摘要:

The article is concerned with a linear theory for elastic materials with inner structure whose particles, in addition to the classical displacement and temperature fields, possess microtemperatures. In the first part of the article we derive an existence result for the dynamical theory and establish the continuous dependence of solutions on the initial data and body loads. Then we consider the equilibrium theory and present a uniqueness result and a solution for the field equations. The theory is illustrated with the solution of the problem of thermal stresses in an elastic space with a spherical cavity.

ISSN:0149-5739    

DOI:10.1080/014957300280407

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

The thermoelastic problem of uniform heat flow disturbed by a flat toroidal crack in a transversely isotropic medium is investigated using the method of Hankel transforms. The three-part mixed thermoelastic boundary conditions are satisfied using the tech niques of triple integral equations and multiplying factors. The stress intensity factors at the inner and outer crack tips are obtained in exact expressions as the products of a dimensional quantity and nondimensional functions. The fracture transition of a flat toroidal crack to a penny-shaped crack and to a two-dimensional line crack is studied at different values of the ratio of the inner crack radius to the outer crack radius.

ISSN:0149-5739    

DOI:10.1080/014957300280416

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

This article studies the thermal stresses and the effective thermoelastic properties of composites containing ellipsoidal inhomogeneities. The cluster scheme developed recently by A. Molinari and M. El Mouden in The Problem of Elastic Inclusions at Finite Concentration,Int. J. Solids Struct, vol. 33, pp. 3131 - 3150, 1996, for the case of elastic inclusions embedded in an isotropic elastic matrix, is generalized to the case of ellipsoidal thermoelastic inclusions embedded in an anisotropic thermoelastic matrix. The shape, spatial distribution, and orientation of the inhomogeneities are taken into account in our scheme. The theoretical results for a composite ofSiO2particles in a Kerimid matrix are in good agreement with experimental measurements.

ISSN:0149-5739    

DOI:10.1080/014957300280425

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

In this article, a genetic algorithm is applied to an optimization problem of material composition for a plate of step-formed functionally graded materials. The step-formed functionally graded plate is analyzed as a laminated composite plate made of numerous layers with homogeneous and different isotropic material properties. First, the onedimensional transient temperature distribution for a laminated plate is analyzed theoret ically. In addition, the thermal stress components for such an infinitely long plate are formulated under the mechanical condition of being traction-free. As a numerical example, a plate composed of zirconium oxide and titanium alloy is considered. In addition, for the optimization problem of minimizing the thermal stress distribution, the numerical calculations are made using a genetic algorithm without supposing a distribution function of material composition and the optimal material composition of each layer is determined taking into account the effect of the temperature dependency of material properties. Furthermore, the results obtained when a distribution function isn't specified and the results found when a distribution function is specified are compared.

ISSN:0149-5739    

DOI:10.1080/014957300280434

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

In a mathematical modeling of the physical behavior of a hygrothermoelastic medium, a moisture field vector and a thermal field vector are introduced, Hamilton's principle is stated, and a three-field variational principle is derived. The differential variational principle is shown, as Euler - Lagrange equations, to generate the divergence equations and the associated natural boundary conditions of a hygrothermoelastic medium. This variational principle is augmented through an involutory transformation in order to incorporate the gradient equations and the constitutive relations of an anisotropic hygrothermoelastic medium; hence, a ten-field variational principle is formulated and some of its special versions recorded.

ISSN:0149-5739    

DOI:10.1080/014957300280443

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

Small crack kinking in functionally graded materials (FGMs) subjected to a constant initial strain resulting from stress relaxation is studied. The FGMs are modeled as simply nonhomogeneous materials; that is, the effect of microstructure is neglected and the material property variation is considered to be continuous. The material gradation in the FGMs is taken to be of a power-law type. Systematic finite element calculations are made for the energy release rate of the crack. With regard to the local homogeneity, the toughness is taken to be independent of direction; therefore, the crack propagates along the direction of the maximum energy release rate. It is shown that the crack length and the thickness of the surface zone subjected to the initial strain have a strong effect on the kink direction, whereas the material gradients have little effect.

ISSN:0149-5739    

DOI:10.1080/014957300280452

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

ISSN:0149-5739    

DOI:10.1080/014957300280461

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor