圆柱壳大开孔问题——单圆孔的理论解

从Ｄｏｎｎｅｌｌ圆柱壳方程出发，利用复变函数与保角映射的方法，将圆柱壳展开面上的开孔边界线保角晨射成单位圆，并在映射平面上给出了逼近大开孔圆柱壳方程解答的完备函数逼近序列，进而利用边界条件和正交函数展开的方法得到了自由孔边应力集中系数的表达式，最后，对具有开孔率的圆柱壳在不同荷载条件下的自由孔口边界上的应力集中的系数进行了计算，此种方法，同时研究圆柱壳开非圆大孔和接管等问题提供了可能性。     

Free vibration of composite laminated plate with complicated cutout

Abstract

This paper presents the free vibration analysis of a composite laminated square plate with complicated cutout. The problem formulation is based on the higher order shear deformation plate theory HDST C⁰ coupled with a curved quadrilateral p-element. The elements of the stiffness and mass matrices are calculated analytically. The curved edges are accurately represented using the blending function method. A calculation program is developed to determine the fundamental frequencies for different physical and mechanical parameters such as the cutout shape, plate thickness, fiber orientation angle, and boundary conditions. The results obtained show a good agreement with the available solutions in the literature. New results for the fundamentals frequencies of a composite laminated plate with complicated cutout are presented.     

圆柱壳开孔的应力分析

本文研究圆柱壳开孔附近的应力分析问题。由于开孔问题的边界形状较为复杂,使用圆柱壳的 Morley 方程进行求解较为困难。本文在进行误差分析的基础上提出修正 Mo-rley 方程,并给出适合于开孔问题边界的一般解。以圆柱壳受轴向拉伸和内压为例分析了开孔附近的应力分布。给出了开孔率为 1/2以下的开孔解,并对 Donnell 方程解的适用范围给予了新的评价。     

双向固定网格渐进结构优化方法

近年来发展的渐进结构优化方法是一种有前途的结构拓扑和形状优化方法.本文在渐进结构优化方法的框架内建立了统一敏感度的概念,并基于固定网格有限元技术,发展了一种新的增加材料技术,提出了双向固定网格渐进结构优化方法.将该方法应用于复合材料壳结构开孔形状优化,以孔周等Tsai-Hill强度值作为优化目标,可以得到合理的最优解,证明了双向固定网格渐进结构优化方法的适用性.不同的初始点能得到几乎相同的最优解,展示了本文方法良好的全局最优性.     

Flexural vibration analysis of an eccentric annular Mindlin plate

A weak-form quadrature element method is presented to study the flexural vibrations of an eccentric annular Mindlin plate. Typical combinations of boundary conditions are considered and the natural frequencies are obtained for both thin and moderately thick plates. All results are verified using the commercial computer code ANSYS. Excellent agreement is reached in all cases. Comparison of the present predictions with other available results for thin plates is also made.     

复合材料层合板开口补强选型分析

论文开展了受拉伸复合材料层合板圆形开口四种补强型式的研究.首先,基于Hoffman准则,分析补强型式对首层失效强度的影响,再通过比较开口周围最大应力和应变的降低程度,分析圆缺、环形、椭圆缺和矩形缺四种补强型式的补强效率.通过有限元参数化建模,分析了几何尺寸对补强效率的影响,给出了不同补强型式适合的补强范围.研究表明通过合理地设计补强型式可以有效地降低应力集中,提高拉伸破坏强度.分析结果可以为复合材料飞机结构在相似形状和载荷条件下的补强设计提供参考.     

小内力平板弹性波散射问题的摄动方法

基于平板小挠度弯曲波动方程,采用摄动方法具有纵向内力作用下的平板开孔弹性波的散射问题进行了研究,得么了传播稳态波时此种平板弯曲波动问题的分析解,分析了均匀纵向内力对弹性波散射结果的影响,作为算例,本文给出了平板圆形开孔的动应力集中系数的数值结果,并对计算结果进行了讨论。     

STRESS CONCENTRATIONS IN CYLINDRICAL SHELLS WITH LARGE OPENINGS

Based on Donnell's shallow shell equation, a new method is given in this paper to ana-lyze theoretical solutions of stress concentrations about cylindrical shells with large openings. With themethod of complex variable function, a series of conformal mapping functions are obtained from dif-ferent cutouts' boundary curves in the developed plane of a cylindrical shell to the unit circle. And,the general expressions for the equations of a cylindrical shell, including the solutions of stress concen-trations meeting the boundary conditions of the large openings' edges, are given in the mapping plane.Furthermore, by applying the orthogonal function expansion technique, the problem can be summa-rized into the solution of infinite algebraic equation series. Finally, numerical results are obtained forstress concentration factors at the cutout's edge with various opening's ratios and different loadingconditions. This new method, at the same time, gives a possibility to the research of cylindrical shellswith large non-circular openings or with nozzles.     

采用精确化理论求解厚板任意形开孔动应力集中

摘要：本文基于复变函数与保角映射法,采用平板弯曲振动精确化方程[9],对含任意形开孔平板中弹性波散射与动应力集中问题进行了研究。利用正交函数展开的方法将待解的问题归结为对一组无穷代数方程组的求解。作为算例,计算了自由边界条件下圆孔和椭圆孔的动弯矩集中系数的数值结果,并对板厚与孔径比对动弯矩分布的影响做了分析研究。结果表明：入射波数、平板厚度和椭圆偏心率等参数对动弯矩的分布都有很大的影响。在较低频率和平板较薄的情况下,基于文献[9]的方程与基于Mindlin板的动弯矩结果在数值分布上是基本一致的;在较高频率和平板较厚的情况下,基于文献[9]的方程与基于Mindlin板的动弯矩结果在数值分布计算结果相差较大。由于文献[9]给出的平板振动精确化方程是在没有任何工程假设条件下得到的,因此本文的分析计算结果更精确一些。     

The general solution for the stress problem of circular cylindrical shells with an arbitrary cutout

I.IntroductionIncircularcylindricaIsheIls.likeaircraftfuselages,deep-diving\-ehicles.pressurevesselsandoiIlines,openingsareinvariabl}'necessaryforavarietyoffunctionalrequirements.Stressconcentrationsonthecontourofcircularornon-circu1arcutoutsreducebearing…