PSI - Issue 39

Jesús Toribio et al. / Procedia Structural Integrity 39 (2022) 470–474 Author name / Procedia Structural Integrity 00 (2021) 000–000

474

5

0.0 5.0 10 -8 1.0 10 -7 1.5 10 -7 2.0 10 -7 2.5 10 -7 3.0 10 -7 3.5 10 -7

( /cycle)

da/dN (m/ciclo)

0

15

30

45

0 (º)

α

Fig. 4. Fatigue crack growth rate as a function of the deflection angle of the kink.

4. Conclusions The following conclusions may be drawn about the effect produced by the near-tip fatigue crack path deflection on the plasticity-induced fatigue crack growth: (i) The fatigue crack growth rate was calculated for both configurations of uniaxial fatigue (only the main crack) and locally-multiaxial fatigue (main crack plus deflected kink). (ii) Cracks with a near-tip deflected kink in a plate subjected to remote mode I (opening) fatigue tensile loading exhibit plastic crack advance tending towards a global mode I (in spite of the local mixed mode). (iii) The near-tip crack path deflection produces a retardation effect on the fatigue crack growth when compared with a fully straight crack (with no kink). (iv) The deflection-induced fatigue crack growth retardation effect increases with the initial angle of the deflected near-tip kink . References Kitagawa, H., Yuuki, R., Ohira, T., 1975. Crack-morphological aspects in fracture mechanics. Engineering Fracture Mechanics 7, 515–529. Suresh, S., 1983. Crack deflection: implications for the growth of long and short fatigue cracks. Metallurgical and Materials Transactions 14A, 2375–2385. Toribio, J., Kharin, V., 2013. Simulations of fatigue crack growth by blunting–re-sharpening: Plasticity induced crack closure vs. alternative controlling variables. International Journal of Fatigue 50, 72–82. Toribio, J., Matos, J.C., González, B., 2014. A macro- and micro-approach to the anisotropic fatigue behaviour of hot-rolled and cold-drawn pearlitic steel. Engineering Fracture Mechanics 123, 70–76. Tvergaard, V., 2004. On fatigue crack growth in ductile materials by crack–tip blunting. Journal of the Mechanics and Physics of Solids 52, 2149– 2166. Handerhan, K.J., Garrison Jr., W.M., 1992. A study of crack tip blunting and the influence of blunting behavior on the fracture toughness of ultra high strength steels. Acta Metallurgica et Materialia 40, 1337–1355.