【作者】 王云；

【导师】 唐国金；

【作者基本信息】 国防科学技术大学 ， 航空宇航科学与技术， 2007， 硕士

【摘要】 结构完整性是固体发动机设计的重要指标。理论和经验表明,通过对发动机药柱的几何构型和材料参数优化,可以极大地改善发动机的结构完整性能。本文从结构优化的基本原理和方法出发,对工程中广泛使用的管形和星形药柱构型、斜槽和伞盘等典型几何特征,以及发动机各部件的材料参数进行了灵敏度分析与优化研究。本文主要内容如下:介绍了固体发动机结构完整性分析的相关概念和发展历程,探讨了结构优化的产生背景和发展现状,对本文研究的软件平台MSC.Nastran做了简单介绍。论述了结构优化的理论基础和一般方法。作为结构优化的基础,推导了有限单元法的基本方程以及其数值求解方法。介绍了用于结构优化的近似模型的概念和处理方法,探讨了用近似模型对结构进行优化算法的过程,并介绍了约束筛选、灵敏度分析等相关概念。利用MSC.Nastran的结构优化功能,对管形和星形两种典型药型进行了灵敏度分析和优化处理。讨论了形状优化中位移模式的作用及其建立的方法,对辅助模型做了重点介绍。根据固体发动机的结构和受力特点,建立了管形和星形两种药型的平面应变模型,对其进行了结构完整性分析,并对两种药型的控制参数进行了灵敏度分析,在此基础上讨论了它们的优化设计方法。讨论了斜槽、伞盘和人工脱粘层等三种典型几何特征对发动机结构完整性的影响。尽管固体发动机在长度方向的特征结构对结构完整性的影响,远没有平面模型控制参数来得明显,但通常这些几何特征是发动机的主体结构之一,有可能会对发动机结构完整性造成相当大的局部影响。对这些结构进行结构完整性分析和灵敏度分析,可以确定其最佳设计参数。探讨了各向同性和正交各向异性材料在固体发动机中应用的可能性。分别采用各向同性和正交各向异性材料对固体发动机的推进剂、绝热层和壳体材料的各参数灵敏度进行了分析。随后建立了关于材料的理想发动机模型,对发动机各部件的材料进行了优化分析。本文的研究成果对固体发动机的结构完整性分析和优化设计具有重要的指导作用,其中的方法和结论可供发动机设计、制造和使用部门参考。更多还原

【Abstract】 Structural integrity is one of the vital criteria for Solid Rocket Motor (SRM) design. It is shown that, the optimization of grain shapes and material properties could greatly improve the structural integrity of SRM. In this paper, the basic discipline and method of structural optimization are discussed, several grain models and geometric features are studied, and also, the material properties are optimized.The main achievements are summarized as follows:The conspectus on SRM structural integrity is put out firstly. The significance, history, status and correlative concepts are introduced. And the overview of structural optimization is also outlined, besides the software platform, MSC.Nastran.Basic theory and methods of structural optimization are discussed detailedly. Finite Element Method is addressed as a main solution to the structural analysis. The approximation model, built up on analysis results, referred by optimization direction and depth search, is investigated concretely. And some arithmetic are presented also, including constrain screening, convergence detection, sensitivity analysis, and so on.The two grain shapes, the tube and the star, are researched. Owing to particularity of shape optimization, the Basis Vector, which would guide the optimization procedure, is introduced. And the auxiliary models, which to help generate Basis Vectors, are also conducted. Considering the characteristic of SRM and its loads conditions, the plain-strain models of the tube and the star, are built up respectively. Each of them is analyzed under complex loads and boundary conditions. Several sensitivity factors of the shape parameters are studied emphatically, and the optimal schemes are discussed later.SRM containing slopeing groove, umbrella slot or debonded release boot is investigated. Although length geometric features do not have obvious influence on structural integrity as the plain figures, the three are usually of main bulk structure, and often have sharp influences on local structural integrity. In order to determine their optimal shapes, some structural ananlysis and sensitivy analysis are carried out.The possibility of application of isotropic and orthotropic materials on SRM is studied. The main components of SRM, propellant grain, insulation and case are equipped with isotropic and orthotropic materails respectively. The structural and sensitivity analysis are performed to each modulus of any component materials. And the ideal model about materials is promoted out, discussing the utility and availability of various materials on SRM.The achievements obtained in this dissertation provide an important guidance to the structural integrity analysis and optimization design on SRM. The methods and conclusions would be available for the designers, manufactures and users of SRM._____更多还原