Solution of the Three-Dimensional Thermoelastic Problem in Stresses

A method is proposed for constructing a general solution to the three-dimensional thermoelastic equations in stresses (compatibility conditions and equilibrium equations). This general solution is valid for both an elastic half-space and an elastic layer. The second thermoelastic boundary-value problem for a half-space is studied in detail as an example     

On the Residual Stresses in the Vicinity of a Cylindrical Discontinuity in a Viscoelastoplastic Material

The one-dimensional deformation of a material and subsequent unloading in the vicinity of a single cylindrical discontinuity is calculated using the theory of large viscoelastoplastic strains. Emphasis is on the formation of a residual stress field during the loading-unloading process and the effect of the viscous properties of the material on the level and distribution of these stresses. A comparison is performed with results of solution of the corresponding problem using the theory of large elastoplastic strains. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 2, pp. 110–119, March–April, 2006.     

Stressed State in the Vicinity of a Hole in Mechanical Joint of Composite Parts

International Applied Mechanics - The stress concentration near holes in polymer composites is studied theoretically and experimentally. Based on finite element modeling, the stress concentration...     

Full-Field Thermoelastic Stress Analysis of a Finite Structure Containing an Irregularly-Shaped Hole

An assessment of the structural integrity of members containing irregularly-shaped cutouts necessitates knowing the associated stresses. Stress analysis of such structures can be challenging as theoretical solutions are seldom available for finite geometries having non-simple shaped discontinuities and, like numerical methods, they require accurate knowledge of external loads. The latter are often unavailable in practice. This paper describes the ability to process load induced temperature information with an Airy stress function in real polar coordinates to determine the stresses in an isotropic linear elastic finite tensile plate containing an irregularly-shaped hole. Using polar coordinates is significant in that while a relatively simple general solution to the governing biharmonic equation is available in polar coordinates, this is seemingly not so with orthogonal curvilinear coordinates. Compared with displacement-based experimental or finite element techniques, important advantages of the present technique include not having to differentiate recorded data, or know constitutive properties or external loads.     

热电材料孔边周期裂纹问题的热电弹分析

论文研究了均匀电流密度和能量流作用下,热电材料中带4k个周期径向裂纹的圆形孔口问题.考虑非渗透型电和热边界条件,运用复变函数理论和保形映射方法,得到了热电材料中电流密度、能量密度和应力场的精确解.依据断裂力学理论,运用Cauchy积分公式得到了周期裂纹的电流、能量和应力强度因子.数值结果分析了场强度因子随各个参数的变化...     

The Thermoelastic State of Orthotropic Shells Heated by Concentrated Heat Sources

A problem on thin-walled orthotropic shells of arbitrary Gaussian curvature acted upon by concentrated heat sources is solved by means of the two-dimensional Fourier transformation. The temperature is assumed to distribute linearly throughout the shell thickness. Convective heat exchange with the environment under Newton's law is taken into account. Calculated results are presented. The influence of the curvature on the thermoelastic state of various orthotropic shells is studied     

Determining Individual Stresses Throughout a Pinned Aluminum Joint by Reflective Photoelasticity

Pinned (bolted) joints are an extremely important, but difficult to analyze, structural or mechanical element. They are a class of inverse problems in which the stresses at the pin/hole interface are typically unknown. Moreover, stresses vary non-linearly with applied load. Failures of mechanical or structural systems frequently initiate at connections. Although almost always present, many stress analyses of such mechanical connections ignore friction for simplicity. The stresses are evaluated here in an aluminum connector using a series solution of an Airy stress function, the coefficients being evaluated from known boundary tractions (near, but not including the contact region on the hole) and photoelastically measured data obtained from a bonded birefringent coating. Both friction and pin/hole clearance are accounted for, and individual stresses are evaluated full-field, including on the contact boundary of the hole.     

A Dual Phase Lag Model on Thermoelastic Interaction in an Infinite Fiber-Reinforced Anisotropic Medium with a Circular Hole

The model of generalized thermoelasticity proposed by dual phase lag (DPL), is applied to study the thermoelastic interactions in an infinite fiber-reinforced anisotropic medium with a circular hole. A decaying with time thermal field on the boundary of the hole, which is stress free, causes the thermoelastic interactions. The solutions for displacement, temperature, and stresses are obtained with the help of the finite element procedure. The effects of the reinforcement on temperature, stress, and displacement are studied. The exact solution in the case of isotropic medium is discussed explicitly. The accuracy of the finite element method validated by comparing between the finite element and exact solutions for absence the reinforcement.     

集中载荷作用下各向异性平面内的椭圆孔或裂纹问题

应用复变函数Cauchy积分的方法,对含有椭圆孔或裂纹的各向异性平面,系统地导出了当其在面内受任意集中载荷作用时的复应力函数解或裂纹应力强度因子解析解,即基本解;并通过基本解的迭加,得到了在椭圆孔周或裂纹表面作用一般外载时的解,其特例证实了上述解的正确性。     

移动集中力作用下的局部脱空地基梁的振动

利用分离变量法导出了局部脱空地基梁在移动集中力作用下的振动解析解。通过应用例子讨论局部脱空地基梁振动的频幅特征,为分析和评估局部脱空地基梁的工程问题提供理论依据和手段。     

Determination of Interlaminar Stresses in Bending Problems for a Stack of Transversely Isotropic Plates

A mechanical and mathematical bending model for a stack of transversely isotropic plates is developed. The resolving equations for deflections and tangential displacements are supplemented with a system of differential equations for normal and tangential contact stresses. It is demonstrated that for stacks consisting of an arbitrary number of identical plates with no friction between them, the initial system of equations for contact stresses can be reduced to Helmholtz equations. This transition allows obtaining the complete eigenvalue spectrum for the Laplasian of the problem and, in special cases, eigenfunctions. They are Krylov functions when bending is cylindrical and Bessel functions when bending is axisymmetric     

集中载荷作用下具有光滑中心波纹膜片的非线性分析

波纹膜片是一种薄壳弹性体，由于它的参数很多，又相互制约，所以使得它的设计很复杂。在大多数位移式仪器仪表中，要求波纹膜片产生至少和膜片厚度是同样数量级的弹性位移。这就要求使用薄壳的几何非线性理论进行分析。大多数学者研究波纹膜片的弯曲问题，是采用扁壳理论讨论具有浅波纹的膜片。而工程实际中，经常遇到深波纹膜片，这就要求从一般壳体大挠度方程进行求解。本文采用轴对称旋转壳体的简化Re-issner方程。研究了在中心集中载荷作用下具有光滑中心波纹膜片的非线性弯曲问题。应用积分方程方法，可以获得膜片的特征关系（载荷-中心挠度关系）和应力分布。文末给出实例计算的数值结果。     

双向应力状态下三维球形空穴应力集中的实验研究

用光弹三维应力冻结切片法研究了双向应力状态下球穴附近应力分布和集中问题，介绍了含球穴的三维光弹性模型的尺寸确定、浇注工艺和实现双向应力状态及大面积均匀拉伸加载的方法，分析了在特定平面上的正应力σ，剪应力τ沿球穴边缘的分布及衰减规律。文中对实验数据进行了统计分析处理，证明了实验与理论结果符合一致     

双集中荷载下一次超静定梁的加载过程分析

对双集中荷载作用下一次超静定梁的弹塑性加载全过程进行了分析．根据变形特点可把加载过程分成四个阶段．第一阶段是常规的弹性阶段,第二阶段是固支端附近单个塑性变形区扩展的阶段,第三阶段是固支端和一个集中荷载附近两个塑性变形区同时扩展的阶段,第四阶段是固支端保持为塑性铰从而引起固支端附近区域卸载而梁中间的塑性变形区继续扩展直至形成第二个塑性铰的阶段．在第一阶段,弯矩内力和挠度与外荷载均是线性比例递增关系;在第二、第三两个阶段,弯矩和挠度与外荷载是不同的非线性关系;在第四阶段,弯矩与外荷载是非比例的线性关系,但挠度与外荷载却是复杂的非线性关系．给出了加载各阶段的弯矩及挠度计算公式,具有理论意义,也可供对应的结构设计应用．     

Analysis of the Influence of the Thickness and the Hole Radius on the Calibration Coefficients in the Hole-Drilling Method for the Determination of Non-uniform Residual Stresses

Experimental Mechanics - The Hole-Drilling method is a semi-destructive technique useful for obtaining residual stress distributions by drilling and measuring relieved strains. The standard for...     

Stresses in a bonded wafer

Several theoretical and experimental analyses of the stresses on the bonded interface of a loaded or heated bimaterial structure are reported. The results extend previous studies and illustrate the difficulties and limitations of stress analysis of a bonded interface.