PSI - Issue 2_A

Loris Molent et al. / Procedia Structural Integrity 2 (2016) 3081–3089 Author name / Structural Integrity Procedia 00 (2016) 000–000

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is discussed in more detail in (Molent and Jones, 2015) where it is also shown that the various approaches that are commonly used to estimate the short crack da/dN versus ΔK curve can be represented by the Hartman-Schijve equation by allowing for small variations in  K thr . A more extensive range of examples, which includes the scatter seen in both long and short crack tests, on how scatter in crack growth tests can be captured by allowing for small variations in the term  K thr is presented in (Molent and Jones, 2015). 5. Conclusions This paper has discussed the equivalence of the Hartman-Schijve, the generalised Frost-Dugdale and fractal based crack growth equations. It has also provided examples of the utility of fractal based (derivatives and related) crack growth equations for application to aerospace components. These models have been found to be applicable to the physically short crack regime which is a primary region of interest in the design and sustainment of highly optimised metallic aircraft. References Barter S., Molent L., Goldsmith N., Jones R., 2005. An experimental evaluation of fatigue crack growth. Engng Fail Anal 12(1), 99-128. Bouchaud E., 1997. Scaling properties of cracks, J. Phys., Condens. Matter 9, 4319–4344. Carpinteri Al., 1994. Fractal nature of material microstructure and size effects on apparent mechanical properties. Mech Mater 1994;18,89-101 [Internal Report, Laboratory of Fracture Mechanics, Politecnico di Torino, N. 1/92; 1992]. Carpinteri An, Spagnoli A., 2004.A fractal analysis of size effect on fatigue crack growth. Int J Fatigue 26, 125–33. Carpinteri An., Spagnoli A., Vantadori S., 2010. A multifractal analysis of fatigue crack growth and its application to concrete. Eng Fract Mech 77(6), 974-984. Cherepanov GP, Balankin AS, Ivanova VS., 1995. 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