【作者】 崔连琼；

【导师】 陈顺怀；

【作者基本信息】 武汉理工大学 ， 船舶与海洋结构物设计制造， 2008， 硕士

【摘要】 最优化问题是一个古老的问题,追求目标的最优化一直是人类的理想。许多工程优化问题往往性质十分复杂,很难用传统的优化方法来求解。而且实际的工程优化问题中大多数是多目标优化问题,各子目标之间一般都存在互相冲突的现象。多目标与单目标优化问题的本质区别是,前者一般是一组或多组非劣解的集合,而后者只是单个解或一组不连续的解。因此,多目标优化问题的求解变得困难。自60年代以来,人们对求解多目标优化问题的兴趣日益增加。一种模仿生物进化过程的、被称为“进化算法(Evolutionary Algorithm)”的随机优化技术应运而生,而且在解这类优化问题中显示出了优于传统优化算法的性能。而遗传算法(Genetic Algorithm)是迄今为止进化算法中应用最多、比较成熟、广为人知的算法。由于其在求解复杂优化问题的巨大潜力及其在工业工程领域的成功应用,这种算法受到了广泛的关注。经过几十年的发展,多目标遗传算法已经日趋成熟。船舶的优化设计是从60年代末期开始逐渐发展起来的一种有效、新的设计方法。船舶优化设计同许多其他工程问题一样属于多目标优化问题。其中船舶型线优化设计通常是以应用数学方法对型线进行光顺,而以船体的布置、水动力和结构性能为目标函数。型线优化设计是一个亟待解决的复杂多目标优化问题。本文以多目标遗传算法为主要研究内容,将改进的遗传算法应用于求解多目标优化问题并用于船舶优化设计是很有意义的。本文介绍了遗传算法的起源、历程、主要研究方向、遗传算法的基本原理以及改进措施等,编制基于改进的带精英策略的非支配排序遗传算法(NSGAⅡ)的通用多目标优化软件。本文以高速方尾船型优化为例介绍了多目标遗传算法在船型的型线优化设计当中的应用,找到了一种适合NPL 100 Model A船型的数学描述方法,在此基础上,以总阻力系数为优化目标,优化得到阻力性能优良的船舶型线。这说明多目标遗传算法在船型优化中的应用可以大大地提高了船舶优化设计质量、缩短设计周期。更多还原

【Abstract】 The optimization problem is an ancient question,and to get the optimization solutions has been humanity’s ideal.However,most project optimization problems are so complex that it is very difficult to solve them with the traditional optimization methods.Moreover most real project optimization questions are the multi-objectives optimization problems with more then one targets between which there exist conflicts mutually.The solution of multi-objectives optimization problems is a group or many groups of Non-inferior Set,while the simple target one always has only one solution or one group of non-continual solutions,which is the essential,distinguish between them.So it is much more difficult to solve the multi-objectives optimization problems.Since the 60s,people’s interest on solving the multi-objective optimization questions has increased day by day.And a kind of random optimize search method, called evolutionary algorithm,refer to the evolution law of biological circle was put forward.It is testified that this kind algorithm is of more excellent performance on solving the optimization problems than the traditional ones.And the genetic algorithm contained in the evolutionary algorithm is widely known and mostly used. It has received the widespread attention because of its great potential application in the solution of complex optimization question and actual project optimization problems.After several dozens year development,multi-objective genetic algorithm is already being mature day by day.Ships’ optimization design is a new effective design method which started from the late 60s and was developed gradually.As like as other actual project optimization problems,it is a multi-objectives optimization problem.And we always take hull’s arrangement,hydrodynamic force and structure performance as objective function to get the optimization body lines described by mathematics methods.The line optimization design is the complex multi-objective optimization question which urgently waits to be solvedThis paper study of multi-objective genetic algorithm and the application in multi-objectives optimization problems and optimization ship design.It is greatly significative.This paper,first of all,introduced the origin of genetic algorithm,the developing course,leading research direction,basic principle and the improved measures etc.and a Multi-Objective Optimization software base on NSGAⅡwas developed.Then,Optimization body lines Design of the high speed displacement transom stern ship was researched.In this paper,author find one mathematics description method of body lines which is suited for NPL 100 Model A,and then take the total resistance coefficient as the optimized goal,the optimization obtains a ship lines with better resistance performance.This proved that the application of multi-objective genetic algorithm can greatly enhance the ship design quality and shorten the design cycle time.更多还原