Issue 41

J.V. Sahadi et alii, Frattura ed Integrità Strutturale, 41 (2017) 106-113; DOI: 10.3221/IGF-ESIS.41.15 112 CX03), with predictions within the bound of half of fatigue life. The inferior performance of the parameter could be attributed to the estimation of shear strain-life coefficients and exponents based on the available normal strain-life curve. Dissimilarly, predictions with the SWT parameter are in better correlation with the experimental data, with less scatter. Most of the fatigue life predictions lie within the two bound lines. The data points closely aligned with the solid black line represent the pure shear (CX05, CX10, CX11), the uniaxial equivalent (CX09) and the minimum von Mises (CX08) cases. The conditions slightly out of the area delimited by the two dashed black line correspond to single actuator and equi-biaxial loading conditions, which presented the largest error. Analogously, the superior performance of this second parameter could be related to its calibration, independent of the shear strain-life curve parameters. Figure 5: Fatigue life predicted with Fatemi-Socie and Smith-Watson-Topper parameters. Exp. № Load case Fatemi-Socie Smith-Watson-Topper Critical Planes    Predicted Life Critical Planes Predicted Life CX01 Single actuator 45º and 135º 7,170 0º and 180º 44,910 CX02 Equi-biaxial 45º and 135º 32,680 0º and 180º 213,570 CX03 Equi-biaxial 45º and 135º 32,680 0º and 180º 213,570 CX04 Single actuator 45º and 135º 7,170 0º and 180º 44,910 CX05 Pure shear 45º and 135º 5,010 0º and 180º 22,790 CX07 Uniaxial Eq. 45º and 135º 9,200 0º and 180º 62,880 CX08 Min von Mises 45º and 135º 16,430 0º and 180º 117,380 CX09 Uniaxial Eq., low ε 45º and 135º 117,910 0º and 180º 842,890 CX10 Pure shear, low σ 45º and 135º 56,460 0º and 180º 302,600 CX11 Pure shear 45º and 135º 5,010 0º and 180º 22,790 Table 3: Fatigue life predictions with Fatemi-Socie and Smith-Watson Topper parameters. Predicted Fatigue Life [cycles]