PSI - Issue 35

Deniz ÇelikbaŞ et al. / Procedia Structural Integrity 35 (2022) 269 – 278 D. C¸ elikbas¸ / Structural Integrity Procedia 00 (2021) 000–000

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Next, the e ff ect of surface profiling with di ff erent hitting locations is examined. Twenty-five di ff erent simulations are performed, and the results are shown in Figure 7. Various locations in which the projectile may hit are shown in Figure 4.b. The sphere radius values of 3.5, 4, 4.5, 5, and 5.5 mm are considered in this analysis. The flat plate’s SKEA value is marked with the green dashed line in Figure 7. When the sphere radius is 4.5 mm , the least protective result is achieved when the projectile hits point D; however, this result is still 21% better than the flat plate. Except for the 5.5 mm sphere radius surface profiled plate, the best results are achieved when the projectile hits the gap between the four spheres (point A in Figure 4.b). For the 5.5 mm sphere radius surface profiled plate, on the other hand, the best SKEA result is achieved when the projectile hits the gap between the two spheres (point E in Figure 4.b). For radius values of 3.5, 4, 5, and 5.5 mm , the worst SKEA result is obtained when the projectile hits the top of the sphere (point C in Figure 4.b). For the radius value of 4.5 mm , however, the worst SKEA result is obtained when the projectile hits in the middle of the top and the intersection of two spheres (point D in Figure 4.b). As noted earlier, the ballistic performance is better than the flat plate regardless of the hitting point because the worst result is 21% better than the flat plate.

Fig. 7. E ff ect of di ff erent hitting locations.

Table 5 shows the achieved improvements of surface profiling. For each hitting location, the best SKEA value is shown in bold. When the projectile hits point A, the best SKEA results are accomplished with the radius of 4.5 mm . When the projectile hits point B, the spehere radius of 3.5 mm yields the best results. Almost all radius values give the worst results in point C, and the best SKEA result for point C is obtained when the sphere radius is 4 mm . For point D, three radius values leads to the same level of improvement in SKEA. Lastly, for point E, the best results can be achieved if the radius of the sphere is 5.5 mm .

Table 5. SKEA improvements for di ff erent radii. Hitting Locations r = 3.5 ( mm )

r = 4.0 ( mm )

r = 4.5 ( mm )

r = 5.0 ( mm )

r = 5.5 ( mm )

56% 31% 36% 21% 41%

A B C D E

51% 45% 32% 38% 42%

49% 44% 40% 38% 44%

44% 28% 23% 38% 35%

45% 23% 21% 32% 47%

4. Conclusion

In this work, the e ff ect of surface profiling and bullet hitting locations on the ballistic performance of ceramic tiles are examined with numerical models with SPH formulation. To validate the ceramic tile model, we use experimental