摘要:

Rapid sliding rigid indentation with friction of a half-space is analyzed as a two-dimensional steady-state process governed by fully coupled thermoelasticity. While rapid sliding justifies an insulated contact zone, the half-space surface outside the zone is allowed to (i) exchange heat with the atmosphere via convection and (ii) have its convective properties altered by the sliding process itself. The problem boundary conditions are mixed in both mechanical and thermal fields, yet robust asymptotic forms are used to reduce analysis to a simply coupled integral equation set that exhibits both Abel and Cauchy operators. Exact solutions show that convection has no influence on contact zone extent, although other thermoelastic parameters do. The surface temperature, however, is both controlled by friction and influenced by convection; effects of the latter are even more pronounced far away from the indentor.

ISSN:0149-5739    

DOI:10.1080/014957399280634

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

The temperature and the stress fields in the solidified layer and in the mold of finite thickness for a unidirectional casting process are investigated. Earlier solutions are extended to include the effect of the thermal capacity of the mold on the freezing front growth instability. A numerical solution is obtained for both the heat conduction and the residual stress problem. The results show that the perturbation in contact pressure tends asymptotically to a maximum value at larger times for the lower values of the thermal capacities of the mold materials. The magnitude of the contact pressure perturbation is decreased by the inclusion of the thermal capacity of the mold material, and this effect is enhanced for less distortive and thicker molds. The present article assumes that the thermal and mechanical problems are uncoupled along the casting mold interface. Despite this limitation, the results presented in this article indicate that a mold with a higher thermal capacity (or lower thermal diffusivity) might be less susceptible to thermoelastic instabilities associated with the contact pressure and its dependence on the thermal contact resistance at the casting mold interface.

ISSN:0149-5739    

DOI:10.1080/014957399280643

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

Axisymmetrical thermoelastic singular stress problems for a nonhomogeneous infinite body and thick plate are considered, theoretically. It is assumed that the nonhomoge neous material properties of shear modulus of elasticity G, the coefficient of linear thermal expansion alpha, and the thermal conductivity lambda vary with the axial coordinate z according to the power product form. As an analytical model, a nonhomogeneous infinite body and thick plate with a penny-shaped crack subject to an arbitrarily distributed axisymmetrical heat supply on its crack surface are considered. The distributions of the displacement component and the stress component are analyzed using the fundamental equation system proposed in our previous paper, and the thermal stress intensity factor at a crack tip is evaluated theoretically. Numerical calculations are carried out for several cases taking into account the variety of nonhomogeneity of G, alpha, and lambda. Thereafter, the distributions of the displacements, stresses, and thermal stress intensity factor at the crack tip are shown graphically, and the influence of these nonhomogeneous material properties on the thermoelastic field and the thermal stress intensity factor is discussed.

ISSN:0149-5739    

DOI:10.1080/014957399280652

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

The governing system of equations of the dynamic one-dimensional linear thermoelas ticity is a composed hyperbolic-parabolic system and has been studied little in the literature. A Godunov-type numerical scheme for initial-boundary value problems is constructed. An energy inequality is used to control the stability of the proposed numerical scheme, which also allows us to classify thermoelastic problems in strongly coupled and weakly coupled problems. Most real materials fall into the weakly coupled case when the mechanical power can be neglected in the balance of energy equation. The proposed numerical scheme is used to test that the above property of the weakly coupled case and also to see if, in the strongly coupled case, the solutions of certain initial-boundary value problems show oscillatory behavior, which has certain similarities to those experimentally recorded at very low temperature and thought of as evidence of the existence of the "second sound."

ISSN:0149-5739    

DOI:10.1080/014957399280661

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

ISSN:0149-5739    

DOI:10.1080/014957399280670

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor