## 3 Results
### Slamming Tests for Unmodified Panels  
Table 1 shows the tests carried out on the unmodified panels. The variables presented are the slamming pressure in kN/m\({}^{2}\) applied by the equipment on the contact surface, the number of cycles applied and the frequency in RPM of the impacts. The frequency variation depended on the motor-variator, so that the pressure on the cam does not produce loads that affect the system.  
In the 810 kN/m\({}^{2}\) and 830 kN/m\({}^{2}\) panels, the number of cycles of each group in these panels depended on the temperature of the cam which, due to friction, reached 70 \({}^{\circ}\)C. These panels had greater damage, in a low number of cycles of the order of \(2\times 10^{4}\).  
Panel D reached 85% damage in the area of contact with the cam. It was observed that the first micro cracks appeared at \(2\times 10^{2}\) impacts and were already highly visible at \(1\times 10^{2}\) cycles. The first damage observed as slight white shadows were in the areas where the sides of the cam meet. They then lined up toward the center of the contact surface and show the evolution of damage as slamming strokes increase. Figure 9 shows the results of the test.  
Damage spread could be observed in real time at this pressure level and was first expanded by the penultimate laminated \(-45^{\circ}\) layer on the strain gage side. At the end of the test it was found that breaks had already formed in the panel that passed from side to side in the laminate. Normalizing the percentage of damage between the maximum damage area value for each test in panels A-E. It is observed in Figure 10 that the evolution of the damage has a similar behavior for low energy impacts,  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Panel \#** & **Pressure (kN/m\({}^{2}\))** & **Cycles (\(\times 10^{5}\))** & **Frequency (RPM)** \\ \hline A & 260 & 2.10 & 210 \\ B & 400 & 1.50 & 220 \\ C & 630 & 1.81 & 220 \\ D & 810 & 0.21 & 310 \\ E & 830 & 0.21 & 310 \\ F & 420 & 0.27 & 310 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Variables used in unmodified panels for slamming tests.  
Figure 9: Evolution of unmodified panel D damage at \(0.21\times 10^{5}\) impact cycles with P = 810 kN/m\({}^{2}\).  
and similar behavior for high energy impacts. This according to the pressure values presented in Table 1 values used in the slamming tests of unmodified panels.  
The change in flexural stiffness was evaluated with the results of the strain gage using panel F. In Figure 11 are the results of the for a deformation of \(1\times 10^{3}\)\(\mu\)m/m at the slamming pressure point in the \(0.27\times 10^{5}\) test cycles with a pressure of 420 kN/m\({}^{2}\). The data has a representative ascending line, which indicates that as the micro cracks increase, the panel loses rigidity. This is in accordance with the type of damage observed on the panel on the opposite side of the impact. These values were calculated from the deformations obtained with the strain gages.  
These results will be considered for the relationship between low energy slamming impacts and vertical weight drop tests. It is clearly identified in the results that some values presented in the graph correspond to high energy tests, and other tests correspond to low energy tests. Composite material has a defined energy absorption boundary.