Issue 33

R.C.O. Góes et alii, Frattura ed Integrità Strutturale, 33 (2015) 89-96; DOI: 10.3221/IGF-ESIS.33.12 91 modulus, a typical value for steels. The models were built with symmetry with respect to the xy plane at the plate mid- thickness and to the xz plane. The EH models received additional symmetry with respect to the yz plane. The uniform load is applied in the model as a uniform tensile stress on the upper plate face y  H . The notch tip region is described by structured meshes with a maximum element size of 0.1  at the notch tip, where   b 2 /a is the notch tip radius. The dimensions of the analyzed notches are listed in Tab. 1. notch b/a  /a B/  elliptical 1 1 0.1, 0.2, 0.4, 0.6, 1, 1.5, 2, 3, 4, 6, 8, 10, 20 0.5 0.25 0.4, 0.8, 2, 2.8, 4, 6, 8, 12, 16, 32, 48 0.2 0.04 3, 6, 10, 15, 20, 30, 50, 75, 100 0.1 0.01 0.4, 0.6, 1, 2, 4, 6, 10, 20, 40, 60, 100 semi- elliptical 1 1 0.2, 0.3, 0.5, 0.7, 1, 2, 3, 5, 7, 10, 20, 30 0.5 0.25 0.16, 0.24, 0.4, 0.8, 2, 4, 8, 12, 16 0.2 0.04 0.5, 1, 3, 10, 20, 30 0.1 0.01 0.6, 6, 10, 20, 40, 60, 100, 200, 400 Table 1 : Elliptical and semi-elliptical notch parameters analyzed in the present FE models. Figure 1 : K  /K t distribution along the notch tip front, for a large plate with an elliptical hole with b/a = 0.5 and  /a = 0.25 . Figure 2 : K  /K t distribution along the notch tip front, for a large plate with an elliptical hole with b/a = 0.5 and  /a = 0.25 . Fig. 1-2 shows typical K  / K t and K  / K t distributions along the notch tips of EH with b/a  0.5 and  /a  0.25 . Note that K   K  , and that their maximum values occur close to the surface of thick plates (with B >>  ), whereas for thinner plates they occur at the plate center. K  / K t ratios depend on B/  , see Fig. 3. For relatively blunt notches (those with low B/  ratios), the maximum values of the stresses and strains along the notch tip  max and ε max occur on the middle plane of the plate, but for sharper notches these values dislocate towards the plate free surfaces (located at z/B  0.5 ), in a slightly decoupled way. K  and K  can differ up to 15% in such plates. The maximum SCF at the notch tip K  max can be up to about 8% higher than the 2D SCF K t , a non-negligible difference. Therefore, even experimental K t values, measured as usual at the notched component free surfaces, may underestimate the actual value of  max at such notch tips, so 3D effects on stress/strain fields along notch tips may indeed be relevant for some practical applications.