PSI - Issue 83

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

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Errore. L'origine riferimento non è stata trovata. shows the Finite Element simulation results, which comprise three aspects of displacement, Von Mises stress, and strain. Displacement analysis is done to evaluate the deformation behavior of the lattice structure under loading conditions. Excessive displacement might cause micromotion at the bone-implant interface which affects osseointegration and implant stability. Study have shown that 150 micromovement is considered excessive which leads to weak fixation and risk of implant loosening while micromovement up to 28 can promote bone ingrowth [29]. Therefore, an optimal displacement range is essential to achieve balance between structural stability and biomechanical compatibility. The Gyroid lattice shows a lowest displacement of 1.41077 x 10 -2 mm under a 1000N force, which indicates it is the stiffest structure under compressive load compared to Schwarz P, which deforms the most of 2.68845x 10 -2 mm. All three lattices have the maximum micromovement lower than 28 m, which fulfils the condition which promotes bone ingrowth. Stress is evaluated in this study to determine the load-bearing capacity and structural integrity of the lattice structure under loading. Structure often fails due to critical stress regions in the structural design. The design’s safety is verified by confirming that the maximum stress is below the material’s yield strength. Stress evaluation helps in comparing the load distribution of different lattices as lower stress concentration indicates a better load distribution over the lattice. Furthermore, stress analysis is crucial for ensuring biomechanical compatibility as excessive stress can lead to implant failure due to bone resorption or known as stress shielding. The hybrid lattice shows the highest stress of 1126.269MPa while the yield strength for Ti6Al4V is 1100MPa, which means the structure will fail. The stress tends to concentrate at the sharp connecting points of the hybrid lattice. Gyroid has the lowest Von Mises stress of 433.081 MPa, which can spread stress evenly and avoid stress concentrations. Schwarz P has a slightly higher Von Mises stress of 552.741 MPa compared to Gyroid. Both Gyroid and Schwarz P have a lower maximum stress than yield strength of Ti6Al4V, which means it is structurally safe. Strain analysis is done to understand the local deformation behavior of the lattice structure. According to Wolff’s law, bone continuously adapts its internal structure according to the mechanical load applied. Stress shielding will occur when the strain level is too low which increases the risk of microfracture and eventual failure. On the other hand, high strain value will increase risk of local fracture which leads to implant instability. The ideal mechanical strain lies between 100 and 2000 microstrain, but this value varies depending on factors such as the loading frequency, bone type and location, and individual’s age and hormonal condition. Hybrid lattice has the highest strain of 3.69041 x 10 -3 compared to Schwarz P of 2.4998 x 10 -3 and Gyroid of 1.47316 x 10 -3 . This can be explained by the stress distribution characteristics of the lattices where the Gyroid can distribute stress evenly throughout the lattice, resulting in lower localized loads, while stress concentration occurs in the hybrid lattice, which causes more force to be delivered to the bottom surface. The strain of all the lattice are close to the ideal mechanical strain of 2 x 10 -3 . Table 3. Finite Element simulation results Aspects Schwarz P Gyroid Hybrid Displacement (x 10 -2 mm) 2.6885 1.41077 2.56355 Von Mises Stress (MPa) 552.741 433.081 1126.269 Strain (x10 -3 ) 2.4998 1.47316 3.69041 Figure 4 shows the stress distribution diagram for Gyroid, Schwarz P, and hybrid lattice, respectively. Banded color was used to have a better visualization of stress distribution rather than continuous color. Schwarz P and Gyroid have a brighter overall surface color, indicating the stress is well-distributed across the lattice, while the hybrid lattice has a darker blue color covering most of the lattice surface and with certain places colored with bright yellow or red, indicating there is uneven stress concentration in the lattice. Gyroid has the best stress distribution among the lattices, except for some points at the side with slightly higher stress. It can also be seen from Errore. L'origine riferimento non è stata trovata. that the Von Mises stress for the hybrid lattice is the highest. This is due to a weakness in the hybrid lattice, which is stress concentration at the sharp connecting points that behave like a strut-based lattice. These are the critical points where stress concentrates and it is possible to break first while stress is applied.