Since the beginning of AERIALIST project, WP5 had a fundamental role in conducting the initial analysis of the state-of-the-art in the field of acoustic metamaterials, and in the identification of preliminary benchmarks for numerical, manufacturing and experimental techniques. 

This permitted the tuning of the analysis and production tools, also taking advantage of the possibility to gradually increase the complexity of the benchmarks and the availability of data in literature.

The assessment of the advancements of relevant technologies and concepts in the field was continuous throughout the whole duration of the project through a careful monitoring of the outcomes of the worldwide research, in order to maintain an updated knowledge of new emerging concepts and their actual practicability.

Through this analysis, the expected evolution needed of AERIALIST metamaterial concepts towards higher TRL has been outlined in a roadmap document, final aim of the work package. The enhancement of the technology readiness level to values relevant to industry is fundamental to ensure full consideration of the most promising concepts as technologies deserving further investigation and investments. The development path covered aspects related to the manufacturing capacity and the expected impact on the overall aircraft design in a highly multidisciplinary fashion, in terms of weight penalty, performances in the relevant flight conditions, impact of metamaterial devices on production costs and maintenance costs, potential safety issues to be considered and mitigated. The activities in AERIALIST aimed at consolidating the TRL 1-2 of acoustic metamaterials technologies, which are still completely new in aeronautics, and raising to the proof of concept level, i.e TRL3 concepts that shown the highest application potential during the project. The activities involved all the WP and partners, defining a design toolchain that characterize the approach of the project. The AERIALIST design loop has been successfully closed and demonstrated for both metasurfaces and bulk materials, achieving also interesting and promising results.

The main outcome of WP5 has been the roadmap towards TRL of industrial relevance, in which the technology readyness has been analysed separately for metamaterial concepts and devices, introducing hence two levels.

The first level deals with the Manufacturing TRL. The metamaterial concepts analysed tested/stressed the manufacturing capabilities of standard and AM techniques.

The second level, in turn, deals with the development roadmap towards higher TRL of aeronautical device concepts based on the original AERIALIST metamaterial. Aerialist focused on three main devices related to the realization of a VSI, a subwavelength metamaterial enhanced liner and the Surface Shielding Enhancement. The project raise their TRL up to level 3, with experimental proof of concepts achieved with wind tunnel experiments. Future steps, as well as key enabling technologies required to bring the devices to TRL of industrial relevance have been examined.