PSI - Issue 83

Wong Kam Chee et al. / Procedia Structural Integrity 83 (2026) 14–27

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Table 4. Stress at the lattice surface comparison Schwarz P (MPa)

Avg Diff (%)

Hybrid (MPa) 9.53906 x 10 2 6.15717 x 10 2 1.53124 x 10 1 5.67197 x 10 1 1.34617 x 10 1 1.45201 x 10 1

Avg Diff (%)

P1 P2 P3 P4 P5 P6

1.03086 x 10 2 6.65382 x 10 1 1.79811 x 10 2 1.92449 x 10 2 1.27500 x 10 2 6.12775 x 10 1

16.41 58.67 38.49 44.98 4.59 66.10

109.66 75.49 179.14 132.27 181.54 180.16

Max Diff Average

1.311715 x 10 2 (103.40%)

9.404443 x 10 2 (194.43%)

121.7770

278.2728

3.2 Modification of Hybrid Lattice According to Von Mises yield criteria, yielding occurs when the von Mises stress reaches or exceeds the material’s yield strength. The maximum Von Mises stress for hybrid lattice is 1126.269MPa while the yield strength for Ti6Al4V is 1100MPa, which means the structure will fail. To improve the hybrid lattice, a simple modification can be made to the original hybrid lattice (H1). The lattice is created in nTopology by subtracting a thinner lattice from a thicker one to obtain the lattice with the desired thickness. By offsetting the mathematical equation by 0.1 for both the thicker and thinner lattices, a new hybrid lattice (H2) with the same thickness is created. This will eliminate the stress-concentrating sharp points and make the lattice surface smoother. This results in better load transfer sufficiency, and it can be shown in Figure 6. H2 has an overall brighter color of orange and yellow rather than the H1 with most of the area colored dark blue. This has shown that stress concentration in the sharp points has been successfully eliminated by transferring to the surrounding area rather than accumulating.

Figure 6. Hybrid lattice before and after modification