摘要:

The influence of a preexisting flaw on the transient temperature distribution in a half-space is investigated numerically. The flaw, a Griffith crack parallel to the free surface, is nearly insulating in nature, thus perturbing the transient temperature distribution. For cracks within a crack length of the surface, it is shown that transient values of the stress intensity factors exceed the long-term asymptote.

ISSN:0149-5739    

DOI:10.1080/01495737908962386

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The time-dependent stress state in a representative element of a brittle fiber-reinforced linear viscoelastic material, caused by a constant temperature distribution in the cross section of the specimen, is considered. The thermo-viscoelastic stress analysis is performed by application of the correspondence principle of linear viscoelasticity to the associated thermoelastic problem. An example concerning a unit cell of a two-phase composite (silicon carbide fiber-reinforced aluminum matrix) is calculated. It may be shown that, owing to a reduction in the relaxation time of a viscoelastic material with rising temperature, the increased thermal stresses are reduced after a short time interval.

ISSN:0149-5739    

DOI:10.1080/01495737908962387

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Temperature changes in concrete frames induce forces and displacements in the frames. A general method of analysis, based on the minimization of total potential energy, is presented. In addition to the coefficient of thermal expansion, the response of a frame to temperature changes is sensitive to the bending stiffness of the flooring system and the effective modulus of elasticity of concrete. Recommendations are made on the selection of the effective coefficient of thermal expansion and modulus of elasticity of concrete, the effective width of slab in frame action, and the effective moment of inertia.

ISSN:0149-5739    

DOI:10.1080/01495737908962388

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The response of a circular viscoelastic plate to a transient temperature field varying along the radius and through the thickness is investigated. The plate, initially stress free at an elevated temperature, is suddenly placed in an environment with Newtonian cooling on all surfaces. The transient and residual stresses and displacements are analyzed. The material is assumed linear and thermorheologically simple, with the relaxation response approximated by Dirichlet series; inertia and thermomechanical-coupling effects are neglected. This leads to an efficient solution algorithm that eliminates the history storage requirements. The resulting coupled integrodifferential equations are solved at each time step by a superposition method. Numerical results for float glass, polymethyl methacrylate, and polyisobutylene are given.

ISSN:0149-5739    

DOI:10.1080/01495737908962389

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A general solution is given for the transient thermal stresses in a disk brake caused by constant heat generation on both plane surfaces. The solution rigorously meets the traction-free boundary condition on both the lateral and plane surfaces of the disk. Numerical results for the stress fields are given.

ISSN:0149-5739    

DOI:10.1080/01495737908962390

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Variational principles and Mutter's form of the entropy inequality are used to establish the balance laws and constitutive equations for thermorigid dielectrics. An isotropy integrity basis that depends on the polarization-gradient tensor, polarization vector, and temperature-gradient vector is constructed for the free-energy function, and its minimality is verified. Representations for the entropy-flux vector and the heat-flux vector, when substituted into the restrictions derived from the entropy inequality, lead to the conclusions that the coldness function A depends on polarization and that the commonly known relation for isotropic materials, according to which the entropy-flux vector is equal to the ratio of heat flux to temperature, is not valid for polarized materials.

ISSN:0149-5739    

DOI:10.1080/01495737908962391

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The temperature distribution during a steady axisymmetric extrusion process is calculated for a material with temperature-sensitive properties. Numerical results are obtained for Ti-6Al-4V. The extrusion process involves large deformations at high rates, and therefore large temperature changes are produced by the conversion of plastic work to heat. It is found that one must consider this adiabatic heating since temperature changes can easily be as large as 400°F. One cannot replace the temperature change with a uniform increase if one desires to calculate stresses.

ISSN:0149-5739    

DOI:10.1080/01495737908962392

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The main point of this sequence of three papers is the calculation of the temperature changes, due to the plastic working that occurs in extrusion and of the changes in the associated stress state. The general procedure for calculating the temperature distribution during steady axisymmetric extrusion was presented as Part 1 of the sequence. Numerical results are obtained herein for the case of Ti-6Al-4V for billets initially at 1400°F and 1750°F. The maximum temperatures turn out to be virtually the same, but local temperatures are substantially different. Part 3 will discuss the local stresses that occur during extrusion.

ISSN:0149-5739    

DOI:10.1080/01495737908962393

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

It is shown that the second law of thermodynamics induces uniqueness and continuous dependence upon initial-state and supply terms of smooth thermodynamic processes of thermoelastic fluids within the broader class of thermodynamic processes with shock waves.

ISSN:0149-5739    

DOI:10.1080/01495737908962394

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The Laplace transforms with respect to time of the governing equations of one-dimensional thermoelasticity are obtained, with the displacement and temperature fields coupled. Elimination of the Laplace transform of either field variable between the resulting linear, simultaneous, and coupled ordinary differential equations results in ordinary differential equations in the other field variable. The characteristic equations are identical for both variables. Depending on the sequence in which the elimination is carried out, the solutions are obtained in two different forms. The equivalence of these forms is established by using the properties of the characteristic roots. (This process provides an alternative to the state approach recently developed by the authors.) Applications to problems pertaining to a half-space and a layer of finite thickness are presented.

ISSN:0149-5739    

DOI:10.1080/01495737908962395

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor