PSI - Issue 72

Gusti Kid Faiq Syah et al. / Procedia Structural Integrity 72 (2025) 401–408

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(a) (e) Figure 13. Stress Von Mises Contour 1100-H12 Aluminum mesh 1.5 mm: (a) 0 s, (b) 0.2 s, (c) 0.4 s, (d) 0.6 s, and (e) 0.8 s. Figure 14 offers a detailed visual representation of how the plate's projectile residual velocity and energy absorption change when the impact is loaded with various meshes. This informative graphic helps clarify the dynamic interactions between projectile velocity, energy absorption, displacement over time, and the resulting structural response, significantly enhancing our understanding of the complex dynamics that affect structural behavior under various mesh parameters and conditions. The outcomes of ballistic impact simulations, which involved different mesh geometries, demonstrate a notable effect on residual velocity. Observations from meshes ranging from 0.6 mm to 1.5 mm indicate that smaller mesh sizes resulting more accurate results. (b) (c) (d)

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0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 0 1 2 3 4 5 6 7 8 9 10 Energy absorbed (J) Mesh (mm) Energy absorbed

Residual Velocity

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40

Residual Velocity (m/s)

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0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 0

Mesh (mm)

(a) (b) Figure 14. Results of the simulation with mesh variations: (a) residual velocity, and (b) absorbed energy.

Von Mises stress measures the stress level experienced by the aluminum target plate. In ballistic impact simulations, this stress notably increases when it surpasses the material's elastic limit, leading to deformation, as shown in Figure 4. Additionally, numerical simulations indicate that variations in mesh significantly affect residual velocity. The results underscore the intricate relationship between von Mises stress, structural response, and mesh parameters, highlighting the importance of considering material properties and geometry when evaluating structural integrity during ballistic impacts. This study offers valuable insights into how flat aluminum plates behave under stress from ballistic impacts, enhancing our understanding of structural dynamics in these situations. 4. Conclusions Based on extensive numerical studies conducted with LS-DYNA, it can be concluded that the distribution of von Mises stress is significantly affected by the mesh applied to a structure, regardless of the material type. Specifically, the residual velocity values of the projectile show a direct correlation with mesh size, and larger meshes tend to produce lower residual velocities than smaller ones. However, it is essential to note that the inherent strength properties of the materials involved influence this relationship. Consequently, it can be inferred that the mesh size affects stress