PSI - Issue 41

A.M. Ignatova et al. / Procedia Structural Integrity 41 (2022) 550–556 4 Ignatova A.M., Balakhnin A.N., Bannikov M.V., Kuper K.E., Nikitiuk A.S., Naimark O.B./ Structural Integrity Procedia 00 (2019) 000–000 553

So, each matrix was decomposed into two derivatives: the first one containing the distribution data of structural components with the density corresponding to the grayscale range within 1-255, and the second one containing the data of the regions of the sample’s inner structure, with grayscale values equal to 0 – the “porosity matrix.” The porosity matrices were visualized using the 3D Viewer software module in the 3D space and then processed using the 3D Objects Counter software module. The following characteristics for each element of the matrix werthee obtained: region volume in voxels (a voxel is a 3D analogue of a pixel: an area projected onto the pixel of a tomographic slice), region surface area in voxels, and coordinates of centers of the selected regions. Coordinates of regional centers were used to calculate the distance between the regions. The processing resulted in the data descriptive of the distribution of porosity elements by the value of the dispersion factor (ratio of region surface area to porosity element volume) and distance between the porosity elements. Results and discussion . Fig. 3 shows porosity matrices for the studied sample cutouts.

а

b

c

Fig. 3. Porosity matrices for sample cutouts: (а) unloaded, (b) after loading in the stress raiser zone, (c) after loading along the loading axis.

Fig. 4 contains diagrams describing the distribution of pores by the value of dispersion factor (ratio of region surface area to porosity element volume).

10,00 15,00 20,00 25,00 30,00 35,00 40,00 45,00 50,00

Quantity, %

0,00 5,00

0,9‐1

1‐1,1

1,9‐2

2‐2,1

0,1‐0,2

0,2‐0,3

0,3‐0,4

0,4‐0,5

0,5‐0,6

0,6‐0,7

0,7‐0,8

0,8‐0,9

1,1‐1,2

1,2‐1,3 S/V

1,3‐1,4

1,4‐1,5

1,5‐1,6

1,6‐1,7

1,7‐1,8

1,8‐1,9

2,1‐2,2

2,2‐2,3

2,3‐2,4

2,4‐2,5

2,5‐2,6

образец 1 образец 2 образец 3 Sample Sample Sample

Fig. 4. Distribution of pores by the value of dispersion factor: sample 1 – unloaded, sample 2 – after loading in the stress raiser zone, sample 3 – after loading along the loading axis.