Issue 31

R. Citarella et alii, Frattura ed Integrità Strutturale, 31 (2015) 138-147; DOI: 10.3221/IGF-ESIS.31.11 145 Figure 11 : FEM model with highlight of mesh, remote appled tractions and torque. N UMERICAL RESULTS AND DISCUSSION n Fig. 12 it is possible to see the crack propagation, starting from the initial configuration (step 0) and proceeding through the step 11 up to the final step 21: the crack kinking coming from the superimposed torsion is evident. A qualitative comparison between the numerical and experimental (Fig. 7b) crack shape is possible. STEP 0 STEP 11 STEP 21 Figure 12 : Contour plot of Von Mises stresses (MPa) at different stages of crack propagation, with external and internal views of the growing crack. In Fig. 13 it is possible to appreciate the good level of correlation between experimental and numerical (FEM and DBEM [1]) crack growth rates for both the analyzed specimens. The numerical simulation starts from the first traced crack front, so that there is no comparison available in the initial stage of experimental monitored crack growth. I