Experimental Investigations and Numerical Modeling of the Structural Dynamics of the T-Wing Technological Demonstrator

The tiltrotor wing structure is a critical and heavily investigated component in aircraft design due to the need to consider the complex interactions between the wing, pylon, and rotor systems to achieve aeroelastic stability. In this context, vibration testing is a widely used method to assess the modal characteristics of a structure and obtain valuable information to update finite element models. This paper presents the key vibration testing activities conducted as part of the T-WING CleanSky2 project. It is a European-funded project led by CIRA, which aims to develop a composite wing for a flying Technology Demonstrator (TD) of the Next Generation Civil Tilt Rotor (NGCTR). Several experimental tests on lab-scale demonstrators and incomplete full-scale mockups have been carried out to investigate the most effective approaches for characterizing the structural modal properties and to efficiently design the experiments. Due to the unique characteristics of the test articles, both Single-Input Multiple-Output (SIMO) and Multiple-Input Multiple-Output (MIMO) vibration testing techniques have been employed. Preliminary vibration tests on the full-scale mockup involved modal hammer testing and Operational Modal Analysis methods. Additional experimental investigations were also performed to measure and assess the inertia properties of the movable surfaces installed on the tiltrotor wing. The results from these various tests have been used to update and correlate the structural dynamic models, which were subsequently employed for flutter analysis. A range of numerical models, from a simple beam-like reference to a highly detailed representation, have been developed and validated using the experimental modal parameters.