Abstract：Abstract: The dynamical equations were established to study a horizontal cracked rotor with rigid supports without weight-dominant control. By applying the neutral axis theory and considering the influence of the open area of crack to the neutral axis position, the open-close regularity of the crack was presented. Based on the moment of inertia and product of inertia, the shaft stiffness coefficient with an open-close crack was investigated. Also, the dynamical characteristics of the system under different crack depth and rotating speeds were studied. The result indicates that the existence of the crack has a major influence to the stiffness in the normal and the tangential directions, while the coupling stiffness is always close to zero. As the depth of crack increases, the switching process of the crack becomes more obvious, and the frequency spectrogram of the response appears more complex with obvious high-order harmonic components. When the rotating speed is set to be fractional to the first-order of the critical speed, the natural frequency of the system will be inspired and the subharmonic resonance can arise.
2012, Vol. 31 
