PSI - Issue 80

R. Salem et al. / Procedia Structural Integrity 80 (2026) 256–268 Rania Salem / Structural Integrity Procedia 00 (2025) 000 – 000

265

10

Fig. 6 : Comparison of FEA, Voigt and MT homogenized Young’s moduli as function of porosity volume fraction in different condition s

Across all bonding conditions, the predominant trend is a decrease in effective Young's modulus with increasing global porosity. This aligns fundamentally with established micromechanical principles: porosity reduces the load-bearing cross-section. Conversely, ( Fig. 6 a ) reveals a nuanced porosity size effect at the strut level: a slight increase in Young's modulus occurs despite rising overall porosity. This counterintuitive result stems from volume compensation. While total porosity increases, non-bonded region (NBR) volume fraction ( ) also rises, and the two bonding regions volume fractions ( and ) decrease, as shown in Fig. 7 . Here, the NBR compensates for weak bonding regions (HBR/VBR), which exhibit a low modulus (~1500 MPa), and the presence of voids that severely degrade the stiffness.

Fig.7: Porosity-Dependent Evolution of Homogenized Modulus, Bonding Regions (HBR/VBR), and matrix (NBR) volume fraction