## 3 Results and Discussion  
### Dynamic Characterization  
The results obtained for each of the processed specimens were then analyzed using the procedure described above, as shown in Tables 2 and 3. We can see some notable differences between the two types of processing. As Figure 9 shows, the processing change caused a 27% decrease in the real part of the \(E^{\prime}{}_{f}\) module, which was practically constant for all frequency values. We also observe in the results how the mean values of equivalent density of the plate decrease markedly due to the effects of porosity; the test processed using VBO had a density 16.2% lower than that processed by A. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \(\rho\left(\text{Kg}/\text{m}^{3}\right)\) & **Mode** & \(\mathbf{f}\left(\text{Hz}\right)\) & \(\mathbf{E}^{{}^{\prime}}\left(\text{Pa}\right)\) & \(\mathbf{E}^{{}^{\prime}}\left(\text{Pa}\right)\) & \(\mathbf{\eta}\) & \(\mathbf{\phi}\left(\text{Rad}\right)\) & \(\mathbf{\delta}\) & \(\mathbf{c}\left(\text{m/s}\right)\) \\ \hline \(1.39\times 10^{3}\) & 2.0 & \(1.17\times 10^{2}\) & \(2.73\times 10^{10}\) & \(6.12\times 10^{7}\) & \(2.24\times 10^{-3}\) & \(2.24\times 10^{-3}\) & \(7.05\times 10^{-3}\) & \(4.44\times 10^{3}\) \\  & 3.0 & \(3.52\times 10^{2}\) & \(3.19\times 10^{10}\) & \(7.85\times 10^{7}\) & \(2.46\times 10^{-3}\) & \(2.46\times 10^{-3}\) & \(7.74\times 10^{-3}\) & \(4.80\times 10^{3}\) \\  & 4.0 & \(7.09\times 10^{2}\) & \(3.37\times 10^{10}\) & \(9.18\times 10^{7}\) & \(2.73\times 10^{-3}\) & \(2.73\times 10^{-3}\) & \(8.57\times 10^{-3}\) & \(4.93\times 10^{3}\) \\  & 5.0 & \(1.17\times 10^{3}\) & \(3.36\times 10^{10}\) & \(1.02\times 10^{8}\) & \(3.04\times 10^{-3}\) & \(3.04\times 10^{-3}\) & \(9.55\times 10^{-3}\) & \(4.92\times 10^{3}\) \\  & 6.0 & \(1.69\times 10^{2}\) & \(3.12\times 10^{10}\) & \(1.28\times 10^{8}\) & \(4.10\times 10^{-3}\) & \(4.10\times 10^{-3}\) & \(1.29\times 10^{-2}\) & \(4.74\times 10^{3}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Average values obtained for CFRE prepreg plates processed by autoclave. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \(\rho\left(\text{Kg}/\text{m}^{3}\right)\) & **Mode** & \(\mathbf{f}\left(\text{Hz}\right)\) & \(\mathbf{E}^{{}^{\prime}}\left(\text{Pa}\right)\) & \(\mathbf{E}^{{}^{\prime}}\left(\text{Pa}\right)\) & \(\mathbf{\eta}\) & \(\mathbf{\phi}\left(\text{Rad}\right)\) & \(\mathbf{\delta}\) & \(\mathbf{c}\left(\text{m/s}\right)\) \\ \hline \(1.16\times 10^{3}\) & 2.0 & \(1.15\times 10^{2}\) & \(2.00\times 10^{10}\) & \(5.18\times 10^{7}\) & \(2.59\times 10^{-3}\) & \(2.59\times 10^{-3}\) & \(8.14\times 10^{-3}\) & \(4.15\times 10^{3}\) \\  & 3.0 & \(3.38\times 10^{2}\) & \(2.25\times 10^{10}\) & \(5.60\times 10^{7}\) & \(2.49\times 10^{-3}\) & \(2.49\times 10^{-3}\) & \(7.81\times 10^{-3}\) & \(4.40\times 10^{3}\) \\  & 4.0 & \(6.78\times 10^{2}\) & \(2.37\times 10^{10}\) & \(3.86\times 10^{8}\) & \(1.63\times 10^{-2}\) & \(1.63\times 10^{-2}\) & \(5.12\times 10^{-2}\) & \(4.51\times 10^{3}\) \\  & 5.0 & \(1.11\times 10^{3}\) & \(2.31\times 10^{10}\) & \(3.93\times 10^{8}\) & \(6.60\times 10^{-2}\) & \(6.59\times 10^{-2}\) & \(2.07\times 10^{-1}\) & \(4.46\times 10^{3}\) \\  & 6.0 & \(1716.18\) & \(2.48\times 10^{10}\) & \(3.91\times 10^{8}\) & \(1.58\times 10^{-2}\) & \(1.58\times 10^{-2}\) & \(4.95\times 10^{-2}\) & \(4.62\times 10^{3}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Average values obtained for CFRE prepreg plates processed by vacuum bag-only. Although both values decrease markedly, we see how the mean frequency values were less than each for both processes, with variations of between 2%-6%. This can be explained by the resulting sound speed of composite \(c\) defined by Equation (6) and represented in Figure 10. It is defined as the square root of the ratio between the stiffness and the density of the medium.