Issue34

R. Citarella et alii, Frattura ed Integrità Strutturale, 34 (2015) 514-523; DOI: 10.3221/IGF-ESIS.34.57 516 Figure 3 : DBEM un-cracked model with highlight of mesh, yz symmetry plane, load introduction (tractions and point force) and modelling strategy, based on two distinct zones with normal gap (highlighted in red) at the axle-hub interface. Cracked DBEM model Subsequently to the DBEM stress analysis on the uncracked axle-hub coupling, a semi-elliptical crack has been inserted on the axle in the position shown in Fig. 4. After the crack insertion (that is fully automatic together with the inherent local remeshing), the number of quadratic elements and dofs increases from 2512 and 31650 to 3134 and 48621 respectively. Figure 4 : DBEM cracked model with close up of the re-meshed area surrounding the crack and details of the initial crack geometry (for the initial crack A=B=3.8 mm and C=1.9 mm). DBEM ( AND FEM) RESULTS Uncracked DBEM model or each of the three aforementioned load cases the Von Mises stress scenarios are presented (Figs. 5-7), in order to highlight the impact of each load case on the axle level of stress. The bending load case is responsible for high level of stresses in correspondence of the (red colored) area that will be selected for crack insertion (Fig. 5). Such area is clearly impacted by the press fit condition (Fig. 6) becoming a highly stressed area when the simultaneous application of both load cases is considered (red colored area to the left of hub insertion area in Fig. 7). F