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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where m t is the mass of the ceramic tile, m b is the bullet mass, v 0 and v r are the initial and residual velocities of the bullet, respectively.

3. Results

Thirteen simulations are performed to explore the e ff ect of surface profiling, and SKEA is used to compare their ballistic performance. We first consider the case when the projectile hits the gap between the four spheres (point A in Figure 4.b). Various sphere radius values ranging from 0 (flat) to 7 mm are examined. Figure 5 shows that if the projectile hits the flat ceramic tile, the SEA value is 11289 J / kg , and this value is marked with a dashed blue line in Figure 5. Among these thirteen surface profiled tiles, the surface profiling increases the ballistic performance when the sphere radius is between 2 mm and 6 mm . The best result is achieved when the sphere radius is 4.5 mm , and in this case, the SKEA value is obtained as 17627 J / kg (56% larger than that of the flat plate).

Fig. 5. E ff ect of surface profiling.

Figure 6 shows the crack formation on a flat plate and on the 4.5 mm radius sphere surface profiled plate. In flat plate, there are more cracks than the surface profiled plate. These results are also coherent with the energy absorption mechanism of ceramic material. Ceramic materials absorb the projectile kinetic energy by fracturing Medvedovski (2010).

Fig. 6. Crack formation on a) flat plate, b) surface profiled plate.