Initiation of Failure in a Radially End-constrained Circular Cylinder of Brittle Rock.
Internat J Rock Mech and Min Sci 8:371-387
Results are presented of a Bureau of Mines study of the effect on the fracture initiation stress of loading a cylindrical specimen of brittle rock between steel end-plates with a diameter either equal to or slightly larger than the specimen diameter. The effect on fracture initiation stress of interposing a low-modulus insert material between the specimen and end-plates is discussed. In this paper, fracture initiation stress is defined to be the stress required to initiate microcracking (void growth) in the rock specimen. The three-dimensional axisymmetric finite-element method of solution is used to calculate the stress distribution in the specimen when a constant displacement is applied over the surface of the end-plates. These results are then used to calculate the fracture initiation stresses.
Internat. J. Rock Mech. and Min. Sci., V. 8, PP. 371-387