PSI - Issue 80

Francesco Manni et al. / Procedia Structural Integrity 80 (2026) 177–186 Francesco Manni/ Structural Integrity Procedia 00 (2019) 000–000

179

3

Fig. 1. Tooth fracture.

3. Discretization and boundary conditions 3.1. Discretization details As shown in Fig. 2 (a), the components under examination consist of a gear train composed of three intermeshing gears. Particular attention has been paid to the gear shown in yellow, which has undergone nitriding. Fig. 2 (b) shows the discretized domain. In particular, during the discretization process of the components, the following approach has been adopted. As shown in Fig. 3, the nitrided region has been discretized using several layers of hexahedral elements with constant thickness to cover the entire section affected by the treatment. Consequently, a locally very fine mesh has been necessary both to ensure adequate accuracy and to allow the application of boundary conditions, as explained in the following section. The remaining volume of the gear has been discretized using tetrahedral elements with element size gradually increasing toward the inner regions. To minimize the computational complexity of the simulation, all non-essential areas of the domain have been removed from the model. Only four teeth of the treated gear have been retained. In fact, through a previous sensitivity analysis, it has been observed that the presence of additional teeth in the model has not led to significant changes in the results. For the gear meshing with the treated one, the same number of teeth have been kept in the meshing zone. Hexahedral elements have been used for the entire teeth, while tetrahedral elements have been used for the rest of the gear. As for the third gear, only the surfaces of the two teeth in contact have been discretized. a b

Fig. 2. (a) CAD model, (b) discretized domain.