PSI - Issue 41

554 A.M. Ignatova et al. / Procedia Structural Integrity 41 (2022) 550–556 Ignatova A.M., Balakhnin A.N., Bannikov M.V., Kuper K.E., Nikitiuk A.S., Naimark O.B./ Structural Integrity Procedia 00 (2019) 000–000 5 Fig. 5 shows dependencies characterizing the relation of the distance between porosity elements to the dispersion factor value.

Fig. 5. Diagram of distribution of distances between porosity elements depending on the dispersion factor: sample 1 – unloaded, sample 2 – after loading in the stress raiser zone, sample 3 – after loading along the loading axis.

The dispersion factor is primarily the parameter descriptive of the particle’s activity and is inverse to their stability, calculated as the ratio between the surface area and particle volume. However, this parameter is at the same time a morphometric parameter, applicable to the porosity elements. According to the diagram in Fig. 4, the dispersion factor in unloaded samples constitutes 1.77 on average, in samples after loading in the stress raiser zone – 1.74 on average, and in the loaded sample located along the loading axis – 0.74. These results suggest that the pore dispersion factor depends on the deformation conditions. It is known (Ignatova and Vereshchagin, 2017) that the dispersion factor is the higher, the lower is the volume and nominal size of an object; thus, we can say that as the degree of deformation increases, the pore size becomes larger and their dispersion factor decreases. The most notable trend is observed among the patterns illustrated by the diagram in Fig. 5. The distribution of points suggests that the porosity elements can be divided into three groups. The first sample has the following typical division: the first group of porosity elements with a dispersion factor of 1.94-2.21; the second group with a dispersion factor of 1.56-1.89; the third group of porosity elements with a dispersion factor of 0.84-1.51. The second sample has the following typical division: the first group of porosity elements with a dispersion factor of 2.04-2.19; the second group with a dispersion factor of 1.54-1.89; the third group of porosity elements with a dispersion factor of 0.90-1.48. The third sample has the following typical division: the first group of porosity elements with a dispersion factor of 0.79-0.91; the second group with a dispersion factor of 0.43-0.77; the third group of porosity elements with a dispersion factor of 0.10-0.42.