Orbital Analysis of a Breathing Cracked Rotor During its Passage Through the Subcritical Speeds

In the present paper, an orbital analysis is conducted to study the effect of a transverse breathing crack on the orbits of the rotor during its passage through the subcritical speeds; this study makes it possible to predict the presence of cracks in rotors. The classical version of the finite element method is used to model the rotor. While, the equation of motion is obtained by the application of the Lagrange equation on the kinetic and deformation energies of the different components of the rotor taking into account the variation of the shaft's stiffness due to the crack, The results are obtained using a Matlab code based on Newmark's beta method, this program allows us to plot the orbits of the rotor centre during its passage through the subcritical speeds.