A failure model for nuclear graphite is presented in the context of continuum damage mechanics. It relates tractions to the relative displacements at an interface where cracking may occur. Both the stress-based and fracture-mechanics-based failure criteria are included in the model to construct a damage surface which shrinks in the stress space as damage develops. Damage initiation is governed by the stress criterion and full formation of a crack by the fracture-mechanics criterion. The unified failure model can deal with failure under both regular and singular stress concentration conditions. Numerical predictions for tension of L-shape and channel-section graphite specimens of different corner radius, including sharp corner, have been performed. The predicted failure loads are in good agreement with available experimental data. This indicates that the present failure model is suitable for graphite material.
Bibliographical noteFunding Information:
The financial support of the Health and Safety Executive through contract NUC/56/60/5 is gratefully acknowledged. The authors are also grateful to B.C. Mitchell and J. Smart for providing their experimental data for comparison. The views expressed in this paper are those of the author(s) and do not necessarily represent the views of the Health and Safety Commission/Executive.
Copyright 2008 Elsevier B.V., All rights reserved.