Analysis of vibrations of an innovative civil tiltrotor

This paper presents the assessment of vibratory levels of the tiltrotor ERICA. It is the result of a joint activity of University Roma Tre rotorcraft group and AgustaWestland, within the European Integrated Project NICETRIP. The loads transmitted by the wing to the fuselage are evaluated by a wing-pylon-proprotor aeroelastic model which takes into account the aerodynamic interaction effects dominated by the impact between proprotor wake and wing, as well as the mutual mechanical influence between elastic wing and proprotor blades. The aerodynamic analysis is based upon a boundary integral formulation suited for configurations where strong body-vortex interactions occur, while wing and blades structural dynamics is described through nonlinear beam-like models. A detailed FE model of the fuselage is used to define the transfer functions relating cabin vibrations to the vibratory loads transmitted by the wing. The numerical investigation will consider airplane- and helicopter-mode flight configurations, also examining some of the aeroelastic phenomena most affecting cabin vibrations.