“…On the whole, a validation process can insure the reliability of the design and provide supplementary confidence regarding the optimization [41,50], but on the downside, it is also expected to increase the overall process time and require the input of additional teams like, for example, simulation or prototyping experts [63]. According to this review, there are three possible methods for validating the results of the MDO process, and to this end, the most common approaches are to either use high-fidelity simulations [21,30,33,37,40,41,46,50,58,59,77,109,112]; physical prototypes [34,40,55,63,68,86,97,110,116]; or data from similar aircraft [12,17,21,25,26,79,85,91,92,101]. As far as prototyping is concerned, it can be seen that MDO and additive manufacturing techniques can be easily coupled, and it has been shown that this approach can be a promising combination for both the validation of the results and for establishing a solid foundation towards further subscale tests [34,40,97,116].…”