叠层连续开口圆柱壳的精确解

抛弃任何有关位移和应力模式的假设，引入δ-函数，对正变异性连续开口圆柱壳建立状态方程．给出薄的、中厚的和强厚的叠层连续开口圆柱壳静力问题的统一的精确解．数值结果和SAPS解进行了对比．     

正交各向异性位势问题边界元法中几乎奇异积分的解析算法

几乎奇异积分的计算困难阻碍了边界元法的工程应用。本文针对二维正交各向异性位势问题边界元法中近边界点的几乎奇异积分,采用分部积分法,导出一种直接的解析计算公式。该解析公式可以精确计算线性单元上的几乎奇异积分。对二次单元,可将其细分为几个线性元,采用该解析公式近似计算其边界积分。当内点离当前积分单元较远时,仍保持常规高斯数值积分模式;而当内点离其较近时,因常规高斯积分结果失效,则采用该解析积分取代高斯数值积分。数值算例证明了该算法的有效性和精确性。二次元计算结果比线性元计算结果更精确。     

The Exact Solution for Thick Laminated Cantilever Cylindrical Shell

ＴＨＥＥＸＡＣＴＳＯＬＵＴＩＯＮＦＯＲＴＨＩＣＫＬＡＭＩＮＡＴＥＤＣＡＮＴＩＬＥＶＥＲＣＹＬＩＮＤＢＩＣＡＬＳＨＥＬＬＦａｎＪｉａ－ｒａｎｇ（范家让）（ＤｅｐａｒｔｍｅｎｔｏｆＡｒｃｈｉｔｅｃｔｕｒａｌＥｎｇｉｎｅｅｒｉｎｇ，ＨｅｆｅｉＵｎｉｖｅｒｓ...     

Determining stress intensity factors in orthotropic composites from far-field measured temperatures

We demonstrate the ability to determine stress intensity factors in orthotropic materials directly from measured temperatures away from the crack and using far-field expressions for the stresses. This is advantageous, recognizing that recorded thermoelastic data can be very unreliable near the tip of a crack. In addition to singular terms that govern in the immediate vicinity of the crack tip, the present series expressions for the stresses contain higher-order finite terms. Little measured input information is needed and data acquisition positions can be selected largely at the user's discretion.     

The exact solution for thick laminated cantilever cylindrical shell

Discarding any assumption regarding displacement or stress models, the state equation for orthotropy is established in a cylindrical system. The exact solution is presented for the statics of thick closed laminated cantilever cylindrical shells. Every equation of elasticity can be satisfied and all the elastic constants are taken into account. Arbitrary precision of a desired order can be obtained. Project supported by the National Natural Science Foundation of China     

INFLUENCES OF ANISOTROPY ON BAND GAPS OF 2D PHONONIC CRYSTAL

Band gaps of 2D phononic crystal with orthotropic cylindrical fillers embedded in the isotropic host are studied in this paper. Two kinds of periodic structures, namely, the square lattice and the triangle lattice, are considered. For anisotropic phononic crystal, band gaps not only depend on the periodic lattice but also the angle between the symmetry axis of orthotropic material and that of the periodic structure. Rotating these cylindrical fillers makes the angle changing continuously; as a result, pass bands and forbidden bands of the phononic crystal are changed. The plane wave expansion method is used to reduce the band gap problem to an eigenvalue problem. The numerical example is given for YBCO/Epoxy composites. The location and the width of band gaps are estimated for different rotating angles. The influence of anisotropy on band gaps is discussed based on numerical results.     

正交各向异性复合井壁应力变形分析与应用

推出了正交各向异性多层复合井壁的应力、位移计算公式,分析了双层混凝 土中间夹泡沫塑料板的复合井壁的应力、变形规律. 发现当井壁环向弹性模 量小于径向弹性模量时,内壁最大剪应力和径向位移会随着环向模量的减小 而显著增大,若仍按各向同性设计,将可能出现病态井壁. 通过工程应用和现场测 试综合分析验证了上述结论,并提出了多层复合井壁破裂的新依据.     

A comparison on failure pressures of cylindrical pressure vessels

In this work, the failure pressures of thick and thin walled cylindrical pressure vessels considering the Voce hardening law and plastic orthotropy effect are obtained. The solution presented is used to compare the failure pressures of copper and brass cylindrical pressure vessels.     

Thermoelastic bending of locally heated orthotropic shells

The thermoelastic bending of locally heated orthotropic shells is studied using the classical theory of thermoelasticity of thin shallow orthotropic shells and the method of fundamental solutions. Linear distribution of temperature over thickness and the Newton’s law of cooling are assumed. Numerical analysis is carried out for orthotropic shells of arbitrary Gaussian curvature made of a strongly anisotropic material. The behavior of thermal forces and moments near the zone of local heating is studied for two areas of thermal effect: along a coordinate axis and along a circle of unit radius. Generalized conclusions are drawn __________ Translated from Prikladnaya Mekhanika, Vol. 43, No. 3, pp. 80–85, March 2007.     

Random Fiber Networks and Special Elastic Orthotropy of Paper

We consider a particular in-plane elastic orthotropy observed experimentally for various types of paper, namely: S ₁₁₁₁+S ₂₂₂₂−2S ₁₁₂₂=S ₁₂₁₂, where S _ijkm are components of the in-plane compliance tensor. This is a statement of the invariance of in-plane shear compliance S ₁₂₁₂, which has been observed in some studies but questioned in others. We present a possible explanation of this “special orthotropy” of paper, using an analysis in which paper is modeled as a quasi-planar random microstructure of interacting fiber-beams – a model especially well suited for low basis weight papers. First, it is shown analytically that without disorder a periodic fiber network fails the special orthotropy. Next, using a computational mechanics model, we demonstrate that two-scale geometric disorder in a fiber network is necessary to explain this orthotropy. Indeed, disordered networks with weak flocculation best satisfy this relationship. It is shown that no special angular distribution function of fibers is required, and that the uniform strain assumption should not be used. Finally, it follows from an analogy to the thermal conductivity problem that the kinematic boundary conditions, rather than the traction ones, lead quite rapidly to relatively scale-independent effective constitutive responses. This revised version was published online in July 2006 with corrections to the Cover Date.