Non-uniform temperature gradients and thermal stresses produced by a moving heat flux applied on a hollow sphere

Abstract

This work presents numerical analyses of transient temperature and thermally-induced stress distributions in a hollow steel sphere heated by a moving uniform heat source applied on a certain zenithal segment (the heated zenithal segment, H ) of its outer surface (the processed surface) under stagnant ambient conditions. Along the process, the moving heat source (MHS) moves angularly from the first zenithal segment to the last zenithal segment on the processed surface with a constant angular speed, ω, and then returns backward to the first zenithal segment with the same speed. It is assumed that the inner surface is heat-isolated and that the outer surface except the heated segment is under stagnant ambient conditions. The numerical calculations are performed individually for a wide range of thermal conductivity, λ, of steel and for the different H s. The maximum effective thermal stress ratio calculated as per the heat flux intensity (q 0 ) can be reduced in considerable amounts. By increasing λ(∼ 75%) and ω(∼ 63%) the maximum effective thermal stress ratio calculated can be significantly reduced.

Three-dimensional finite element analysis of effects of roller intervals on tool forces and wall thickness in stagger spinning of thin-walled tube

“…Kenichiro et al 2 analyzed the hot shear spinning of cast aluminum alloy parts considered the thermal stress as a necessary process parameter. Yapici et al [3][4][5] studied the thermal stress distribution and variation produced by a moving heat flux applied on a hollow sphere, which provided an effective method for analyzing the thermal stress in spinning process, while the researchers of this article concentrate on the conventional tube spinning in which temperature of the material during the process is not very high and thermal stress has insignificant effects on the process results.…”

An experimental—numerical investigation of a metal spinning process

“…The previous works by the authors show the importance of considering these thermal effects [11][12][13]. In some works, which are especially applicable in the spinning process, a heat source is used instead of heat generated from plastic deformation and friction contact between tool and workpiece to handle thermal effects [14][15][16][17]. These works introduced an interesting approach in simulation of thermo-mechanical forming processes such as spinning process.…”

Three Dimensional Steady State Thermal Stress Analyses in a Clamped Solid Sphere

“…The solution of the Navier's equation without the body force for axisymmetric problems in the spherical coordinate system can be expressed [7][8][9], for example, by the Goodier's thermoelastic displacement potential f and the Boussinesq harmonic functions ϕ and Ψ ( Figure 5).…”