# A Numerical Study of Blast Resistance of Carbon Fiber Reinforced Aluminum Alloy Laminates
## 4 Results and Discussion
### Influence of Layers on CARALL Impact Response of Curved Surface  
According to the classification of multi-layer FML structure in the figure, three kinds of layering methods, i.e., N = 2, N = 4, N = 8, and four kinds of curvature, i.e., R = 20, R = 60, R = 90, R = 120, were studied. The contour diagram of maximum deformation time is shown in Figure 18.  
Figure 17: Fiber layer energy distribution.  
Figure 18: Influence of layers on CARALL deformation failure modes of curved surfaces.  
As shown in Figure 18, when the structure curvature radius is small (R30 group), the number of layers has no obvious effect on the failure mode of structure deformation, and the matrix fracture failure near the clamping edge is the main failure mode of the fiber layer. With the increase in the curvature radius (R60 group, R90 group), the number of fiber fractures increases as the number of structural layers increases. The fault distribution area expands from near the center to the whole structure. Meanwhile, delamination failure increases. This is because when the number of layers increases, the number of single-layer fibers decreases, and the fiber is more likely to break. At the same time, because there is no continuity between the multilayer fibers (aluminum plate partition), the location of the fault zone between each fiber layer increases, and the overall fiber dimension fault zone increases. When the structure curvature radius is large (R = 120 group), with the increase in the number of layers, the number of fiber fractures increases, and the matrix fracture failure increases; furthermore, there are many axial matrix fractures, and the number of layers and the volume of layers increases. As shown in Figure 19, the maximum deformation of the structure does not change significantly with the increase in the number of fiber layers, and the radius of curvature of the structure is still the main factor affecting the maximum deformation.  
The influence of the number of layers on structural energy absorption is shown in Figure 20. \"All\" represents the total energy absorption amount of the specimen, \"Al\" represents the energy absorption amount of the aluminum alloy laminates, and \"fiber\" represents the energy absorption amount of the fiber laminates. Under the curvature of a single structure, the total amount of structural energy absorption increases with the increase in the number of layers. There is no significant change in the energy absorption of the aluminum plate layer, while the energy absorption of the fiber layer increases more. Since the aluminum plate absorbs the impact energy through plastic deformation, its energy absorption is positively correlated with the maximum deformation at the center, and the  
Figure 19: The influence of the number of layers on the maximum deformation of the central point.  
number of different layers has no great influence on the maximum deformation at the center, so the number of layers has no great influence on the energy absorption of the aluminum plate. Fiber layer energy absorption mainly occurs due to fiber fracture, matrix fracture, and interlayer stratification. When the structural lamination increases, the number of fiber fractures increases, the number of matrix fractures increases, and the number of laminations and the area of lamination increase, so the energy absorption of the fiber layer increases. Therefore, when other structural parameters remain unchanged, increasing the number of failure layers can increase the number of failures and the failure area of fiber layers, thus improving the energy absorption characteristics of the structure.