Research on the Nonlinear Response of the Rotor System with Bolted Joint with Spigot

The bolted joint with spigot is the most common form of joint in the aero-engine rotor system. There will be slip damage at the spigot interface under the complex load, which will influence the dynamic characteristic of the rotor system. However, there are few researches on the spigot interface, so the mechanical characteristic of the non-continuous rotor system cannot be described accurately enough. In this paper, a new mechanical model of bolted joint with spigot has been proposed, which can accurately describe the force-displacement characteristic of the bolted joint with spigot. In addition, the dynamic characteristic of the non-continuous rotor system with the bolted joint with spigot has been calculated, which has been used to analyze the influence of the nonlinear characteristic on the rotor whirl. The results show that the slip process of the spigot interface can been divided into three stages: sticking, microslip and macroslip, with obvious nonlinear characteristic of stiffness, and there may be bifurcation phenomenon in the dynamic response of the non-continuous rotor system. In addition, the influence of the slip damage will vary according to the structure parameters and the excitation, which is necessary to be considered in the robust design of aero-engine rotor system.