## 3 Results and Discussions
### Ballistic Performances of the 3D Warp Interlock Fabrics
#### 3.1.1 Analysis of Backface Signature Depth and Diameter Values. The BFS maximum depth and the average diameter values of the tested panels are indicated in Figures 10 and 11 respectively. Based on the result, generally, the different warp yarn orientation  
Figure 8: Modeling of the back face signature (BFS) using 3D modeling software and measuring its different values for shot 5. Figure 9: The schematic views of overall ballistic performance analysis. and its ratios inside the structures show a great influence and improvement on the panel's BFS depth and diameters. Involving higher proportions of either binding or stuffer warp yarns inside the 3D warp interlock fabrics brought lower ballistic performance. For example, a sample with a higher stuffer warp yarns proportional ratio (sample 3D-40-4B:8S) faces a complete penetration in all shot points compared to other 3D warp interlock fabrics. Moreover, another target panel made of 3D warp interlock fabric with 100% binding warp yarns (sample 3D-40-8B:0S) were penetrated at the two-shot points, namely shot points 1 and 4. On the contrary, 3D warp interlock fabric samples made with equal or a bit higher interchange ratio of the binding and stuffer warp yarn inside the 3D fabric shows lower back face signature depth values. For instance, as shown in Figure 10, samples 3D-40-8B:4S and 3D-40-8B:8S shows no perforation with less back face indentation depth values of the maximum allowed standard values (44 mm). However, except in target shot point 5, sample 3D-40-8B:4S shows lower backface indentation depth as compared to its counterpart panel made with the same number of 3D warp interlock fabric layers but different warp yarn interchange ratio, sample 3D-40-8B:8S. Numerically, 3D-40-8B:4S shows the minimum and maximum backface indentation value of 20.5 mm and 32 mm in shots 4 and 6 respectively. Sample 3D-40-8B:8S also shows the minimum and maximum backface indentation values of 23 mm and 36 mm in shots 4 and 2 respectively. Sample 3D-40-8B:0S faced penetration at two-shot locations (shot 1 and shot 4) which are located on edges of the right and left deformed bust shapes. Whereas, sample 3D-40-4B:8S were fully penetrated in all the shot points. Besides, the type of fabric constructions (2D and 3D woven) used in the panels was also observed as one of the factors that affect the backface indentation measurements. Samples made of 2D plain weave fabrics having with similar areal density of 3D warp interlock fabrics was penetrated at one shot point (shot 6). Similarly, except for shooting locations 3 and 5, sample 3D-40-8B:4S also shows lower trauma depth values as compared to sample 2D-35. The BFS depth values for the 3D warp interlock fabric structure made with various warp yarns interchange ratios were also revealed higher and nearly similar values among molded shot points (shot 5) compared to the majority of other non-molded shot location (Figure 11). For example, except 3D-40-4/8 where all are penetrated, the maximum BFS depth for  
Figure 10: Maximum BFS depth for different 3D warp interlock variants and 2D plain weave para-aramid fabrics at different shoot locations (*CP—represents the complete penetrated panel at the specified shot point). the 3D-40-8B:0S, 3D-40-8B:4S, 3D-40-8B:8S and 2D-35 were recorded 32, 31, 30.5 and 30 mm respectively at the molded panel area of shot point 5. Unlike other non-molded shot point areas, such back-face signature depth increments in the molded area are due to occurrences of fabric density (thickness) reduction and yarn filament damages during the forming process through stretching of the fabric. Moreover, the influence of warp yarns interchange ratio in 3D warp interlock fabric on average BFS diameter values are also investigated as shown in Figure 11. According to these investigations, sample 3D-40-8B:4S shows a lower BFS diameter compared to all other samples made with 3D warp interlock weave fabric architectures.