Statistical Properties of Strengths of Graphites for High Temperature Gas-Cooled Reactor
1977 Volume 1977 Issue 89 Pages 48-54
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1977 Volume 1977 Issue 89 Pages 48-54
The statistical distribution of the tensile and bending strengths has been studied on the gilsocarbon isotorpic graphite (IM2-24) and the petroleum coke fine-grained isotropic graphite (7477PT) and the irradiation effect on the statistical nature of strength has also been studied on the former graphite.
As a result, the data of tensile and bending strengths can be well approximated by both the Weibull and the normal distributions.Both the Weibull modulus, m and the normalizing factor, σ0 in the Weibull statistics of strengths of irradiated graphite increased as compared with those for unirradiated one.The effect of specimen volume on strengths was not large as predicted by the Weibull theory.The experimental value of the bending to tensile strength ratio was larger than the calculated one based on the Weibull statistics.However, results based on the pseud-Weibull statistics, in which only the m value in the Weibull parameters m and σ0 is taken as the same value in the tensile and bending strengths, was comparatively consistent with the experimental value for 7477PT graphite.In conclusion, the weakest link model is considered to be able to apply approximate-ly but not exactly to the fracture of graphite.
