Abstract: The stiffness uncertainty of bolted joint structure plays an important role in dynamic characteristics of the rotor system. The influences of the uncertainty of the axial stiffness on the vibration behaviors of the bolted joint rotor system are studied. Firstly， the motion equations of the bolted joint rotor system are established based on the finite element method， and then the stochastic dynamic model with uncertainty of axial stiffness of bolted joint structure is obtained by the nonintrusive polynomial expansion method. Finally， the dynamic characteristics is illustrated. The results show that the axial stiffness uncertainty will affect the critical speed and the steady response amplitude of the rotor system. The response amplitude of the disk in the vertical direction decreases as the increasing of axial stiffness uncertainty. The results can provide a theoretical reference for the design of the bolted joint rotor system.

Key words: bolted joint, rotor system, stiffness uncertainty, polynomial expansion, dynamic characteristics