Issue 46

A. Baltach et alii, Frattura ed Integrità Strutturale, 46 (2018) 252-265; DOI: 10.3221/IGF-ESIS.46.23 260 stress in the hole edge (Fig. 14a). At the time that, the entrance face and the mid-thickness hole location present the same trend as in the case of  = 3.383%. Fig. 14b shows no change in the distribution of radial residual stresses along the thickness of the expended hole. Figure 13 : Residual stress distribution vs. the distance from the hole edge to the width border for the case of taper  =3.883 %: (a) circumferential stresses and (b) radial stresses. Figure 14 : Residual stress distribution vs. the distance from the hole edge to the width border for the case of taper  =2.875 %: (a) circumferential stresses and (b) radial stresses. Figure 15 : Residual stress distribution vs. the distance from the hole edge to the width border for the case of taper  =2.3 %: (a) circumferential stresses and (b) radial stresses. Figs. 15a and 15b illustrate the distribution of circumferential and radial stresses, respectively for the case of 2.3 % taper. One can note similar tendency as resulted in the case of taper=2.875%. Nevertheless, a slight decrease of compressive circumferential stresses is noted surrounding the exit side of plate (Fig. 15a), indicating that an optimal value for this side is obtained by a taper = 3.833% (Fig. 13a). Furthermore, no change is noted for the radial residual stress through all the hole edge thickness and along the distance from it. a) b) a) b) a) b)