Issue 30

G. Zucca et alii, Frattura ed Integrità Strutturale, 30 (2014) 409-416; DOI: 10.3221/IGF-ESIS.30.49 415 Figure 15 : CAD Geometry (left), mathematical model (right) . Numerical results showed how just the perfect fit was enough to increase the stress value of about 60 MPa. In the real condition of forced coupling (about 25 µm interference) the stress increase would be higher. Stress map Fig. 16 shows how the maximum stress is reached on the outer edge of the case assy. A parametrical simulation was carried out increasing the gap between the actuator case and the cap. Results showed that the stress became null at about 50 µm of gap (Fig. 17). Figure 16 : Stress Map.