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71.
In this paper, we shall investigate the decay property of the solutions to the initial-boundary value problem for the elastic wave equation with a local time-dependent nonlinear damping. We give some decay rate of the energy when the damping term is effective only in a neighborhood of a suitable subset of the boundary. The results obtained in this paper extend, in particular, the known results for the scalar wave equation.  相似文献   
72.
This paper investigates the existence and uniqueness of solutions of some boundary value problems modeling the deformation of a membrane of revolution under a partially vanishing normal load. The frame of the membrane models we deal with is the Reissner theory of thin shells of revolution, in which strain-displacement relations are nonlinear, although it assumes a linear stress-strain relation.  相似文献   
73.
74.
We consider mixed finite elements for the plane elasticity system and the Stokes equation. For the unmodified Hellinger-Reissner formulation of elasticity in which the stress and displacement fields are the primary unknowns, we derive two new nonconforming mixed finite elements of triangle type. Both elements use piecewise rigid motions to approximate the displacement and piecewise polynomial functions to approximate the stress, where no vertex degrees of freedom are involved. The two stress finite element ...  相似文献   
75.
Conformational elasticity theory recently developed has been used to explore the internal energy contribution tothe elastic force f_e/f as a function of strain for poly(cis-1,4-isoprene) and poly(trans-1, 4-isoprene). Calculated f_e/f values arein good agreement with those obtained experimentally. Results show that behavior of f_e/f is mainly contributed by chemicalstructure, or intramolecular interaction, supporting the experimental observations, and that the internal energy contribution isstrain dependent.  相似文献   
76.
A three-dimensional, explicit and exact, equilibrium solution is derived for transversely isotropic, linearly elastic bodies in the form of a right cylinder simply supported over its lateral boundary and loaded over its end faces. This solution, which generalizes an earlier proposal of Levinson in various respects, is to serve as a benchmark for the corresponding plate theories. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
77.
Summary  The antiplane steady dynamic problem of the theory of elasticity for an isotropic layer and a half-layer weakened by tunnel cavities of arbitrary cross section is investigated. A radiating monochromatic shear wave (SH-wave) is considered as loading. Using the constructed Green's functions for a layer and a half- layer, the corresponding boundary problems are reduced to the Fredholm's integral equations of the second kind. The obtained algorithm is realized numerically by the quadrature method. Results specifying the influence of the openings configuration, their number and relative position, types of edge conditions and inertia effects on tangential stress concentration are given. Received 13 July 1999; accepted for publication 20 July 2000  相似文献   
78.
钱秀槟  陈皓明 《物理》2001,30(12):787-790
力调制显微术被用于观测铜基碳化硅样品,实验中发现在样品表面台阶边缘处出现一些异常信息。为此,文章作者通过测试一种表面同样有台阶但却是由同一种材料组成的样品来通信验证这些异常主要是由台阶的边界引起的,并对引起的异常作了半定量的估算。  相似文献   
79.
Fukuyama [Fukuyama, H., 2000. Returns to scale and scale elasticity in data envelopment analysis. European Journal of Operational Research 125, 93–112] provided some characterizations of scale elasticity and returns to scale in DEA. In this paper, we present some counterexamples and comments to the main lemma of the afore-mentioned paper, based on which Fukuyama’s idea has been built.  相似文献   
80.
Wave reflection in slightly compressible, finitely deformed elastic media   总被引:2,自引:0,他引:2  
Summary  In this paper, the reflection of a plane wave at an incrementally traction-free boundary of a half-space composed of nearly incompressible elastic material is considered. It is shown that two distinct cases exist, these being dependent on the underlying primary deformation. In the first case, the appropriate slowness sections are each approximately elliptical, and the corresponding reflection phenomena closely mirrors that associated with the corresponding linear isotropic theory. Specifically, an angular range of direction of incident wave exists, for which both a quasi-longitudinal and quasi-shear wave are reflected, the former being replaced by a surface wave outside this angular range. In the second case, the outer slowness section is re-enrant and, in addition to the scenarios previously mentioned, it is possible for two quasi-shear waves to be reflected. Numerical illustrations of reflection coefficients are presented in respect of a modified Varga material and the case of increasing bulk modulus is investigated. Received 17 January 2000; accepted for publication 22 February 2000  相似文献   
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