## 8 Performance vs. Requirements  
A critical overview of the results presented above was organized against the requirements. A summary of this comparison is reported in Table 12.  
Figure 26: Location of the center of gravity (top and lateral view of the cell). Figure 25: Time required for the full activation of the SMA rods of the WhT model vs. power supply. Starting from the additional twist obtained through the SMA actuators, different performance was obtained for the WT and WhT prototypes: 6.27 against 9.16 deg/R. As discussed, this can be attributed to the different constraint conditions. In the case of the WT model, the clamped-pinned condition limits the transmission of twist, hindering the spanwise displacement. However, this constraint configuration imposed by the facility does not describe the real working of the architecture that is supposed to work in clamped-free conditions, for which the requirement is over-satisfied by about 14%. The stress level aligns with the requirements, having achieved a minimum value of 2 and 2.3 for the WT and the WhT models, respectively. The different stress performance between the two prototypes is again due to the constraint conditions that, in the case of the WT model, led to a more pronounced stress concentration. In terms of stress, the SMA material appears compliant with the requirement that, as specified above, in this case, it is not expressed in terms of the safety factor but in terms of stress. Also, in this case, the trend of the stress level between the two models is confirmed with a slightly higher value for the WT prototype (635 against 614 MPa). It is worth noting that both values are slightly lower than the allowed stress of 700 MPa. This small margin meets the need for a high-stress level within the SMA elements to produce enough martensite phase exploitable for the twist recovery. However, possible SMA failure events due to the high stress level are mitigated by the specific layout that incorporates the elements and, thus, limits the potential projection of debris. The temperature requirements were met; that is, starting the activation over 90 \({}^{\circ}\)C and completion at a maximum temperature of 180 \({}^{\circ}\)C, in terms of intrinsic transformation properties of the SMA and in terms of heat transfer. Furthermore, when the thermal analyses of the impact of the power supply on the temperature profile were investigated, we found the minimum power needed for the asymptotic achievement of 180 \({}^{\circ}\)C. A higher power supply can be provided, but, in this case, the use of a logic of control must be considered. The layout considered is compliant with the requirement on the position of the center of gravity with a margin of about 14%, which can be useful in case of the possible installation of sensors not foreseen by the original design. Moreover, if needed, further external masses can be added at the leading edge, at least for the WhT tests, whose focus is mainly on the functionality under centrifugal actions and not on the aerodynamic performance. However, additional external masses must be adequately evaluated for their impact on the stress distribution and level. The deformation level estimated on the plates integrated with fiberoptics also resulted in line with the requirements in terms of maximum range and minimum value to be acquired. The maximum strain estimated was 233 \(\mu\epsilon\), almost one order lower than the prescribed range; this seems a good compromise between the measurement capability, the structural limit of the sensors, and their bonding. Moreover, the minimum variation of strain, 8.8 \(\mu\epsilon\), passing from one configuration to another, results in an acceptably higher than the minimum strain detectable by the sensors, 5 \(\mu\epsilon\), allowing the detection of intermediate configurations. Finally, in line with the requirements, the inclinometers selected for the application offer the possibility of supporting the dedicated logic of shape reconstruction based on strain measurements.