PSI - Issue 72

Toeri Fathuddin Yusuf et al. / Procedia Structural Integrity 72 (2025) 436–444

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Fig. 3. Mesh result for mesh size at impact zone 0.0001 mm and at non-impact zone 0.001 mm.

4. Result and Discussion 4.1. Mesh Convergence

FEM analysis was performed using ten mesh size variations for the impact zone of the target plate, namely 0.0005, 0.00075, 0.001, 0.0015, 0.002, 0.0025, 0.003, 0.0035, 0.004, and 0.0045 mm. This mesh size variation aims to determine the mesh size that can predict the residual velocity results from numerical simulations that best match the experimental results, as shown in Fig. 3. The graph in Fig. 3 shows the comparison between mesh size on the x-axis and the ratio of residual velocity from numerical simulation ( ) to residual velocity from experimental results ( ) on the y-axis. The four figures show that when the ratio of and is close to 1, the numerical simulation can predict the residual velocity of the projectile with results close to the experiment. This phenomenon shows that the numerical simulation's prediction of the mesh size used will be influential, although, at some point, the effect of mesh size is no longer significant. The same pattern is seen in all the graphs in Fig. 3, where the deviation becomes smaller, and the graph is more stable when the mesh size reaches 0.0025 mm. In addition, the most accurate prediction of residual velocity values occurs for projectiles with an initial velocity of 565 m/s using mesh sizes of 0.001 and 0.0015 mm. Meanwhile, the projectile with an initial velocity of 863 m/s produces the most accurate residual velocity prediction with different mesh size variations. a) b)

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Pnum/Pexp

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

P num /P exp

0.001

0.002

0.003

0.004

0.001

0.002

0.003

0.004

Mesh Size (mm)

Mesh Size (mm)