Two billets of nuclear grade medium-grained semi-isotropic graphite were machined into rectangular 4-point bend and L-shaped specimens and tested to failure. The material was not irradiated. During the testing, as well as determining the failure load, the failure was monitored by a high speed camera. The results showed that: there was a difference in the failure loads both along a billet and between the billets, in the L-shaped specimens the cracks did not fail instantaneously but needed further movement of the testing machine's crosshead before total failure, and the speed of the crack varied in the different specimens. The data were analysed and it was found that the Weibull theory does not predict the failure well but fracture mechanics does provide a way of correlating the data, particularly the crack propagation.
Bibliographical noteFunding Information:
One of the authors (B.C.M.) would like to thank the Health and Safety Executive and the EPSRC for financial support. The views expressed in this paper are those of the authors and do not necessarily represent the views of the Health and Safety Executive.
The authors would also like to acknowledge the loan of the high speed camera from EPSRC, the support of Serco Assurance (formerly AEA Technology) and the supply of the graphite by UCAR/GrafTech.
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