## 3 Results and Discussion
### Fragmentation Resistance Test Results  
Fragmentation resistance tests were carried out for the following groups of ballistic inserts:  
* soft ballistic inserts containing 42 layers of Twaron(r)CT612;
* silicone elastomers used in conjunction with soft ballistic insert containing 42 layers of Twaron(r)CT612;
* HSC composites containing Al\({}_{2}\)O\({}_{3}\) ceramics with a thickness of (3.0 \(\pm\) 0.2) mm used in conjunction with soft ballistic insert containing 42 layers of Twaron(r)CT612;
* HSC composites containing Al\({}_{2}\)O\({}_{3}\) ceramics with a thickness of (3.5 \(\pm\) 0.2) mm used in conjunction with soft ballistic insert containing 42 layers of Twaron(r)CT612;
* HSC composites containing Al\({}_{2}\)O\({}_{3}\) ceramics with a thickness of (3.5 \(\pm\) 0.2) mm, without reinforcing layers in the form of Poron(r)XRDMA and Twaron(r)CT612 sheets, used in conjunction with soft ballistic insert containing 42 layers of Twaron(r)CT612. The test results are presented in Table 5 and Figure 4.  
For the soft ballistic insert, the value of the V50 ballistic protection limit was obtained equal to (619 \(\pm\) 15) m/s. The use of a hybrid silicon-ceramic composite containing ceramic elements with a thickness of (3.0 \(\pm\) 0.2) mm resulted in more than 2-fold increase of resistance to FSP.22 fragment. When comparing composites containing ceramic elements of different thicknesses, it can be determined that increasing the thickness of the ceramic element by about (0.5 \(\pm\) 0.2) mm causes an increase in the \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & & & \multicolumn{2}{c}{V50 [m/s]} \\ \cline{3-6}
**No.** & **Sample** & **Silicone Used in** & \multicolumn{2}{c}{Hybrid Silicone-Ceramic Composites (HSC) Composite Used in} \\  & **Composition** & **Silicone Used in** & \multicolumn{2}{c}{Conjunction with Soft Ballistic Armor, Consisting of:} \\  & **Composition with** & **An\({}_{2}\)O\({}_{3}\) ceramics** & **Al\({}_{2}\)O\({}_{3}\) ceramics** & **Al\({}_{2}\)O\({}_{3}\) ceramics** & **Al\({}_{2}\)O\({}_{3}\) ceramics** & **Al\({}_{2}\)O\({}_{3}\) ceramics** & **Assum 3.0 mm** \\  & & **Soft Ballistic Armor** & **3.0 mm Thickness** & 3.5 mm Thickness and & Thickness without \\  & & **Reinforcing Layer** & **Reinforcing Layer** & **Reinforcing Layer** \\ \hline
1. & MM 922 & 7126 \(\pm\) 20.0 & 1288.8 \(\pm\) 20.1 & 1526.8 \(\pm\) 21.9 & 1530.7 \(\pm\) 24.3 \\
2. & MM 228 & 709.9 \(\pm\) 20.2 & 1324.0 \(\pm\) 24.4 & 1538.9 \(\pm\) 23.2 & 1554.0 \(\pm\) 23.8 \\
3. & Za 22 Mould & 718.4 \(\pm\) 23.2 & 1258.6 \(\pm\) 20.6 & 1543.6 \(\pm\) 21.8 & 1546.3 \(\pm\) 19.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Fragmentation resistance test results. value of the V50 ballistic protection limit in the range of 14-18%. Changes in ballistic resistance of polyethylene composites containing ceramic elements based on SiC and Al\({}_{2}\)O\({}_{3}\) ceramics, depending on the thickness of the ceramic elements used, were discussed in detail in the study of [PERSON] et al. [53]. On the basis of the results contained in this paper, it was indicated that the main parameters influencing the changes in ballistic protection values along with the change in thickness of the ceramic element are acoustic impedance and fracture toughness of ceramic elements. The acoustic impedance should be as close as possible to the acoustic impedance of the base material in the ballistic armor, and the fracture toughness (K\({}_{1c}\)) should be as high as possible. The combination of these two properties gives the best ballistic armor protection when tested with 7.62 \(\times\) 39 mm MSC and 5.56 \(\times\) 45 mm SS 109 ammunition. In the case of tests carried out herein for silicone ceramic composites, the applied ceramics with thicknesses (3.0 \(\pm\) 0.2) mm and (3.5 \(\pm\) 0.2) mm show no differences in the obtained values of density, resistance to brittle fracturing and acoustic impedance.