PSI - Issue 28

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Stepan Major et al. / Procedia Structural Integrity 28 (2020) 561–576 Author name / Structural Integrity Procedia 00 (2019) 000–000

Fig. 8. Box graphs showing spatial orientation of surface elements: at the microscopic level, i.e. square side a 05 = 5 μm: (a) simple bending, (b) simple torsion; at macroscopic level, i.e. square side a 99 = 99 μm: (c) simple bending, (d) simple torsion.

For the following samples characterized by loading ratio L R = 0.23, L R = 0.5, L R = 0.73, we will implement only square network a 99. This is due not only to the small extent of this work, but above all, we have shown, that it is unnecessary. This fact was proved with the help of a pair of the previous two pictures (Fig. 7 and Fig. 8). The results for surfaces generated by bending-torsion are shown in Fig. 9. Also, these graphs clearly confirmed the growing trend of the deviation angle α . This result corresponds to previous studies, which, however, used classical roughness criteria for fracture surface description, Slámečka and Pokluda (2005). The relationship between the deviation angle α and loading condition (i.e. loading ratio L R ) is more obvious in the case of a coarser lattice (square network with longer sides of elementary squares). This fact is advantageous for us, because we do not need to process such a large amount data (equidistant points coordinates) in afford to realize a complex description of the surface.