## 3 Results  
During the initial development phase, numerical trials were performed for small-scale coupons with geometries identical to those of the experimental trials. The low-curvature skins and C-shape specimens were analyzed extensively to understand the model and the effects of its constraints on the distortion results. We constantly used the experimental coupons' and test specimens' data and measurements as benchmark and calibration references. The C-shape specimens were significant in the overall frame of ELADINE, as their experimental and numerical results contained valuable data for the tooling geometrical compensation. This first phase of the numerical model development was also the most intensive of the analyzed specimens. The most straightforward numerical and experimental trials showed distortion behaviors that were remarkably similar in their patterns, as shown in Figure 22. The magnitude of displacement topped a value of 0.10 mm for the measured coupons. At the same time, the spring-in displacement values of the simulated coupon were much higher, topping a 2.79 mm value before the model calibration step. By analyzing the strain map variation and comparing the results with the contour plots of the Z-coordinate variation obtained from the 3D CMM measurement (see Figure 23), a clear strain evolution was observed as the time after demolding increased. On the surface below the strain, higher strain values were concentrated more evenly around the four edges of the coupon. In contrast, on the surface above, the strain was mainly focused on one side of the coupon. The strain stabilized after one week, as the measurements indicate in Figure 24. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Manufacturer** & **Material Description** & **Oven Cure Cycle** \\ \hline \multirow{6}{*}{Toray} & Prepreg P707 AG-15, & 1. Dwell at 40 \({}^{\circ}\)C \\  & unidirectional tape T700 12K & 2. Heat to 80 \({}^{\circ}\)C at 1 \({}^{\circ}\)C/minute \\  & fiber and 2510 resin system. & 3. Dwell 5 Hr at 80 \({}^{\circ}\)C \\  & The FAW is 150 gsm (grams & 4. Heat to 132 \({}^{\circ}\)C at 1 \({}^{\circ}\)C/minute \\  & per square meter) & 5. Dwell 2 Hr at 132 \({}^{\circ}\)C \\  & Dry fiber Hi tape & 1. Heat tool to 120 \({}^{\circ}\)C, resin to 80 \({}^{\circ}\)C \\  & unidirectional type AS7 areal & 2. Infusion process at 120 \({}^{\circ}\)C/80 \({}^{\circ}\)C \\  & weight 126 gsm & 3. Heat to 185 \({}^{\circ}\)C at 2 \({}^{\circ}\)C/minute \\  & RTM 6-2 resin & 4. Dwell 2 Hr at 185 \({}^{\circ}\)C \\  & RTM 6-2 resin & 5. Cool to RT (min. temperature 50 \({}^{\circ}\)C) \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Material systems used for coupon manufacturing and modeling. Figure 22: **(a)** Computed spring-in plot of 80-ply skin coupon (Skin3). **(b)** CMM measurement of an 80-ply skin coupon (Skin3) over a 7-day period. Sensors monitored both the manufacturing process and the stabilization intervals of the quasi-flat laminates. The monitoring results are illustrated in the plots in Figure 25 for process monitoring and Figure 26 for the post-manufacturing period. Figures 27 and 28 show preliminary numerical simulation results of some of the calibration steps taken to understand how the numerical model works compared to the experimental data. A volume fiber fraction gradient was implemented for three plies starting from the bottom face. A variable friction coefficient vs. cure degree between the tool and the part was defined. This parameter was kept for several simulation trials to understand the degree of magnitude of the simulation results. The variable friction coefficient is defined as shown in Figure 29.  
Figure 23: Three-dimensional CMM results for 80-ply (Skin3) coupon taken after 2, 3, 6, and 7 days of demolding in 3D format. Figure 24: Skin3 coupon strain plots of the two different surfaces (below—surface contact between coupon and mold; above—surface contact of coupon with bag) on days 1 (**left**), 9 (**center**), and 13 (**right**) after demolding.