Issue 43

F. Berto et alii, Frattura ed Integrità Strutturale, 43 (2018) 1-32; DOI: 10.3221/IGF-ESIS.43.01 8 The stress fields of three plates scaled in a geometrical proportion are shown in Fig. 7. In these plates the notch opening angle is kept constant and equal to 90°. The geometrical parameters of the base geometry ( a = t = 20 mm and W = 200 mm) are simultaneously multiplied or divided by a factor 100. The plots are drawn considering a plane at a distance of 2 mm from the surface for the base geometry ( z = 18 mm). This distance is increased or reduced according to the scale factor (= 100) in the other two cases. The increase or decrease of the in-plane shear stress components is according to the scale factor of (100) 0.0915 = 1.52. The variability of the out-of-plane shear stress components is much more pronounced, and according to the scale factor (100) 0.33 = 4.57. The intersection point between τ yz and τ yx stress fields varies from case to case: this point is located at 1 mm from the V-notch tip when a = 2000 mm, at 10 -2 mm when a = 20 mm and at 10 -4 mm when a = 0.20 mm. 1 10 100 1000 10000 100000 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01  yz [MPa]  xy [MPa] 2  thickness t=2000 mm notch depth a=2000 mm plate width W=20000 mm thickness t=20 mm notch depth a=20 mm plate width W=200 mm thickness t=0.2 mm notch depth a=0.2 mm plate width W=2 mm 1-  O =0.33 1.0 1-  2 =0.0915 1.0  0 =100 MPa Figure 7: Mode O and mode II stress fields for three models scaled in geometrial proportion. 10 100 1000 0.0001 0.001 0.01 0.1 1 10 K O [MPamm 0.33 ] K II [MPamm 0.0915 ] 2  thickness t=0.2 mm notch depth a=0.2 mm plate width W=2 mm thickness t=20 mm notch depth a=20 mm plate width W=200 mm thickness t=2000 mm notch depth a=2000 mm plate width W=20000 mm Figure 8: Notch stress intensità factors K II and K 0 for three plates scaled in geometrical proportion. The plots of the corresponding notch stress intensity factors, K O and K II , are shown in Fig. 8. These factors are determined on the notch bisector line according to the following expressions