轴对称胀形双曲金属薄壳非线性静力分析

对承受内压、非等厚轴对称双曲薄壳,基于大塑性变形几何关系,通过严格的数学推导,建立了用微分代数方程组描述的数学模型。避免了Gleyzal等建立的变形几何关系采用Taylor展开,导致求解大应变问题精度较低的不足。采用可变步长和变阶的Klopfenstein-Shampine数值微分方法进行计算,可方便地获得该类结构应力、应变和位移等参量的变化规律。通过对比该数学模型和基于Gleyzal几何关系数学模型的数值计算结果与试验结果,验证了模型能较好地描述胀形双曲金属薄壳的大应变特性。     

环形闭合薄壳的应力分析

本文对承受均布内压的环形闭合薄壳进行了应力分析，得出了纵截面上的正应力比横截面上的正应力大一倍的结论，并给出提高其强度的有效方法，具有实际意义。     

弹性薄壳的大变形分析

本文给出了弹性薄壳大变形时应变与位移之间的精确关系。经过合理的简化,给出了壳的挠度与厚度同级的大变形基本公式。当薄壳为柱形且作柱状弯曲时,精确地求得了壳的挠度与长度同级的大变形基本公式。这些公式符合实际和便于应用。用解析法求得了无限长园柱壳一边固定,另一边受力偶作用的精确解。用能量法求得了无限长条板的近似解。     

求解载流薄壳二维磁弹性的差分法

本文针对在电磁场和机械场耦合作用下的载流薄壳的非线性变形问题进行了研究。给出了载流薄壳在耦合场作用下的二维电动力学方程、磁弹性非线性运动方程和Lorentz力表达式,通过变量代换将描述载流薄壳的磁弹性状态方程整理成含有10个基本未知函数的标准Cauchy型。并通过差分法及准线性化方法,将标准Cauchy型非线性偏微分方程组,变换成为能够用正交离散法编程求解的准线性微分方程组,实现了载流薄壳的磁弹性应力与变形的数值解。     

开孔加筋碟形薄壳屈曲的工程分析方法

本文提出一种外压作用下开孔加筋碟形薄壳屈曲的近似分析方法──等价球壳方法。引入非球度影响系数反映环壳的影响，使用壳体当量膜厚度和当量弯曲厚度来描述筋条的影响，用名义应力和材料切线模量反映壳体进入塑性的程度。计算结果表明，本文所提方法具有较好的精度，可在一定范围内使用。     

管状陶瓷金属封接残余应力计算比较

陶瓷/金属封接过程中由于温差容易产生残余应力,将影响到封接强度和产品的可靠性.应用薄壳理论公式和ANSYS有限元分析软件对典型筒状陶瓷/金属对封结构的残余应力分布进行了计算比较,指出了薄壁理论公式的适用范同,同时讨论了异材界面端存在应力奇异性的问题.     

国产软铝材料硬化规律的研究

本文应用属薄膜试验研究了软铝塑性性应力应变关系，分析了软铝薄膜失稳时的应力和应变。     

玻璃钢容器椭圆形封头应变分析

本文以旋转薄膜理论为基础,论述了作为正交各向异性材料的玻璃钢容器半椭球形封头受轴对称均布载荷作用的应力分析和应变分析,以及椭球参数对封头应力、应变的影响。作者结合工程设计实践,建议选择长短半轴比为的√3椭球作为玻璃钢容器半椭球标准型封头。     

当今西方缆索及薄壳屋顶的发展

当今,世界上较大规模建筑的屋面通常采用薄壳和缆索屋面,这方面的技术,西方国家发展较早,而且比较成熟,我国则相对比较落后。本文介绍了二次大战后,西方国家缆萦及薄壳屋顶的发展。     

薄壳工程弹药聚能射流销毁技术

阐述了用聚能装药销毁薄壳工程弹药的设计原则,进行了射流销毁薄壳TNT和薄壳B炸药试验。利用有限元AUTODYN-2D程序对小尺寸聚能射流冲击起爆薄壳装药进行计算,分析了大炸高下对薄壳弹药的作用效果。结果表明,小尺寸聚能射流可以在一定炸高下销毁薄壳弹药但不产生强烈的爆轰或飞散破片。     

2×1200吨双臂架变幅式起重机臂架有限元计算

针对2×1200吨双臂架变幅式起重机臂架，用ANYS软件里的梁、板壳、多点约束单元等多种单元对臂架结构建立有限元模型，计算并分析了臂架结构在复杂工作环境及载额定载荷下的应力大小及分布状况，为臂架的结构设计及优化提供了理论依据。     

Mixed shell element for seven‐parameter formulation

A new mixed shell element is developed for a seven‐parameter formulation in this paper. The mixed shell element is constructed by assuming stress field and displacement field together. Assumed stress field and assumed displacement field can be combined by stress–strain relationship with Hu‐Washizu functional. The developed mixed shell element can provide more flexible stiffness than other commercial softwares. Additionally, seven‐parameter shell formulation is used instead of Reissner/Mindlin formulation, since it can provide the thickness change. Even though some commercial engineering software are not proper for very thick shell structure, the developed mixed shell element for seven‐parameter formulation can be used without distinction of thick shell and thin shell. An example of shell models with different thickness is provided with solid model. Static and modal analyses are also performed for verification. Copyright © 2005 John Wiley & Sons, Ltd.     

Adding transverse normal stresses to layered shell finite elements for the analysis of composite structures

This work presents a formulation developed to add capabilities for representing the through thickness distribution of the transverse normal stresses, σ_z, in first and higher order shear deformable shell elements within a finite element (FE) scheme. The formulation is developed within a displacement based shear deformation shell theory. Using the differential equilibrium equations for two-dimensional elasticity and the interlayer stress and strain continuity requirements, special treatment is developed for the transverse normal stresses, which are thus represented by a continuous piecewise cubic function. The implementation of this formulation requires only C⁰ continuity of the displacement functions regardless of whether it is added to a first or a higher order shell element. This makes the transverse normal stress treatment applicable to the most popular bilinear isoparametric 4-noded quadrilateral shell elements.

To assess the performance of the present approach it is included in the formulation of a recently developed third order shear deformable shell finite element. The element is added to the element library of the general nonlinear explicit dynamic FE code DYNA3D. Some illustrative problems are solved and results are presented and compared to other theoretical and numerical results.     

有限元法在42英寸多枪彩色显像管玻壳设计中的应用

由于多电子枪显象管玻壳是一个变厚度组合壳体 ,很难用板壳经典理论进行求解 ,所以在设计九电子枪彩管玻壳时用有限元方法预先知道该玻壳的应力分布。通过修改设计参数 ,使九电子枪彩管玻壳能满足强度要求。在设计玻屏时采用非均匀有理B样条的曲面分析方法 ,锥体采用四条组合的非均匀有理B样条曲线旋转一周得到。本设计实现了玻屏表面外形和曲率变化及玻壳结构设计的全参数化 ,提高了玻壳的设计效率。本文还给出了计算玻壳外型的公式和一些技术参数。计算机仿真结果表明 :4 2英寸九电子枪彩色无支撑CRT的玻壳既能满足强度要求 ,又具有好的视觉效果     

Non-linear buckling and postbuckling of shear deformable anisotropic laminated cylindrical shell subjected to varying external pressure loads

Non-linear buckling and postbuckling of a moderately thick anisotropic laminated cylindrical shell of finite length subjected to lateral pressure, hydrostatic pressure and external liquid pressure has been presented in the paper. The material of each layer of the shell is assumed to be linearly elastic, anisotropic and fiber-reinforced. The governing equations are based on a higher order shear deformation shell theory with von Kármán–Donnell-type of kinematic non-linearity and including the extension/twist, extension/flexural and flexural/twist couplings. The non-linear prebuckling deformations and initial geometric imperfections of the shell are both taken into account. A singular perturbation technique is employed to determine the buckling pressure and postbuckling equilibrium paths. The numerical illustrations concern the postbuckling response of perfect and imperfect, moderately thick, anisotropic laminated cylindrical shells with different values of shell parameters and stacking sequence. The results confirm that there exists a circumferential stress along with an associate shear stress when the shell is subjected to external pressure.     

改型等强度壳的理论与工程应用

提出一种新型连接结构:在相邻的两段不同直径圆柱壳之间嵌入一段"改型等强度壳",构成"柱-改型-柱"组合壳,使得两段不同直径的圆柱壳光顺地连接,可以大幅度降低结合部的局部弯曲应力。应用旋转壳有矩理论分析了这些组合壳的应力分布,对其工程应用——作为连接结构的"改型等强度壳"几何参数的选择提出了建议。     

复合材料旋转壳强度和稳定性有限元分析及实验研究

利用有限元方法对一种特殊形状的复合材料旋转壳在轴压工况和内压工况下的强度进行了计算分析,揭示了应力分布特点, 确定了破坏区域和方式, 预报了模型的破坏载荷值。同时对其在轴压、外压和轴/外压工况下的稳定性也进行了分析计算。对内压、轴压下的强度和轴/外压下的稳定性进行了实验研究。     

铸轧辊套热膨胀及热应力的有限元分析

本文在利用已有的有限差分法求解获得铸轧辊辊套温度场的基础上,采用有限元法分析了铸轧辊辊套相应的热变形和热应力。获得了热变形结果,以及在铸轧辊中产生的各种应力情况,其中第四强度理论的最大相当应力为703.7MPa,所得结果有助于解释辊套为何需采用用高强度钢材。