大直径薄壁箱体结构力学分析与精细优化设计

发布时间：2018-03-22 00:07

本文选题：过渡环　切入点：三心底　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：我国目前正在研制新一代运载火箭贮箱结构,未来还将研制重型运载火箭贮箱结构。随着结构尺度不断增加,结构尺寸效应更加明显,轻量化要求更高,传统的设计思路和方法已不能满足要求,在结构设计中需要更精细化的设计思路和量化控制手段。本文对大直径贮箱典型结构开展力学性能分析与优化设计,具体内容如下：1.针对某大直径贮箱Y形过渡环进行强度分析与精细优化设计。首先探讨过渡环与筒段焊缝连接处内外侧应力差过大的原因,然后研究Y形环和筒段形貌对焊缝及热影响区应力分布的影响规律。最后基于参数优化和形状优化的协同优化策略,利用ISIGHT多学科优化软件集成有限元分析软件ABAQUS搭建优化平台,基于该平台的最终优化结果可以有效地改善Y形环和筒段焊缝连接处的应力水平,提高贮箱的承载能力。2.针对大直径贮箱三心底的应力状态和内压稳定性进行研究。首先通过理论分析、有限元计算和试验测试探讨三心底的应力变化规律,并验证边缘应力是过渡区应力波动的主要原因。根据边缘应力的性质和特点,提出有效抑制边缘应力的具体措施。最后基于有限元分析软件ABAQUS,对受内压三心底进行弹、塑性屈曲分析,讨论屈曲行为对几何参数的敏感性,结果显示屈曲载荷和屈曲形态对几何参数比较敏感。3.针对大直径贮箱椭球底模数和内压稳定性进行研究。首先从理论上分析模数对椭球底应力、贮箱承载能力、箭体长度、贮箱重量及箱底与短壳间空间的影响规律。然后探讨筒段边界对椭球底屈曲载荷和临界屈曲模数的影响,结果显示筒段边界对椭球底内压屈曲行为存在抑制作用,筒段边界的存在导致箱底临界屈曲载荷较理论值偏大。最后研究典型椭球底结构对不同类型缺陷的敏感性规律,研究结果可为大直径贮箱椭球底内压屈曲折减因子的选取提供参考。4.针对大直径环形液氧贮箱进行力学性能分析与精细优化设计。对环形贮箱开展考虑稳定性约束的轻量化设计,基于拓扑优化技术获得内隔板最优传力路径,最终获得工程上可用的设计方案。
[Abstract]:At present, China is developing a new generation of carrier rocket tank structure, and will also develop a heavy launch vehicle tank structure in the future. With the increasing of structure scale, the size effect of structure is more obvious, and the requirement of lightweight is higher. The traditional design ideas and methods can not meet the requirements, and more detailed design ideas and quantitative control methods are needed in the structural design. In this paper, the mechanical performance analysis and optimization design of typical large diameter tank structures are carried out. The concrete contents are as follows: 1. The strength analysis and fine optimization design of the Y-shaped transition ring of a large diameter tank are carried out. Firstly, the reason for the excessive stress difference between the inner and outer side of the weld joint between the transition ring and the tube section is discussed. Then the influence of Y ring and tube shape on the stress distribution of weld and heat affected zone is studied. Finally, based on the cooperative optimization strategy of parameter optimization and shape optimization, The optimization platform is built by integrating the finite element analysis software ABAQUS with ISIGHT multidisciplinary optimization software. The final optimization results based on the platform can effectively improve the stress level at the joint of Y-ring and tube weld. The stress state and internal pressure stability of the three bottom of the large diameter tank are studied. Firstly, through theoretical analysis, finite element calculation and test test, the stress variation law of the three bottom is discussed. It is verified that the edge stress is the main reason for the stress fluctuation in the transition zone. According to the properties and characteristics of the edge stress, the concrete measures to effectively suppress the edge stress are put forward. Plastic buckling analysis is used to discuss the sensitivity of buckling behavior to geometric parameters. The results show that buckling load and buckling form are sensitive to geometric parameters. 3. The stability of modulus and internal pressure of ellipsoid of large diameter tank is studied. Firstly, the stress of modulus to ellipsoid, the carrying capacity of tank and the length of arrow are analyzed theoretically. The influence of the container weight and the space between the bottom of the container and the short shell on the buckling load and the critical buckling modulus of the ellipsoid is discussed. The results show that the boundary of the cylinder has an inhibitory effect on the buckling behavior of the ellipsoid bottom. The critical buckling load on the bottom of the box is larger than the theoretical value due to the existence of the boundary of the tube. Finally, the sensitivity of typical ellipsoidal structures to different types of defects is studied. The results can provide a reference for the selection of buckling factor in the ellipsoidal bottom of the large diameter tank. 4. The mechanical performance analysis and fine optimization design of the large diameter liquid oxygen tank are carried out. The stability of the ring tank is considered. Beam lightweight design, Based on the topology optimization technique, the optimal load transfer path of the inner diaphragm is obtained, and the design scheme available in engineering is obtained.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V421;V475.1

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