Comprehensive data for calculating the higher order terms of crack tip stress field in disk-type specimens under mixed mode loading

The aim of this paper is to determine the coefficients of singular, T-stress and third terms of crack tip stress field for two disk-type specimens under wide range combinations of mixed-mode I/II loading. The first specimen is a centrally cracked circular disk subjected to diametral load (CCCD sample) and the second one is a semi-circular disk under three-point bending (SCB sample). Using finite element method, the stress intensity factors K-I and K-II are calculated for two samples and then the state of pure mode II loading is expressed for each specimen. As an important parameter to predict the fracture toughness of quasi-brittle materials taking into account the geometry effect, the sign and magnitude of term A(3) are determined for both samples under pure mode I condition. It is found that the sign of A(3) is negative for any configurations of SCB sample under pure mode I while its sign for CCCD can be negative or positive corresponding to the ratio of a/R. (C) 2015 Elsevier Ltd. All rights reserved.