During the first project period, the innovative multipurpose test rig for testing a full-scale new design VTOL aircraft fin, as well as parts of the fin structure like the spar-to-skin joints was designed and manufactured. At the same time, a loading system was developed for loading V-shaped tail surfaces for non-standard flight cases of the VTOL-type aircraft. The developed test rig included a load application mechanism able to apply loads representative of VTOL aircraft tail structures. Moreover, the test rig was designed in a way that a variable stiffness of the fuselage to the fin joint can be achieved. After the first period the structural tests on a new design VTOL aircraft, up to the limit and ultimate loads for several representative load cases were conducted. A huge number of conventional measuring sensors strain gages (SGs), Linear Variable Differential Transformers (LVDTs)), and optical contactless strain measurement systems were installed and applied for data collection. Simultaneously numerical models were developed to perform structural analysis of the fin utilizing the Finite Element Method (FEM). Based on the test data developed numerical models were validated by correlating displacement and strain measurements acquired during the structural tests with the respective numerical results. Additionally, advanced numerical models for the simulation of debonding propagation in composite structural joints were developed. The models were supported by mechanical tests to obtain the material properties required by advanced numerical models for the debonding prediction. Finally, a sub-scale structural test (e.g. on a spar-to-skin joint) was designed and performed. These tests were used for the validation of the debonding numerical models at the sub-component level.
Project results are documented in several deliverables, the project leaflet, and the newsletter. 12 papers were presented at various international conferences (6th International Conference of Engineering Against Failure (ICEAF VI), European Conference on Fracture (ECF 23), EASN International Conference on Innovation in Aviation and Space for Opening New Horizons, International Conference on Strength of Materials, and 7th International Conference of Engineering Against Failure (ICEAF VII)). 4 open access papers were published in scientific journals. The project results were exploited through the two functional samples which document unique solutions of the Attachment of the Fin/aft fuselage segment, and RH dummy system that allows the replacement of one tail surface (FIN) and the introduction of a load into the fuselage so that multiple load cases can be represented without significantly changing the test configurations. This solution achieves significant time and cost savings compared to the situation where a full-scale test with both tail surfaces would be applied. The results of the TAILTEST project will be applied during the development and certification of the new Leonardo Next Generation Civil Tiltrotor (NextGentCTR) aircraft which is the main exploitation activity.
