Numerical analysis of an improved DCDC specimen for investigating mixed mode fracture in ceramic materials

Double cleavage drilled compression (DCDC) specimen, on account of its specific fracture parameters and also strong crack path stability, is frequently used in crack growth studies of brittle materials such as ceramics and glasses. Various configurations of this specimen have been developed and studied in the past in order to determine fracture parameters in different loading conditions. In this paper, an improved DCDC specimen is proposed by means of some geometrical modifications applied to the standard DCDC configuration. Finite element analyses indicate that contrary to all previous DCDC configurations, the new version has the distinct potential to provide the entire span of practical loading condition from pure mode I to pure mode II. It is also shown that the T-stress term is strongly negative in this specimen. Using a generalized maximum tangential stress (MTS) criterion, the T-stress effects on fracture initiation of the proposed specimen are investigated analytically. (C) 2009 Elsevier B.V. All rights reserved.