Issue 41

A. S. Cruces et alii, Frattura ed Integrità Strutturale, 41 (2017) 54-61; DOI: 10.3221/IGF-ESIS.41.08 58 Fatemi-Socie damage parameter II It can be observed from the plots in Fig 2 that the maximum value of Fatemi-Socie damage parameter and the maximum value for shear stress range is not at the same time point, which implies that the plane of maximum shear and plane of maximum damage parameter is far apart. Figure 2 : IP 1 – σ, τ and FSDP-II at max peak cycle (A) and min peak cycle (B). FSDP-II was computed for all the test data shown in Tab. 4, and the damage parameter value was presented against the cycles to failure. The plot is shown in Fig 3, and it can be noticed that the FSDP-II models most of the LCF fatigue behavior data but it produces significant scatter in the HCF data range. Figure 3 : Fatigue life correlation for St52-3N steel based on Fatemi II model Suman-Kallmeyer Damage parameter In contrast to Fatemi-Socie damage parameter, the difference in the location of maximum shear stress range plane and the plane where the value of Suman & Kallmeyer damage parameter value is maximum is much smaller. While computing the damage parameter for the proportional load path, computation of maximum shear plane was comparatively easy.