Issue 40

K. Kaklis et alii, Frattura ed Integrità Strutturale, 40 (2017) 1-17; DOI: 10.3221/IGF-ESIS.40.01 4 Figure 2: The geometrical definition of crack length * α (CCNBD) and α (CSTBD). By applying the Straight Through Crack Assumption (STCA) method [5, 14] to a CCNBD specimen, the relationships (3) and (4) take the form [10]:          * 1 0 I Ι * 0 P K Ν π R B a a a or     * I I P K Y π R B (5a) where       * * 1 0 I Ι * 0 Y Ν a a a (5b)          * 1 0 II ΙI * 0 P K Ν π R B a a a or     * II II P K Y π R B (6a) where       * * 1 0 II IΙ * 0 Y Ν a a a (6b) where * I Y and * II Y are the dimensionless stress intensity factors for CCNBD specimen. Clearly, * Y of CCNBD and Y of CSTBD are related by the following relationship:      * 1 0 * 0 Y Y a a a (7) The Eqs. (5) and (6) are employed to calculate fracture toughness values of CCNBD under mixed mode I-II loading. Atkinson et al. [4] provided a solution for Ι Ν and IΙ Ν given by a five-term approximation (for    0.1 0.6 ):           n 2i 2 I i i i 1 N T A θ (8)