PSI - Issue 76

Daniele Rigon et al. / Procedia Structural Integrity 76 (2026) 35–42

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Fig. 2. (a) The setup used for the comparison of Optical Profilometry (OP) and X-ray Computed Tomography (CT). (b) Post-processed surface for the k-th scan, including noise removal with an S -filter, form elimination with an F -operation, and waviness removal with an L -filter. White frame is the actual region considered to avoid edge e ff ects. (c) Reconstruction of the entire surface, showing the net area of each scan (6.76 mm 2 ) and the reference area A ref where S mea v , max , i is extracted. (d) Schematic illustration of the procedure to extract random selections of S v , j from the 16 scans and determine S est v , max , i dealing with measurement of AM as-built surfaces (Zanini et al. (2019)). Following 3D volume reconstruction and local-adaptive surface determination, internal defects, which frequently occur in PBF-LB / M components (Bonato et al. (2024)) - were measured using VGStudio MAX (Volume Graphics, GmbH). For each defect, the square root of its projected area on a plane perpendicular to the specimen’s axis was computed. This parameter was further analyzed in relation to the minimum distance from the net-shape external surface of the specimen. v , max , i as a function of the sample size composed of the S v , j values, together with the corresponding 95% confidence band. The figures highlight that the estimated value stabilizes around a steady-state value, starting from a number of data greater than approximately 10 with a deviation that decreases as the sample size increases. Figures 3 compare the value of S est v , max , i obtained with 240 samples with the values measured throughout the scanned surface, S mea v , max , i . It is noted that the percentage di ff erence between the estimated and measured values is less than 5%. Figure 3d shows the Gumbel probability plot of a sample of 120 S v , j values, extracted from specimen Ti64-19 (Figure 3c), which were used to estimate S est v , max , i . It can be seen that the data are well represented by the Gumbel distribution, as the straight line reported in the plot demonstrates. 4. Experimental results and discussion Figures 3(a–c) show the results of the estimates of S est