Dynamics and Reliability Design of Tilt-Rotor Aircraft with Nonlinearity and Stochasticity

This study examines the reliability of a four-degree-of-freedom tilt-rotor model in the presence of random load, taking into account both cubic and freeplay nonlinearities. We discuss the Hopf bifurcation, multistability phenomena, and dynamic responses of the tilt-rotor. To analyze the reliability, we firstly develop a dimensionality reduction method based on diffusion approximation theory and perform the effects of stochasticity on the dynamic behaviors of the tilt-rotor model in detail. Several undesirable phenomena, which ultimately result in the failure of the rotor structure, are induced by random load. Subsequently, the reliability of the tilt-rotor model is defined and analyzed in accordance with the principles of damage accumulation. The impacts of varying parameters on reliability are examined. Additionally, a nonlinear energy sink (NES) is incorporated to mitigate the rotor vibration and damage accumulation in the tilt-rotor model, thereby enhancing the reliability. Reliability regions for the tilt-rotor model are presented to delineate the safety parameter range. The findings demonstrate that the incorporation of the NES markedly enhances the rotor model’s reliability. This research offers novel insights into the safety design of tilt-rotor aircraft.