engineering system design problem.Multidisciplinary design optimization(MDO)had beeb recognized as an advanced theory and method to deal with these kinds of problem.Aimed at exploring and engineering application of the MDO method in the ship hydrodynamic performance design which including three sub-disciplines,a study of the ship hydrodynamic performance MDO were carried out,to provide innovation design theory and method.The main research contents and main results are put as follows.(1)A systematic study of the MDO basic theory and method was carried out and a review of the MDO research achievements was present in this paper.A lot of work had been done on the CO characteristics and modeling method study.Then,three CO models were proposed for the typical coupling systems accordingly,hope to promote the MDO modeling method being developed into standardization.In additionally,a modified for the CO was proposed to solve a special kind of optimization problem,and an effective application of the bulk carrier ship hydrodynamic design was carried out.(2)The ship hydrodynamic performance MDO put forward the new requirement on the evaluation methods.Then,a systematic collection and code development orient to the ship hydrodynamic performance MDO was carried out at the first time.As a results,a set of analysis mode for the ship range from lower to high speed performance evaluation was build up,including the performance of powering,seakeeping per and maneuver.Those code set would not only provide tools for MDO model,but also for the conventional performance evaluation and traditional optimization.(3)A MDO model that based on the CO algorithm was constructed to solve the ship hydrodynamic design problem,and the design of a bulk carrier ship as well as a high speed vessel was taken as example,both Pareto optimal solutions were obtained.The optimization results indicated that the overall performances were greatly improved,the average increase of the bulk was over 20% and 7% for the vessel,but,as he disciplinary optimization model become specialized,its efficiency was reduced.It revealed the fact that the application of MDO at the concept stage was more useful to improve the ship performance.(4)After take a short discussion on the importance of considering uncertainty in the design process to improve the quality of the product,the concept intent and formulation as well as analysis method of the uncertainty were studied.Then,main work was focus on the research of reliability-based and robust design technology,which was applied in the bulk carrier ship design again,and a reliable optimal solution as well as a robust reliable optimal solution was obtained,the reliability index was increased from 50% to 98% for the reliable optimum,and the max change range down more the 5% for the robust optimum.This may provide some experience and useful reference for further study.