A systematic investigation of T-stresses for a variety of center-cracked tension specimens

• T-stresses for CCT specimens with various crack lengths and thicknesses were obtained.
• T11 and T33 were negative for all of the CCT specimens studied in this work.
• Both T11 and T33 changed significantly for the ASTM E2472 standard CCT specimens.

In this work, a systematic investigation of three-dimensional (3D) T-stresses (T11 and T33) was conducted using detailed elastic finite element analysis (FEA). The interaction integral method was applied to extract the T-stress solutions. Standard CCT specimens with a thickness-to-width ratio of B/(2W) ⩽ 0.0625 and a crack length-to-width ratio of a/W = 0.25–0.7, as specified in ASTM E2472, were considered, and the cases of B/(2W) = 0.1–1.0 and a/W = 0.05–0.2 and 0.8 were also added. From the FEA results, it was found that both T11 and T33 at the specimen mid-plane showed significant changes with crack lengths and specimen thicknesses for those CCT configurations that satisfy ASTM E2472. Because both the in-plane and out-of-plane T-stresses were negative and showed large variations for all the considered CCT specimens which was true even for the CCT specimens complying with the ASTM E2472 standard, it was noted that these CCT specimens that complying with the standard might show the test specimen size effect (including the crack length and specimen thickness effect) on the fracture toughness if tested.