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Analysis of Thermal Stress Failure of Segmented Thick‐Walled Refractory Structures
Author(s) -
CHANG W. S.,
KNIGHT C. E.,
HASSELMAN D. P. H.,
MITCHINER R. G.
Publication year - 1983
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1983.tb10534.x
Subject(s) - materials science , stress (linguistics) , composite material , thermal diffusivity , ultimate tensile strength , fracture (geology) , flow stress , thermal , magnitude (astronomy) , mechanics , strain rate , thermodynamics , physics , astronomy , philosophy , linguistics
A finite‐element analysis was conducted of the thermal stresses in rectangularly shaped components of segmented thick‐walled refractory structures with length in the direction of heat flow much larger than the height or width. Heating was assumed to occur uniformly at a linear rate over the front face defined by the smaller dimensions. Most calculations were carried out for two‐dimensional conditions of plane stress, which assumes that the magnitude of stress is independent of height. A limited number of three‐dimensional calculations permitted analyzing the effect of height. For moderate values of heating rates, corresponding to those possibly encountered in practice, a biaxial tensile stress was found to exist some distance behind the hot face with the maximum value of stress along the center‐line parallel to the component length, in accordance with the fracture mode observed in practice. At high heating rates, however, the maximum tensile stress component was found to occur parallel to the face being heated. For conditions of plane stress under moderate heating rates, the magnitude of stress was found to be proportional to heating rate and an inverse function of the thermal diffusivity. Maximum values of stress were encountered for intermediate values of width. This latter result suggests that the incidence of thermal stress failure may be reduced by either reductions or increases in the values of width commonly used in practice. The three‐dimensional calculations indicated that the magnitude of stress rises rapidly with height. This result suggests that improvements in thermal stress resistance can be obtained by reductions in the values of height from the current values in practice. By means of a fracture‐mechanical analysis it is demonstrated that cracks oriented perpendicularly to the direction of heat flow formed as the result of the above stresses could be unstable and are expected to propagate across the total cross section to lead to total separation, in accordance with observations. The stress values obtained in the present study were compared with those predicted by the Kienow theory. Reasonable agreement was found for the peak stresses at the lower values of time. However, with increasing duration and the higher values of height the Kienow theory underestimates the magnitude of stress considerably.