1995 年 13 巻 4 号 p. 619-627
This report summarizes the study on numerical analysis of thermal elastic-plastic deformations of steel pipes due to annular local heating process. This process in which while the local area is heated annularly the adjacent sections are cooled can be applied to reduce the diameter of steel pipes.
The results of this study are as follows ;
(1) While the circumferential plastic strains generated during heating period are compressive, they are tensile during cooling.
(2) When the compressive plastic strains remain after cooling, the pipe shrinks. The remaining tensile plastic strains cause the pipe to expand.
(3) The variation of the longitudinal temperature distribution controls whether the pipe shrinks or expands.
(4) Since the effect of the parameters on deformation of pipe, namely the distribution of temperature, the cross section shape of pipe and the number of themal cycles, can be determined by performing thermal elastic-plastic numerical analysis one can control the deformation of the pipe caused by a forementioned process.
(5) The numerical predictions show good agreement with experimental results. Moreover, it is found that the value of pipe shrinkage can be represented by the parameter αTmax/βLc.