1 Dynamic Behavior of Cracked Flexible Rotor Subjected to Constant Driving Torque

The dynamic behavior of a cracked flexible rotor passing through critical speed under the presence of a constant driving torque is analyzed. By incorporating the nonlinear coupling between the bending and torsional degrees of freedom, the model more accurately describes the behavior of the accelerated cracked rotor, especially near the resonance. The breathing types of cracks are considered using simple hinge model for small cracks and cosine function for deep ones. The applied strategy enables to study the cracked rotor dynamic response with and without weight dominance, taking into account also nonsynchronous whirl. The local cross-flexibility for deep cracks is taken into account. The effect of crack on “stalling ” of the rotor is investigated. Under the constant driving torque, the vibration amplitude increases and the stalling angular velocity decreases with the depth of the crack