A crack propagation criterion based on Delta CTOD measured with 2D-digital image correlation technique

A. Ktari (1, 2) , M. Baccar (2) , M. Shah (2) , N. Haddar , H. F. Ayedi , Farhad Rezai-Aria (2)

1 ENIS - École Nationale d'Ingénieurs de Sfax | National School of Engineers of Sfax
2 ICA - Institut Clément Ader

The fatigue cracks growth rate of a forged HSLA steel (AISI 4130) was investigated using thin single edge notch tensile specimen to simulate the crack development on a diesel train crankshafts. The effect of load ratio, R, was investigated at room temperature. Fatigue fracture surfaces were examined by scanning electron microscopy. An approach based on the crack tip opening displacement range (Delta CTOD) was proposed as fatigue crack propagation criterion. Delta CTOD measurements were carried out using 2D-digital image correlation techniques. J-integral values were estimated using Delta CTOD. Under test conditions investigated, it was found that the use of Delta CTOD as a fatigue crack growth driving force parameter is relevant and could describe the crack propagation behaviour, under different load ratio R.

Mots clés: digital image correlation; crack propagation; forged steel; J-integral; CTOD

Domaines: Sciences de l'ingénieur [physics]

A. Ktari, M. Baccar, M. Shah, N. Haddar, H. F. Ayedi, et al.. A crack propagation criterion based on Delta CTOD measured with 2D-digital image correlation technique. Fatigue and Fracture of Engineering Materials and Structures, 2014, 37 (6), p. 682-694. ⟨10.1111/ffe.12153⟩. ⟨hal-01612001⟩