Abstract: Cracked flattened Brazilian disk(CFBD) has the advantages to avoid the stress concentration of loading points, and to crack starting at the prefabricated crack tip, make it become one of the most commonly used specimens to study the fracture characteristic of brittle materials. A recent study found that T-stress can also affect the material fracture, but CFBD didn’t have an analytic formula of calculating T-stress. The finite element method combined with the analytical method is employed to systematically investigate the T-stress for the cracked flattened Brazilian disk under combined mode loading condition and systematically analyze the error and relative error．The calculation results show that within a certain range of load distribution angle, when the relative crack length is less than 0.65，the formula of the T-stress for the cracked Brazilian disk subjected to uniformly distributed pressure can be directly used to calculate the T-stress for the cracked flattened Brazilian disk under pure mode I, pure mode II and combined mode loading conditions．The relative error of T-stress increases with increasing of the relative crack length.

Key words: cracked flattened Brazilian disk( CFBD), T-stress, combined mode crack, numerical analysis