Modeling the ductile-brittle failure mode transition in rock cutting

Rock cutting represents a class of problems that exhibits ductile-brittle failure mode transition. Using the depth of cut as a structure size measure, this transition has been shown to follow Bazant's simple size effect law for quasibrittle material. This study showed that the finite element analysis with the adoption of a continuum damage material model could capture the ductile-brittle transition in rock cutting, and produced the size effect law. One of the major defining characteristics of rock cutting modeling is that no pre-existing notches were introduced, and that the crack grow path was not known a priori. The trend of how nominal stress-relative displacement varied with sizes was found similar to those of notched plates under simple tension or three point bending tests. That might imply a common response feature for mechanisms that satisfy the simple size effect law. (C) 2014 Elsevier Ltd. All rights reserved.