PSI - Issue 57

Jacques BERTHELLEMY et al. / Procedia Structural Integrity 57 (2024) 872–903 J. Berthellemy / Structural Integrity Procedia 00 (2023) 000 – 000

895

Fig. 41-a: Nurbs based chancroid model H/R = 0.35 SCF = 1.70

Fig. 41-b: Probability of crack initiation diagram p = 1.17E-6

The simple substitution of a nurbs for the perfect spheroidal shape of the canker is enough to obtain the worst experimental results presented by Kunz et al. and this geometry was adopted for the parametric study. The Effective Notch Stress Method procedure with Code_Aster provides a detail category of 75 MPa instead of 125 MPa for the usual steel surface. Class = 100 / exp ( -0,3333 * ln ( 1/ ( 2E6 * 1.17E-6 ))) ~ 75 MPa To go further, we varied the H/R coefficient from 0 to 0.400 in association with a geometry from the rotation of a nurbs :

Fig. 42-a: Nurbs model with H/R = 0.050

Fig. 42-b: Nurbs model with H/R = 0.350

Fig. 42-c: Nurbs model with H/R = 0.400

The obtained evaluation of the category of detailof the steel surface is as follows in Figure 43. The next lower detail rule of the Eurocode only corresponds to a ration H/R=0,052. When these results were discussed in the committee of Eurocode 3 1-9, it appeared that these chancroid notchs could have an influence on the detail category of certain welded assemblies.