Analytical model of bolted disk- drum joints and its application to dynamic analysis of jointed rotor

Bolted joints are widely used in aero-engines. One of the common applications is to connect the rotor disks and drums. An analytical model for the bending stiffness of the bolted disk-drum joints is developed. The joint stiffness calculated using the analytical model shows sound agreement with the calculation obtained based on finite element analyses. The joint stiffness model is then implemented into the dynamic model of a simple rotor connected through the bolted disk-drum joint. Finally, the whirling characteristics and steady-state response of the jointed rotor are investigated to evaluate the influence of the joint on the rotor dynamics, where the harmonic balance method is employed to calculate the steady-state response to unbalance force. The simulation results show that the joint influence on the whirling characteristics of the rotor system can be neglected; whereas, the presence of the bolted disk-drum joint may lead to a decrease in the rotor critical speeds due to the softening of the joint stiffness. The proposed analytical model for the bolted disk-drum joints can be adopted conveniently for different types of rotor systems connected by bolted disk-drum joints.