Research of the crack propagation control in a nonlinear rotor

Due to the continuing action of alternating loads, the micro defects of rotor´s materials and the micro traumas in the mechanic processing will easily cause the crack propagation and even the catastrophic accidents. The vibration characteristics of the rotor system, the crack breathing states and the crack breathing periods are investigated with different parameters of the synchronous state through the numerical simulation, which are all based on the dynamic model of the nonlinear cracked rotor and the describing function of the breathing crack. The crack breathing states are also studied under the asynchronous state. The paper proposes a novel method of the delaying crack propagation using an Electro-Magnetic Actuator (EMA) in order to realize the vibration control and the delaying crack propagation. By comparing influences of the crack breathing state caused by changes of different parameters (rotational speed, crack angle, crack depth and nonlinear parameters, etc.), the paper summarizes the mutation regulations of the crack breathing state in the synchronous and verifies the feasibility of delaying the crack propagation mechanism. The result of the research shows that the EMA can control the vibration of the nonlinear cracked rotor and delay the crack propagation in the running process of the nonlinear cracked rotor.