摘要:

The properties of metal matrix composites subjected to mechanical and cyclic loading are investigated. It is demonstrated that the methods of Gokhfeld and Ponter that have been developed to determine the elasticfplastic response of mechanical structures can be extended to establish the effect of thermal loading on the behavior of metal matrix composites. The procedure makes use of the elastic solution for thermal cycle loading and limit load calculations.

ISSN:0149-5739    

DOI:10.1080/01495739208946130

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

We are interested in thermal stresses induced by cyclic temperature changes in inelastic structures. We indicate how, when using a special framework for the formulation of the global evolution of the structure, it is no more interesting to separate between the primary and secondary stresses and, moreover, how it is possible to give the useful answers for the design of a structure with the help of only clever purely elastic calculus.

ISSN:0149-5739    

DOI:10.1080/01495739208946131

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Bruno A. Boley was among the first to analyze thermally induced vibrations of beams and plates, a subject of paramount importance in various fields of engineering and space technology. The present paper is concerned with moderately thick plates within the Mindlin theory. A correspondence of the solution to the simpler one of an auxiliary prestressed thin plate with effective parameters is derived. By another projection the solution of the thermal deflection can be further reduced to that of two effectively stressed membranes. The correspondence of deflections is extended to moments and shear forces in the case of neglected rotatory inertia. The class of solutions, however, is restricted to simply supported plates with straight edge elements. The representation in the frequency domain is understood and frequency response functions for the deflection of parallogram plates are presented, where a Boundary Element Technique with Green's functions of rectangular domains is used.

ISSN:0149-5739    

DOI:10.1080/01495739208946132

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The effect of uniform thermal changes and mechanical loads on the inelastic response is described for certain two-phase materials of arbitrary phase geometry, and for two-phase fibrous systems of any geometry in the transverse plane. Auxiliary uniform strain fields are derived by superposition of the actual thermal field with a field caused by specific uniform overall stresses or strains. For many actual composite systems, the uniform fields are shown to be isotropic and thus capable of causing only elastic strains in a plastically incompressible matrix. This property permits an exact replacement of the actual thermomechanical loading path with a modified mechanical path. The modified path is utilized in derivation of many closed-form expressions for evaluation of the translation vectors for centers of overall yield and relaxation surfaces, instantaneous inelastic moduli, and plastic strains during thermomechanical deformation of the composite materials.

ISSN:0149-5739    

DOI:10.1080/01495739208946133

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A material parameter Rdis presented, called the “dynamic thermal shock resistance,” which measures the resistance to thermal stress waves induced by very rapid body heating, e.g. by radiation, of both slender and massive bodies. This dynamic parameter is the complementing counterpart to the well-known “quasi-static thermal shock resistance” Rs, which is the classical measure for the resistance to thermal stresses due to temperature gradients induced by ordinary contact (or surface) heating when inertia effects may be neglected. The two material parameters. Rdand Rs, give a very different ranking of materials. Both parameters have an important physical significance: they place a restriction, solely defined in terms of material properties, on the maximum value of the product of a characteristic structural dimension and the specific thermal power or heating.

ISSN:0149-5739    

DOI:10.1080/01495739208946134

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This paper presents a study of the stresses and temperatures developed in the region near the tip of the toot in the orthogonal machining problem. The flow field is approximated by that which exists in a perfect fluid that occupies the same spatial region as the work material and is studied by the conformal mapping technique. This mapping yieldx the flow lines and strain rates in parametric form. After the kinematics has been evaluated, the material is assumed to be a nonlinearly viscous substance that deforms along the same flow lines as those in a perfect fluid. Stresses and temperatures are calculated for the case of zero friction along the tool-work piece interface. Heating is due to the conversion of plastic work into heat and conduction is ignored. The case of zero rake angle is discussed in detail.

ISSN:0149-5739    

DOI:10.1080/01495739208946135

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This paper is concerned with thermoelastic material behavior whose constitutive response functions possess thermal features that are more general than in the usual classical thermoelasticity. After a general development of the constitutive equations in the context of both nonlinear and linear theories, attention is focused on the latter. In particular, the one-dimensional version of the equation for the determination of temperature in the linearized theory provides an easy comparative basis of its predictive capability: In one special case where the Fourier conductivity is dominant, the temperature equation reduces to the classical Fourier law of heat conduction, which does not permit the possibility of undamped thermal waves; however,'in another special case in which the effect of conductivity is negligible, the equation has undamped thermal wave solutions without energy dissipation.

ISSN:0149-5739    

DOI:10.1080/01495739208946136

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The evolution of contact pressure at the metal/mold interface in an idealized, directional solidification process is examined using a thermohypoelastic stress function and the Neumann temperature solution. Nonuniform thermal distortion of the casting is established through the application of an oscillatory temperature profile at the mold interface. This is an attempt to study the effects of the often highly irregular cooling profiles in typical industrial casting processes (albeit in an idealized fashion). In many of these processes, it is virtually impossible to cool the ingot uniformly due to a variety of process conditions. Nonuniform thermal distortion causes the contact pressure at the mold interface as well as the macroscopic freezing front morphology to oscillate. If the contact pressure exceeds the hydrostatic pressure of the residual molten metal to the point where its net value is zero, then an air gap is nucleated. This represents a condition in which the casting and the mold surfaces locally begin to separate. If air gaps nucleate beneath the thinnest sections of the undulating freezing front, then a condition of growth instability exists since further heat extraction beneath these regions is significantly reduced. The thickest regions of the casting continue to grow due to improved contact and hence the freezing front nonuniformities become significantly exaggerated with time.

ISSN:0149-5739    

DOI:10.1080/01495739208946137

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The stress and displacement fields in an elastic half space subjected to a circular cylindrical inclusion with uniform temperature distribution are investigated. Using the Green's functions for axisymmetric body farces in elastic half space, one closed form solution is obtained for both interior and exterior elastic fields of the inclusion.

ISSN:0149-5739    

DOI:10.1080/01495739208946138

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The steady-state thermally induced local effects in laminated composite materials are investigated from the micro- and macromechanical points of view. The micro-mechanical model is represented by the alternating layers of a perfectly bonded matrix-reinforcement system while the macromechanical counterpart is characterized by the effective thermal and mechanical properties of the constituent layers. The solutions are obtained within the framework of linear plane thermoelasticity via the Fourier transform technique and the flexibility/stiffness matrix method. As a numerical illustration, the micro- and macromechanical temperature and thermal stress fields due to given surface temperature distributions are presented to measure the degree of correspondence between the two models. Considerable discrepancies are observed to exist between the micro- and macromechanical thermal stress fields, especially, in regions involving high temperature gradients.

ISSN:0149-5739    

DOI:10.1080/01495739208946139

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor