## 2 Materials and Methods
### Experimental Setup and Inspection Methods
The wave front generated by combination of element array pulses at slightly different times allows pulses to direct and distribute the sonic beam and achieve a sharp focus of perfectly distributed beam characteristics [18]. UT phased array (PA) control is conducted using a portable modular unit Olympus OmniScan MXU(Olympus Corporation, Shinjuku, Tokyo, Japan) instrument with an innovative technological 64 elements phased array 2.25L64-A2 probe of thickness 25 mm with 2.25 MHz, a SA2-0L plexiglas longitudinal wedge, with glycerin coupling gel and the Olympus mini-wheel absolute encoder with a resolution of 12 steps/mm for C-scan control mode (as shown in Figure 4a). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**CFRP** & **Side** & **N\({}^{\circ}\) Test** & \multicolumn{2}{c}{**Frame Rate** (Hz)**} & \multicolumn{2}{c}{**Heating**} & \multicolumn{2}{c}{**Acquisition**} & \multicolumn{1}{c}{**Total**} \\  & & & & **(Hz)** & **Time (s)** & **Time (s)** & **Frames** \\ \hline \multirow{4}{*}{Plate I} & \multirow{4}{*}{A} & 1 & 5 & 20 & 100 & 500 \\  & & 2 & 5 & 30 & 100 & 500 \\  & & 3 & 5 & 40 & 100 & 500 \\ \cline{2-6}  & & 4 & 5 & 12 & 200 & 1000 \\  & & 5 & 5 & 15 & 200 & 1000 \\  & & 6 & 5 & 20 & 250 & 1250 \\ \hline \multirow{2}{*}{Plate II} & \multirow{4}{*}{A, B} & 7,8 & 5 & 12 & 200 & 1000 \\  & & 9,10 & 5 & 15 & 200 & 1000 \\ \cline{1-1}  & & 11,12 & 5 & 20 & 250 & 1250 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Scheduling tests for the investigations with different heat pulses. Figure 3: (a) Top view of the thermographic setup for CFRP plates’ acquisition and (b) experimental setup. The authors used the UT C-scan technique to provide a two-dimensional representation of defects in a specific parallel plane below inspected surface and scans of ultrasonic data are synchronized with the unidirectional movement of the probe itself, along the main scan line and this is possible by rigidly coupling an encoder to the ultrasonic probe, moving along a sliding guide. In previous works, appropriate UT tools are designed to allow stable coupling to GFRP components [23] with ultrasonic inspections. In our case, ultrasonic probe must be maintained in a steady orientation and contact conditions relative to inspected component [23] and for this goal, a special bracket is conceived with specific geometric dimensions for Plexiglas wedge (as seen in Figure 4a), constructed in thermoplastic polymeric material PLA with Ultimaker2 3D printer. Figure 4b show experimental setup employed on CFRP component in direct contact with aid of coupling gel, since water stream method would give similar results. Thermal pulsed acquisitions of multi-stringer part are successively performed and focused on central impacted damage area to verify defect data correlation with UT controls. Aeronautical component surface is positioned at a higher distance of 0.72 m from the four halogen lamps than CFRP plates, due to necessary of inspection on a larger delamination zone around the impact simulated cut with a fixed focal point of the camera. Figure 5 shows the thermographic setup that is used for all tests described in the case of computed inspection. Employing this set-up, pulsed thermography is executed on CFRP component, in the central zone; five total tests are conducted, by selecting different heating times (Table 5). Figure 4: (a) CATIA assembly view of new PLA bracket tool and (b) experimental setup for ultrasonic C-scan controls around simulated impact zone of aeronautical component. Figure 5: (a) Lateral view of the thermographic setup for multi-stringer component’s acquisition and (b) experimental setup. All tests are performed in controlled ambient temperature between 21-25 \({}^{\circ}\)C for thermal analysis on CFRP elements, monitored by humidity/temperature data logger PCE-HT110, without input in the camera software.