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J.T.P de Castro et alii, Frattura ed Integrità Strutturale, 25 (2013) 79-86 ; DOI: 10.3221/IGF-ESIS.25.12 86 C ONCLUSIONS generalized El Haddad-Topper-Smith’s parameter was used to model the crack size dependence of the threshold stress intensity range for short cracks, as well as the behavior of non-propagating environmentally assisted cracks. This dependence was used to estimate the notch sensitivity factor q of shallow and of elongated notches, from studying the propagation behavior of short non-propagating cracks that may initiate from their tips. It was found that the notch sensitivity of elongated slits has a very strong dependence on the notch aspect ratio, defined by the ratio c/b of the semi-elliptical notch that approximates the slit shape having the same tip radius. These predictions were calculated by numerical routines. Based on this promising performance, a criterion to evaluate the influence of small or large surface flaws in fatigue and in environmentally assisted cracking problems was proposed. Such results indicate that notch sensitivity can indeed be properly treated as a mechanical problem. R EFERENCES [1] Peterson, R.E., Stress Concentration Factors, Wiley (1974). [2] Frost, N.E., Marsh, K.J., Pook, L.P., Metal Fatigue, Dover (1999). [3] Meggiolaro, M.A., Miranda, A.C.O., Castro, J.T.P., Short crack threshold estimates to predict notch sensitivity factors in fatigue, Int. J. Fatigue, 29 (2007) 2022–2031. [4] Wu, H., Imad, A., Nouredine, B., Castro, J.T.P., Meggiolaro, M.A., On the prediction of the residual fatigue life of cracked structures repaired by the stop-hole method, Int. J. Fatigue, 32 (2010) 670-677. [5] Castro, J.T.P., Meggiolaro, M.A., Miranda, A.C.O., Wu, H., Imad, A., Nouredine, B., Prediction of fatigue crack initiation lives at elongated notch roots using short crack concepts, Int. J. Fatigue, 42 (2012) 172-182. [6] Taylor, D., The Theory of Critical Distances: a New Perspective in Fracture Mechanics. Elsevier (2007). [7] Taylor, D., Geometrical effects in fatigue: a unifying theoretical model, Int. J. Fatigue, 21 (1999) 413–420. [8] Atzori, B., Lazzarin, P., Fillipi, S., Cracks and notches: analogies and differences of the relevant stress distributions and practical consequences in fatigue limit predictions, Int. J. Fatigue, 23 (2001) 355-362. [9] Atzori, B., Lazzarin, P., Meneghetti, G., A unified treatment of the mode I fatigue limit of components containing notches or defects, Int J Fracture, 133 (2005) 61-87. [10] Susmel, L., The theory of critical distances: a review of its applications in fatigue, Eng. Fract. Mechanics 75 (2008) 1706-1724. [11] Lawson, L., Chen, E.Y., Meshii, M., Near-threshold fatigue: a review. Int. J. Fatigue, 21 (1999) 15-34. [12] El Haddad, M.H., Topper, T.H., Smith, K.N., Prediction of non-propagating cracks. Eng. Fract. Mechanics, 11 (1979) 573-584. [13] Kitagawa, H., Takahashi, S., Applicability of fracture mechanics to very small crack or cracks in the early stage. Proceedings of the 2 nd International Conference on Mechanical Behavior of Materials. ASM (1976) 627-631. [14] Bazant, Z.P., Scaling of quasibrittle fracture: asymptotic analysis. Int. J. Fracture, 83 (1977) 19-40. [15] Tada, H., Paris, P. C., Irwin, G. R., The Stress Analysis of Cracks Handbook, Del Research (1985). [16] Castro, J.T.P., Leite, J.C.C., Does notch sensibility exist in environmentally assisted cracking (EAC)?, J. Mat. Research and Technology, in press, (2013). [17] Juvinall, R.C., Marshek, K.M., Fundamentals of Machine Component Design, 4 th ed., Wiley (2005). [18] Barsom, J.M., Rolfe, S.T., Fracture and Fatigue Control in Structures, 3 rd ed., ASTM (1999). A