Nonlinear response and bifurcation analysis of a Duffing type rotor model under sine maneuver load

• Maneuver load may increase the formant frequency as well as the primary resonance frequencies.
• The maneuver load response curve may show a softening characteristic.
• Four different types of response characteristics of the system during the maneuvering flight are demonstrated.
• Maneuver load makes an obvious effect on the hysteresis characteristics the rotor system.
• Maneuver load may change the bifurcation mode of the system due to some parameter combinations.

This paper focuses on the nonlinear dynamic and bifurcation characteristics of an aircraft rotor system affected by the maneuvering flight of the aircraft. The equations of motion of the system are formulated with the consideration of the nonlinear supports of Duffing type and the sine maneuver load of a proposed maneuvering flight model. By utilizing the multiple scales method to solve the motion equations analytically, the bifurcation equations are obtained. Accordingly, the response and the bifurcation characteristics of the system are analyzed respectively. Basically, the increase of the maneuver load may increase the formant frequency as well as the primary resonance frequencies. Through numerical simulations, four different types of response characteristics of the system during the maneuvering flight are found, which are compared with the theoretical results, and it shows good qualitative agreements between them. Furthermore, the maneuver load can make an apparent effect on the bifurcation. The results in this paper will provide a better understanding for the effect of aircraft maneuvering flight on the dynamics and bifurcations of the rotor system.