【作者】 陈炉云；

【导师】 王德禹；

【作者基本信息】 上海交通大学 ， 工程力学， 2008， 博士

【摘要】 多学科设计优化技术是近年来兴起的一门新技术。其主要设计思想是在复杂系统的整个设计过程中,通过分解和协调等手段将复杂系统分解成为与现有工程设计组织相一致的若干个子系统。充分利用分布式计算机网络技术来集成各个学科的知识或各子系统已有的知识,从全局的角度求解复杂工程系统设计的优化问题。本文以某型号潜艇结构在海水中的结构-声辐射优化为载体和实例进行多学科设计优化的研究工作,将多学科设计优化技术引入到具有典型多个学科耦合特点的结构-声辐射领域的优化设计中,以有效地改善潜艇结构的声学性能。本文在分析结构动力响应方程和声辐射方程基础上,建立了以结构声辐射功率为目标函数的结构-声辐射优化的数学模型,分析了结构-声辐射功率灵敏度。在文章中,分析了进行结构-声辐射多学科设计优化的基本流程,通过集成有限元软件和边界元软件,在多学科设计优化平台上运用遗传算法进行结构-声辐射优化分析。为建立一个声压目标函数与声功率目标函数之间的关系式,并评价场点的声压问题,引入了球形包络面模型。在计算实例中,研究了结构-声辐射的尺寸优化、肋骨分布优化和拓扑优化问题。结构尺寸优化分析了空气中的加肋板结构的声辐射优化问题和在水中的有限长双层加肋圆柱壳结构的声辐射优化问题。同时,运用声辐射功率灵敏度信息结合泰勒展开式,对加肋圆柱壳结构进行了结构-声辐射优化。以肋骨的位置为设计变量,进行了肋骨分布优化。此外,基于改进渐进结构优化法理论,对平板的结构-声辐射拓扑优化进行了探索性研究。最后分别运用声辐射功率灵敏度信息和多学科设计优化平台对某型号潜艇艉部结构进行了结构-声辐射优化分析。数值计算表明,通过优化其声学性能有了很大的改善,优化是有成效的。在本文完成的主要工作有:(1)运用保角映射理论,研究了直角空间域内的结构声辐射问题,分析了边界特性对声辐射功率和声指向性的影响,研究成果开拓了结构-声辐射边界特性的研究范围。(2)运用结构动力响应方程和声辐射方程,推导了声辐射功率的灵敏度公式。并将功率灵敏度信息用于加肋圆柱壳和潜艇结构的声辐射优化中,实现了声辐射优化的目的。(3)建立了以结构-声辐射功率为目标函数的数学模型。运用多学科设计优化理论,分析了进行结构-声辐射优化的流程并建立了相应的集成平台。(4)通过多学科设计优化集成技术,运用遗传算法进行结构-声辐射的尺寸优化、肋骨分布优化和拓扑优化研究。更多还原

【Abstract】 The multidisciplinary design optimization (MDO) is a new technology of late years. The general design principle of MDO can be described as followings: in the total design process, the complicated system can be decomposed into a lot of subsystems which are accordant with the current engineering design organization by decomposition and accordance, and different kinds of disciplinary or subsystems can be integrated by distributed computer net technology, so the optimism for complicated engineering systems can be solved integrally by global optimum.In this paper, the structural-acoustic radiation optimization of a submarine as example, the MDO technology is introduced to analysis the structural-acoustic optimization problem, and using the result to improve the submarine structural-acoustic performance.In this paper, based on the structural dynamic response function and acoustic radiation function, there have discussed the acoustic power sensitivity and structure-acoustic optimization problem. There have built the flow chart of structural-acoustic optimization, by integrating FEM code and BEM code, and the genetic algorithm is used as the strategy in MDO platform. In the optimization function, the acoustic radiation power is defined as objective function. In order to build the relational expression of pressure objective function and power objective function, the sphere enveloping surface model is introduced, with it to evaluate the pressure in acoustic domain.In the numerical example, there have deal with the sizing optimization, stiffeners layout optimization and topology optimization. In the sizing optimization, the stiffened plate in air and finite stiffened double cylindrical shell in water be analyzed. There have analyzed the double cylindrical shell by combining sensitivity information and Taylor formula. In the layout optimization, the stiffeners position is defined as design variable. In addition, there have a trial of applying the modification evolutionary structural optimization method in structural-acoustic topology optimization analysis.In the end, there have deal with the structural-acoustic optimization problem of submarine stern structure using MDO platform and power sensitivity information. After optimization, the acoustic performance is improved. The numerical analysis shows that use the acoustic radiation power as objective function is feasible and efficient.In this paper, some works have been done as fellow:(1) Using conformal transformation theory to analyze the acoustic radiation in a three-dimensional right-angle space, there have analyzed the influence of acoustic power and direction by the boundary property. The result has extended the space of acoustic boundary property.(2) Using the structural dynamic response function and acoustic radiation function, the sensitivity of acoustic radiation power is deduced. In addition, the sensitivity information is used to optimize the structural-acoustic radiation of stiffened double cylindrical shell and submarine structure.(3) Building the mathematical model of acoustic radiation optimization, using the MDO theory, there has analyzed the structural-acoustic optimization process and optimization platform.(4) Integrating FEM code and BEM code, the genetic algorithm is used as optimization strategy in sizing optimization, stiffeners layout optimization and topology optimization.更多还原