Issue 66

M. Sánchez et alii, Frattura ed Integrità Strutturale, 66 (2023) 322-338; DOI: 10.3221/IGF-ESIS.66.20

a

(8)

H=

R

c

+b

ρ

The parameters a and b represent the coefficients required for the fitting curve. In the context of the materials investigated in this study, the curve was fitted utilizing the least-squares methodology, considering a Poisson's ratio of 0.3. The resultant fitting parameters were determined to be 0.1896 and 0.3258 for U-notches, and 0.208 and 0.2982 for V-notches, as illustrated in Fig. 5.

Figure 5: Extrapolated values of the function H for ν =0.3 of a) U-notches and b) V-notches.

Figure 6: Example of calibration of W c and R c parameters with SENB specimens. When the material being analyzed does not have linear-elastic behavior, the application of the ASED criterion requires a calibration of the material ASED parameters, W c * and R c * (e.g. [14,24]), accounting for the material non-linearity. Then, the linear-elastic ASED criterion is applied to an equivalent linear-elastic material whose ASED parameters are those obtained from the calibration. The calibration performed here is based on the fracture loads of conventional fracture specimens (e.g., CT or SENB) containing U-notches with different notch radii. With the fracture loads of these two conditions (and the resulting maximum stresses at their corresponding notch tip, σ max1 and σ max2 ), the following conditions may be established:

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