Issue 35

J. Kramberger et alii, Frattura ed Integrità Strutturale, 35 (2016) 142-151; DOI: 10.3221/IGF-ESIS.35.17 147 model in the direction of applied load. With increasing cycles, the width of loop increases and the slope decreases. The changes are most predominant for irregular pore structure. Figure 6 : Equivalent plastic strain contours (PEEQ) for global deformation of 0.3% (elasto-plastic response): a) aligned, b) 45° rotated, c) shifted and d) irregular regular models. Figure 7 : Hysteresis loops observed during 3 fatigue cycles for global strain range  = 0.27% . The damage initiation can be quantified by plotting the number of cycles required to damage initialization (Fig. 8). Strain intensification serves as areas for crack initiation. Our modeling shows that that crack initiation begins the fastest at model with irregular pore structures. a) b) c) d)