Turning maneuver caused response in an aircraft rotor-ball bearing system

This paper focuses on the nonlinear response caused by aircraft turning flight in a rotor-ball bearing system with internal clearances and Hertzian contact forces. The equations of motion are formulated by using Lagrange equation, where the aircraft turning flight is modeled as a maneuver load. Numerical analyses are carried out to detect the response of the system under maneuver load. The sub-harmonic resonance and irregular motions subjected to the maneuver load are obtained and presented by bifurcation diagrams, amplitude spectrum diagrams, Poincare maps and phase portraits. Two typical patterns that the maneuver load inducing response are found: one is the alternating of period 2 motion and period 1 motion for omega = 1,350 rad/s; the other is the alternating of quasi-periodic motion and period 2 motion for omega = 1,470 rad/s. Moreover, mass eccentricity shows a significant effect on the sub-harmonic resonance of the rotor-ball bearing system under turning flight, which is different from that without considering maneuvering flight condition (Bai and Zhang in Int J Nonlinear Mech 50:1-10, 2013). The results obtained in this paper will contribute an understanding of the nonlinear dynamic behaviors of aircraft rotor systems in maneuvering flight.