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131.
A modification of the material law associated with the well‐known Biot system as suggested by Murad and Cushman (Int. J. Eng. Sci. 1996; 34(3):313–338) and first investigated by Showalter (J. Math. Anal. Appl. 2000; 251(1):310–340) is reconsidered, generalized and analysed in the light of a new approach to a comprehensive class of evolutionary problems. The framework allows a uniform approach to problems involving general anisotropic, inhomogeneous, non‐smooth media thus covering, for example, transmission problems in layered materials. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
132.
随机需求弹性及在经济分析中的应用 总被引:9,自引:1,他引:8
引入随机弹性的概念及随机弹性的相关性质,进而给出随机需求弹性.利用随机需求弹性分析了当消费群体的收入为随机变量时,其收入对需求量的变化和影响.给出了当收入服从某种分布时,需求量的弹性分布. 相似文献
133.
带摩擦的弹性接触问题广义变分不等原理的简化证明 总被引:4,自引:0,他引:4
在弹性摩擦接触问题中 ,从变分原理出发来研究接触问题 ,可以将摩擦力纳入问题的能量泛函 .为了得到摩擦约束弹性接触问题的能量泛函 ,日前大多是用拉格朗日乘子法 ,但拉格朗日方法用在变分不等问题中 ,要利用非线性泛函分析和凸分析来证明 ,证明复杂 .本文利用向量分析的工具及巧妙的变换 ,对带摩擦约束的弹性接触问题的广义变分不等原理进行了严格的证明 ,由于只用到向量分析 ,简化了证明 . 相似文献
134.
Arkady I. Leonov 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2008,59(2):333-359
The paper develops a continuum theory of weak viscoelastic nematodynamics of Maxwell type. It can describe the molecular elasticity
effects in mono-domain flows of liquid crystalline polymers as well as the viscoelastic effects in suspensions of uniaxially
symmetric particles in polymer fluids. Along with viscoelastic and nematic kinematics, the theory employs a general form of
weakly elastic thermodynamic potential and the Leslie–Ericksen–Parodi type constitutive equations for viscous nematic liquids,
while ignoring inertia effects and the Frank (orientation) elasticity in liquid crystal polymers. In general case, even the
simplest Maxwell model has many basic parameters. Nevertheless, recently discovered algebraic properties of nematic operations
reveal a general structure of the theory and present it in a simple form. It is shown that the evolution equation for director
is also viscoelastic. An example of magnetization exemplifies the action of non-symmetric stresses. When the magnetic field
is absent, the theory is reduced to the symmetric, fluid mechanical case with relaxation properties for both the stress and
director. Our recent analyses of elastic and viscous soft deformation modes are also extended to the viscoelastic case. The
occurrence of possible soft modes minimizes both the free energy and dissipation, and also significantly decreases the number
of material parameters. In symmetric linear case, the theory is explicitly presented in terms of anisotropic linear memory
functionals. Several analytical results demonstrate a rich behavior predicted by the developed model for steady and unsteady
flows in simple shearing and simple elongation. 相似文献
135.
On the use of nickel foil strain gages at varying temperatures 总被引:1,自引:0,他引:1
When a strain gage made of nickel foil attached on the surface of a specimen is subjected to repeated loads, the elastic stress
is measured by observing slip-bands in the foil resulting from repeated strain. Calibration studies with rotating-bending
tests at various temperatures between room temperature and 350°C are performed on round steel bars with nickel foil. The relation
between the threshold stress for the first appearance of slip-bands and the number of stress cycles is examined at varying
temperatures, which provides the calibration values of the nickel foil tested at varying temperatures. Assuming that the first
appearance of slip-bands is based on the linear cumulative damage law, the calibration values at varying temperatures are
calculated from those established by the calibration tests at several constant temperatures. It is found that the calculated
calibration values agree well with the results obtained by the calibration tests at varying temperatures and that the calculation
applying the linear cumulative damage law is a useful method to presume the calibration values at varying temperatures without
performing the experiment. 相似文献
136.
A. E. Giannakopoulos K. P. Baxevanakis A. Gouldstone 《Archive of Applied Mechanics (Ingenieur Archiv)》2007,77(2-3):113-122
The present work gives a systematic and rigorous implementation of Volterra dislocations in ordinary two-dimensional finite
elements using the thermal analogue and the integral representation of dislocations through the stresses. The full fields
are given for edge dislocations in anisotropic crystals, and the Peach–Koehler forces are found for some important examples. 相似文献
137.
138.
For a linear anisotropic hyperelastic body subjected to a state of pure strain it is shown that there are at least three directions such that the stress and strain tensors are coaxial. 相似文献
139.
推出四个满足三维弹性力学基本方程的完备函数系,给出了用此函数系构造三维复杂区域边界加权残值试函数的一般原则,实例表明效果良好。 相似文献
140.
Equilibrium of a bar under uniaxial tension is considered as optimization problem of the total potential energy. Uniaxial
deformations are considered for a material with linear constitutive law of strain second gradient elasticity. Applying tension
on an elastic bar, necking is shown up in high strains. That means the axial strain forms two homogeneously deformed sections
in the ends of the bars and a section in the middle with high variable strain. The interactions of the intrinsic (material)
lengths with the non linear strain displacement relations develop critical states of bifurcation with continuous Fourier’s
spectrum. Critical conditions and post-critical deformations are defined with the help of multiple scales perturbation method.
An erratum to this article can be found at 相似文献