1988 年 74 巻 12 号 p. 2345-2352
A Statistical technique was used to clarify the difference between the bending strength of small size specimens and the crack initiation stress value of blast furnace hearth model constructed by carbon blocks.
By the Weibull's weakest link model, strength (size effect) and it's variance of carbon blocks of blast fur-nace hearth model were estimeted from those of small size bending specimen.
To obtain the crack initiation stress value of the carbon block, 2-dimensional elastic-creep analysis and 3-dimensional elastic analysis were carried out. The stress value which caused cracks in the carbon block model became about 1/51/4 of the bending strength of small size specimens.
Also, the variance of stress value was estimated from the variance of location of cracks in carbon blocks.
By combining the size effect, strength-and stress-value variances, we clarified that the stress level of about 1/51/4 of bending strength is small size specimens is large enough to cause cracks in large blocks of the blast furnace hearth model.