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51.
52.
Tie-Jun Liu Yue-Sheng Wang Chuanzeng Zhang 《Archive of Applied Mechanics (Ingenieur Archiv)》2008,78(4):267-282
The main interest of this study is a new method to solve the axisymmetric frictionless contact problem of functionally graded
materials (FGMs). Based on the fact that an arbitrary curve can be approached by a series of continuous but piecewise linear
curves, the FGM is divided into a series of sub-layers with shear modulus varying linearly in each sub-layer and continuous
at the sub-interfaces. With this model, the axisymmetric frictionless contact problem of a functionally graded coated half-space
is investigated. By using the transfer matrix method and Hankel integral transform technique, the problem is reduced to a
Cauchy singular integral equation. The contact pressure, contact region and indentation are calculated for various indenters
by solving the equations numerically.
An erratum to this article can be found at 相似文献
53.
Using the multipoles method, we formulate the problems of radiation (both heave and sway) of water waves by a submerged sphere
in deep as well as in uniform finite depth water with an ice-cover, with the ice-cover being modelled as an elastic plate
of very small thickness. In each case this leads to an infinite system of linear equations which are solved numerically by
standard techniques. The added-mass and damping coefficients for a heaving and swaying sphere are obtained and depicted graphically
against the wave number for various values of the radius of the submerged sphere and flexural rigidity of the ice-cover to
show the effect of the presence of ice-cover on these quantities. When the flexural rigidity is taken to be zero, the numerical
results for the added-mass and damping coefficient for water with a free surface are recovered. 相似文献
54.
Alexander Linkov Liliana Rybarska-Rusinek 《Archive of Applied Mechanics (Ingenieur Archiv)》2008,78(10):821-831
The paper presents a general method to find asymptotics for a (multi-)wedge system containing a thin wedge. It employs separation
of the symmetric and anti-symmetric parts of the boundary displacements and tractions of the wedge. The method is applicable
when the angle of the thin wedge turns to zero. A physical interpretation of the derived equations is obtained by using power
expansions of non-polynomial functions, which appear after the Mellin transform. We establish that the first term in the expansion
of the symmetric part corresponds to shear, while the first term of the anti-symmetric part describes deflection of the wedge
axis. Numerical experiments, performed by using a code developed on the basis of the theory, show that using only the first
terms of the expansions insignificantly influence accuracy: the approximate results coincide with the exact values of roots
to the third significant digit even for the wedge angle of 30°. 相似文献
55.
A theoretical model for mid-and low-latitude ionospheric electric fields in realistic geomagnetic fields 总被引:1,自引:1,他引:0
The geomagnetic fields, which play important roles in the ionospheric dynamo, can greatly affect the global distribution of ionospheric electric fields, currents and other ionospheric electrodynamics phenomena. In the study of ionospheric electrodynamics phenomena, such as the longitudinal variations of ionospheric electric fields, the non-dipolar component of the geomagnetic fields must be taken into account. In this paper, we deduce a theoretical electric field model for ionospheric dynamo at mid- and low-latitude which adopt a modified magnetic apex coordinates system. In the new electric field model, the geomagnetic fields can be calculated from either the IGRF model or the dipole field model, and the neutral winds and conductivities are calculated based on empirical models. Then the dynamo equation for the electric potential is finally solved in terms of the line-by-line iteration method, and the ionospheric electric fields and currents are derived from the calculated potential. Our model can reproduce the main features of the ionospheric electrodynamics processes, so it will be a useful tool for the investigation of the upper atmosphere and ionosphere. 相似文献
56.
本文将物理系统层内进化扩展到世界经济系统中去,通过对世界经济循环结构与物理系统进化的层次结构关系的探讨,论述了世界经济周期的特征及经济周期的熨平作用。 相似文献
57.
张秉儒 《内蒙古大学学报(自然科学版)》2002,(4)
通过研究图的伴随多项式的因式分解 ,给出了证明非色唯一图的一种新方法 ,并且得到了若干图簇的色等价图的结构性质 相似文献
58.
59.
基于J2EE体系结构实现网上购物系统 总被引:5,自引:0,他引:5
J2 EE体系结构采用组件的思想 ,将业务逻辑层从客户、服务器端独立出来 ,从而带来开发、使用和维护的便利 .在分析的基础上 ,给出了一个网上购物系统的设计模型和实现方法 . 相似文献
60.
在总结现有诊断技术成功应用实例的基础上,提出了一种新的实用诊断原则-“最少试验故障模”原则,对于复杂的机械设备和系统,采用这种新的研究思路有利于降低研究难度,提高研究成果的实用性.还以滑动轴承为例,通过对滑动轴承主要失效形式和机理的分析,说明可将滑动轴承简化为-多输入(多种故障原因)-单输出(接触摩擦)的灰色系统模型,并以滑动轴承各种故障的共同特征-接触摩擦作为滑动轴承故障诊断研究的唯一故障基准模.根据上述研究思路,对静、动载荷工作条件下滑动轴承的故障诊断进行了大量的实验研究.实践表明,提出的诊断原则诊断效率高,实用性强,可借鉴用于许多领域的故障诊断. 相似文献