摘要:

It is known that internal pressure in rolls has an advantageous effect upon the fatigue life of the rolls. To investigate and optimize this effect, transient and steady-state temperature and thermal stress distributions were evaluated in rolls of metal rolling machines heated over the rolling region. The problem is formulated as that of a thick-walled hollow cylinder heated on its outer surface by a rotating source and subjected to an internal pressure. For long rolls two-dimensional analysis is performed and the temperature distribution is evaluated using the integral transform method. Thermal stresses are evaluated using the Airy's stress junction in conjunction with the thermoelastic displacement potential technique. The convergence and the numerical accuracy of the series solution is investigated. The results for the temperature distribution and thermal stresses given by the present method are in good agreement with those previously reported for the case of absence of internal pressure. This work is focused on establishing the dependence of the equivalent stress on the prestress condition, and numerical results are given for various values of the parameters involved. The pressure value that minimizes the total equivalent stress and the stress range, thus extending the fatigue life of the roll, is given for some cases of practical interest.

ISSN:0149-5739    

DOI:10.1080/01495739708956119

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Transient thermal stresses are an important consideration in production processes involving large temperature changes. Recently, thermal stresses have also become significant in design problems related to microelectronic devices through their effects on material properties and system parameters. To calculate the thermal stresses, three kinds of methods are available. The first is the analytical method, in which the elastic theory is used to find the exact solution. The second approach consists of some kind of approximate technique, such as a perturbation procedure. The third method is the use of a numerical process, such as a finite-difference or a finite-element method.

ISSN:0149-5739    

DOI:10.1080/01495739708956120

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The problem of distribution of thermal stresses and temperature is considered in a perfectly conducting half-space, in contact with a vacuum, permeated by an initial magnetic field when the bounding plane is suddenly heated to a constant temperature. The problem is in the context of generalized magnetothermoelasticity with one relaxation time. The solution is obtained using the method of potentials. Laplace transform techniques are used to derive the solution in the Laplace transform domain. The inversion process is carried out using asymptotic expansions valid for small values of time. Numerical computations for the temperature and stress distributions are carried out and represented graphically. A comparison is made with the results obtained in the absence of a magnetic field.

ISSN:0149-5739    

DOI:10.1080/01495739708956121

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

An approximate solution for the transient temperature field due to a neat flow uniformly distributed over the circular region on the surface of a connective half-space is given. The exact solution to the corresponding quasi-static thermoelasticity boundary value problem has been obtained on the basis of this solution. The influence of the Biot's and Fourier's numbers on the temperature field and the stress state has been traced

ISSN:0149-5739    

DOI:10.1080/01495739708956122

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The linear theory of thermoelasticity without energy dissipation for homogeneous and isotropic materials is used to study plane waves in a half-space. The waves are supposed to be caused by a time-dependent heating of the stressfree boundary, which includes (i) sudden heating to a constant temperature, (ii) smooth heating for all times, (iii) smooth heating followed by sudden cooling, and (iv) smooth heating that becomes constant after a lapse of time, among its particular cases. The Laplace transform method is used to solve the problem. Exact solutions, in closed form, for the displacement, temperature, and stress fields are obtained and analyzed. Numerical results that illustrate the theoretical analysis are presented

ISSN:0149-5739    

DOI:10.1080/01495739708956123

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor